Advanced Materials Research Vols. 201-203

Abstract: In order to study the juice cooling process after sterilization to obtain the accurate process and reduce the energy used in the cooling, the orange juice in can high temperature short time (HTST) sterilization process was calculated. The maximum temperature of juice in can was defined as 60°C. By using FLUENT, a kind of software which combines hydrodynamics, mathematics and computer technology, we were able to put different fluids into analog computation and numerical experiment to solve problems related to hydrodynamics. Orange juice cooling numerical experiment after HTST sterilization was carried out. The optimization cooling process was obtained: 20°C(293K),14 minutes;15°C(288K),13 minutes; 10°C(283K) ,13minutes; 5°C(278K), 12minutes and 0°C(273K), 12minutes. Using Carnot efficiency in Reverse Carnot cycle, the energy consumption was: 288W, 325W, 348W, 391W, 417W in accordance. And in the result, the optimized process was : 20°C(293K),12 minutes.

Abstract: Biofilm is the most common life phenomenon for microorganisms survived in the nature, which has been recognized in recent years. It is stronger, more and more serious harm to cleared comparing with the resistance of phytoplankton microorganisms.The inside and outside surfaces of food machinery and equipment often becomes the important places for biofilm formation due to improper design flaws or cleaning method. Biofilm formation by many sorts of pathogenic microorganisms in food equipments is a serious food security risk but people are not very aware. According to current research progress on biofilm and its effect on food equipments and food safety, safety design criteria for food machinery were proposed based on food safety and hygiene, food processing technology, mechanical design theory, material science and microbial ecology, with the aim to prevent and reduce the harm of biofilms on food machinery and their products, as well as decrease potential hazards in food safety.

Abstract: To improve accuracy of turbine blades by electrochemical machining (ECM), a new cathode’s feeding method was studied. The rational optimization rules were proposed. Based on the theory of ECM, the blade’s shape evolution was analysed. The influence of the current efficiency brought by the passivating electrolyte, and flow factors influencing the machining process were also considered. According to the rules the cathode’s feeding route was optimized. By using the three-electrode feeding ECM machine, the cathode’s feeding routes can be varied flexibly.

Abstract: The flow state of both the solid and gas phase in the fluidized-bed photo-oxidation reactor for Shenfu coal was studied by cold-model tests. The results showed that the appropriate pipe diameter, particle size of coal, and the coal addition for the gas-solid fluidized-bed reactor were 22 mm, 60-80 mesh, and 10g, respectively.

Abstract: Compared with the traditional rigid pneumatic cylinder, the pneumatic muscle has many outstanding advantages such as large ratio between output force and diameter, large ratio between output force and weight. However, it can only provide the tension, can not provide the thrust force, it is a one-orientation output force component. In this paper, two different diameters pneumatic muscle, combined with the parallel and synchronous toggle force-amplified mechanism,a new type of multi-point press has been innovated. The large-diameter pneumatic muscle will be used for the working stroke of the pressure travel, while the small-diameter pneumatic muscle will be used for the return travel. The tension of the pneumatic muscle will decrease with the increases of the contraction; the force-amplified coefficient of the toggle mechanism will increase with the decrease of the pressure angle, which is taken full account of this complementary relationship between them. So the output force curve of the press is improved smoothly.

Abstract: The grade of the crude hematite-limonite ore is 39.79%. The main metallic minerals are hematite-limonite. Hematite has disseminated structure distributed in the gangue. Limonite was inlayed as stars in hematite. Due to their fine dissemination and close association with gangue minerals, the hematite and limonite particles are hard to be fully liberated, bringing difficulty in their separation. Staged grinding-separation process consisting of high intensity magnetic separation and reverse floatation wag adopted in the beneficiation test on the regionally representative hematite—limonite ore resource. At a grind of 70.0% -200 mesh for the primary grinding and 98.7% -200 mesh for the secondary grinding, the final iron concentrate grade 58.26% and having an iron recovery of 8.33% can be achieved after reverse flotation process test on magnetic concentrate.

Abstract: The monitoring about key components of large wind turbine is important, especially blade. Damages in the material of blade in large wind turbine will cause strain and thus can produce acoustic emission. And this study is presently a new research area in china. This paper refers to the preliminary exploration of common fracture characteristic. Acoustic emission can be used to identify and diagnose the damage. Analyzing the acoustic emission characteristics of the damage in the wind turbine system is emphasized by the experiment. At first, the acoustic emission signals of two different damages and vibration signal of those are compared and analyzed to demonstrate the superiority of the time domain of acoustic emission signals based method for the damage identification. Then, the wavelet is introduced and its characteristics are illustrated. Finally, the wavelet is used to analyze and discuss the time-frequency features of the damage acoustic emission. Some frequency band of wavelets is recomposed, and the results can efficiently extract the features of acoustic emission signal and identify the damage. It offers a valuable reference to monitor the damage about blade of large wind turbine.

Abstract: Foil bearing that has a soft surface is a kind of air bearing. The performances of foil bearings are greatly affected by the materials of bearing surface, which is called foil element. In order to estimate the performance of foil bearings, two kinds of foil thrust bearings that are made of different materials respectively were tested in a micro turbine system, which contains rotation part and static part. Load capacity and stability of these foil thrust bearings were investigated in experiments. The results show that bearing which contains rubber has higher load capacity and bearing which contains copper foil has higher stability. According to the work in this paper, applications with different requirements can adopt suitable foil thrust bearing.

Abstract: By means of wind tunnel tests on the sectional models of Chaotianmen Yangtze River Bridge, some important results are obtained, including the aerostatic force coefficients with the changing of attack angles, and eight flutter derivatives for the bridge deck. The wind-resistant behavior of the bridge is evaluated.

Abstract: Three kinds of low cost shielding materials using boron-containing ores and epoxy as starting materials were developed. The three boron-containing ores consist of natural green ore that is specific in China and the two artificial minerals that are boron-containing iron ore concentrate and boron-rich slag. They were got after natural green ore dressing and separation from blast furnace, respectively. The shielding performance of slow neutron and ⁶⁰Co γ ray among the three shielding materials were compared. The results show that boron-rich slag as neutron absorber performs relative good slow neutron shielding ability, its macroscopic cross section (Σ) is 0.271cm^-1 which is about 1.72 times higher than Lead-Boron Polyethylene B201 whose macroscopic cross section (Σ) is 0.158cm^-1. Boron-containing iron ore concentrate/epoxy composite performs relative good ⁶⁰Co γ ray shielding ability and its linear attenuation coefficient (μ) is 0.0772cm^-1. The elements boron and iron that exist as compound in ore are the main reasons to affect the slow neutron shielding performance. The iron element that exists as compound in the ore has the main attribution to ⁶⁰Co γ ray shielding.