Optimisation of the secondary ball mill using an on-line ball and pulp load sensor – The Sensomag

The ball load and pulp load have a significant influence on the ball mill product size and production capacity. To improve the circuit performance at industrial scale these variables must be tweaked to levels where the plant can get grind and capacity benefits. In most grinding circuits the influence of these variables are not quantified because it is difficult to obtain precise measurements of the pulp load for an industrial scale mill and the conventional method of obtaining ball load measurements that involves crash stops is not attractive. A comprehensive investigation was performed on an industrial scale mill to quantify the effects of both ball and pulp load. A wide range of ball and pulp loads were tested and the findings are reported in this paper. The Sensomag, a sensor developed by Magotteaux, was used to obtain ball and pulp load measurements during the experimental work.     

Fracture toughness of coated TiCN–WC–Co cermets with graded composition

Mixed TiCN–WC–Co cermets are developed to improve at the same time toughness and resistance to deformation of materials for cutting tool applications. Moreover, graded materials joining optimum properties according to the functional part of the tool are elaborated. To this end, TiCN–WC–Co cermets are interesting because they develop a WC–Co layer at the surface during the sintering. This tough layer at the surface limits the crack propagation that can lead to the rupture of the tool. Such materials show a good resistance to the deformation in the bulk and a good toughness at the surface, where the cracks are initiated upon machining. Cutting tools are often coated by CVD to improve the wear resistance. This paper proposes a method to measure the toughness K_IC at high temperature by using this CVD coating for initial crack formation. The coating thickness is the precrack length of traditional K_IC measurements. Samples are fractured by three point bend tests. The rupture stress is measured by Weibull statistics. This method is particularly interesting for graded structure materials where the influence of surface layers on toughness must be estimated. The comparison between cermets with and without WC–Co layer shows an improvement of 28% of the toughness when the layer is present. The possible bias of internal stresses on the results is discussed.     

Effect of pH and Temperature on the Viscosity of Texturized and Commercial Whey Protein Dispersions

Apparent viscosity (η_a) of texturized whey protein concentrate (tWPC80) produced using supercritical fluid extrusion process was compared with commercial WPC-80 as a function of pH (3.0 to 9.0) and heating temperatures (25 to 80°C). The tWPC80 exhibited shear thinning behavior and yielded 2 to 10-folds higher η_a than commercial WPC-80 at all pH and temperatures studied. The η_a of tWPC80 decreased as pH was increased from 3.0 to 9.0. The η_a of both samples was always higher at pH 3.0 than at pH 7.0 due to acid-induced aggregation in the former. The ability of the tWPC80 to perform as a food thickening agent was also compared with other commercial thickeners. The tWPC80 offers as a desirable ingredient for many food formulations currently utilizing starches and polysaccharides as texture modifying agents.     

Study of the mechanical properties of TiCN–WC–CO hardmetals by the interpretation of internal friction spectra

TiCN–WC–Mo–Co mixed carbide hardmetals have an interesting application potential for cutting tool fabrication combining the high toughness of WC–Co with the resistance to plastic deformation of TiCN–Co cermets. Mechanical spectroscopy (MS) is used in order to separate the effects of the constituents on the mechanical properties. Internal friction (IF) spectra are measured in a torsion pendulum on WC–TiCN–Mo–Co samples where TiCN/WC ratio is varied as well as the Co content. Six components of the characteristic IF spectrum of WC–TiCN–Mo–Co have been identified and interpreted. Two peaks are located in the cobalt, two peaks in the TiCN phase and two peaks in the ceramic grain boundaries. Four temperature domains are defined depending on the mechanical behaviour: brittle (I), anelastic (IIa), limited plasticity (IIb) and extended plasticity (III). The anelastic domain is characterized by the bulk deformation of cobalt. In the limited plasticity domain, both cobalt and TiCN are deformed by dislocation movement. The high temperature extended plasticity should be attributed to grain boundary sliding in the ceramic phase (mainly WC) enhanced by cobalt diffusion in the grain boundaries.     

Simulation of polymer flow through a coat-hanger die: A comparison of two numerical approaches

Coat-hanger dies are commonly used for the extrusion of plastic sheets and films. To describe the flow of a molten polymer through a coat-hanger die, a two-dimensional approach is necessary. Moreover, the thermal effects, which play an important role in the flow distribution, have to be taken into account. In this paper, two numerical models for the simulation of coat-hanger dies are described and compared. These models differ mainly in the simplifying assumptions used and in the treatment of the thermal problem. The simulations obtained with the two models were compared with each other and with experimental data. The discrepancies between the two models can be explained by the different theoretical treatments.     

Encoding and selective activation of "metabolic memories" in the rat.

Experiment 1 used Pavlovian conditioning procedures to show that rats formed distinct memorial representations of 2 (peanut oil and sucrose pellets) unconditioned stimuli (USs) that could be activated by 2 different conditioned stimuli (CSs). After training in Experiment 2, rats injected with the lipid antimetabolite Na-2-mercaptoacetate (MA) responded more to the CS for oil than to the CS for sucrose. This pattern was not shown by rats that received isotonic saline or systemic 2-deoxy-d-glucose (a glucose antimetabolite). By contrast, intracerebroventricular infusion of the glucose antimetabolite 5-thioglucose selectively promoted responding to the CS for sucrose (Experiment 4). Thus, lipoprivic and glucoprivic treatments selectively promoted the activation of the memories of fat and carbohydrate USs, respectively. In Experiment 3, the capacity of MA to augment responding to a CS for oil was abolished for rats that received subdiaphragmatic vagal deafferentation. This indicates that the capacity of lipoprivic signals to selectively activate the representations of fat USs may depend on vagal afferent fibers. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

3G网络的QoS估算对运营商战略选择产生的影响

介绍了3G网络的优化和升级技术．以及ACP在天线和心共信道功率方面的应用，并结合实际网络利用动态模拟工具对其使用结果进行了阐述。此外．结论了部署40W（而不是20W）PA等网络升级解决方案的优缺点，以及站点功率共享问题．并介绍了比较结果。     

Characterization and Physical Explanation of Energetic Particles on Planck HFI Instrument

The Planck High Frequency Instrument (HFI) has been surveying the sky continuously from the second Lagrangian point (L2) between August 2009 and January 2012. It operates with 52 high impedance bolometers cooled at 100 mK in a range of frequency between 100 GHz and 1 THz with unprecedented sensitivity, but strong coupling with cosmic radiation. At L2, the particle flux is about 5 \(\hbox {cm}^{-2}\,\hbox {s}^{-1}\) and is dominated by protons incident on the spacecraft. Protons with an energy above 40 MeV can penetrate the focal plane unit box causing two different effects: glitches in the raw data from direct interaction of cosmic rays with detectors (producing a data loss of about 15 % at the end of the mission) and thermal drifts in the bolometer plate at 100 mK adding non-Gaussian noise at frequencies below 0.1 Hz. The HFI consortium has made strong efforts in order to correct for this effect on the time ordered data and final Planck maps. This work intends to give a view of the physical explanation of the glitches observed in the HFI instrument in-flight. To reach this goal, we performed several ground-based experiments using protons and \(\alpha \) particles to test the impact of particles on the HFI spare bolometers with a better control of the environmental conditions with respect to the in-flight data. We have shown that the dominant part of glitches observed in the data comes from the impact of cosmic rays in the silicon die frame supporting the micro-machined bolometric detectors propagating energy mainly by ballistic phonons and by thermal diffusion. The implications of these results for future satellite missions will be discussed.