Precision powder metering utilizing fundamental powder flow characteristics

A proof of concept prototype has been constructed to test the capabilities of using vibration frequencies determined from rotating drum powder flow characterization to reproducibly fill small unit doses of pharmaceutical powders. A lactose excipient was characterized in the rotating drum and a multiperiodic vibration signal determined. Doses ranging from 1.5 to 16 mg were metered from the system. The prototype used vibrational fluidization to meter powders under the influence of gravity. Vibration frequencies calculated from physical characterization of the powders had a significant influence on the reproducibility of metering with relative standard deviations around the mean as low as 2% and no greater than 5%. Future work will address limitations to the system that introduced systematic errors and will address additional formulation variables.     

Addition of cashew tree gum to maltodextrin-based carriers for spray drying of cashew apple juice

This study involved an attempt to totally or partially replace maltodextrin DE10 (MD10) by cashew tree gum (CTG) as a drying aid agent in spray drying of cashew apple juice. The objective was to evaluate the impact of drying aid/cashew apple juice dry weight ratio (D/C, ranging from 3 to 5) and degree of replacement of MD10 with CTG (CTG_R, ranging from 0% to 100%) on ascorbic acid retention (AAR), hygroscopicity, flowability and water solubility of spray dried cashew apple juice powder. AAR was increased from 72.90% to 95.46% by increasing D/C from 3 to 5. CTG was shown as a promising maltodextrin replacer, being more effective than the latter to decrease powder hygroscopicity. The most adequate drying conditions (D/C = 5, CTG_R≥50%) resulted in more than 90% of AAR, and produced a powder with good flowing properties and water solubility.     

The influence of powder morphology on the effect of rosemary aroma microencapsulation during spray drying

The influence of particle morphology of spray dried powders obtained by using different carriers on the efficiency of microencapsulation of rosemary aroma is shown in the present research. It was found that the type of the carrier influenced the size but not the shape of rosemary aroma capsules and all the capsules were spherical with cracks. The biggest particles, d₅₀ = 55 μm, were obtained with 25% maltodextrin (MD) as a carrier, and the smallest, d₅₀ = 29 μm with 30% gum arabic (GA). The efficiency of encapsulating aroma inside of the capsules depended on the particles size and apparent density. An increase in the quantity of microencapsulated aroma from 10% for 25% MD to about 60% for 30% GA as the carrier was seen, which co‐related with a decrease in the average diameter of the powder particles. Similarly, an increase in the efficiency of aroma retention was followed by an increase of apparent density of powders from 796 (25% MD) to 1156 kg m^?3 (30% GA).     

DEHYDRATION BY DESORPTION AND BY SPRAY DRYING OF DAIRY PROTEINS: INFLUENCE OF THE MINERAL ENVIRONMENT

A drying method by desorption in a water activity meter was used to simulate the conditions of spray drying and to determine the water transfer inside dairy concentrates towards the surface and from the surface to the drying air. The concentrates were also spray dried and solubility index of powders were determined during reconstitution. Whey protein concentrates (WPC) and native phosphocaseinate suspensions (NPCS) were used to study the effect of NaCl (420 mM), CaCl₂ (222 raM), sodium phosphate (173 mM) and sodium citrate (238 mM) on the water transfers. The decrease in water transfer during drying was explained by the high hygroscopicity of added mineral salts to WPC. NaCl addition to NPCS decreased the water transfer during drying, but increased the solubility index. Citrate and phosphate addition to NPCS increased the water transfer during drying and reconstitution. CaCl₂ increased the water transfer during drying but the solubility index was always low. Results are discussed as a function of the aqueous environment, of the nature of mineral salts, of the structure of dairy proteins and of protein solvation.     

喷射沉积Cu－Pb合金的研究

研究了由Ｏｓｐｒｅｙ工艺制取的喷射沉积Ｃｕ－２４Ｐｂ－１Ｓｎ合金板坯的显微结构、弯曲断口的表面形态和冷轧变形对合金密度的影响。结果表明：喷射沉积合金的铅相细小且均匀分布，消除了宏观偏析。冷轧后，板坯的相对密度可由沉积态的９６％提高到１００％。本文还讨论了合金的重力偏析和喷射沉积过程的液－团相比率控制问题。     

喷镀热解制备SnO2：F透明导电热反射膜

SnCl_4·5H_2O和SnF_2的水溶液经超声振荡雾化后喷射到高温平板玻璃衬底上热解形成掺氟二氧化锡(记作SnO_2∶F)透明导电热反射膜。喷镀时的衬底温度对膜的微观结构起决定作用。衬底温度300℃时形成非晶膜,高于400℃时形成多晶膜且结晶度随衬底温度升高而提高。结晶度高的多晶膜导电率达10~3Ω~(-1)cm~(-1),镀有多晶膜的玻璃对可见光(0.3～0.8μm)的透过率比未镀膜的玻璃仅减少10％左右,而红外(2～10μm)反射率比未镀膜的玻璃提高近4倍。膜的这种电学和光学特性与结晶程度有明显的对应性。     

A NOVEL MULTI-LAYER SPRAY DEPOSITION TECHNOLOGY

ＡＮＯＶＥＬＭＵＬＴＩ－ＬＡＹＥＲＳＰＲＡＹＤＥＰＯＳＩＴＩＯＮＴＥＣＨＮＯＬＯＧＹＣｈｅｎＺｈｅｎｈｕａ；ＨｕａｎｇＰｅｉｙｕｎ；ＪｉａｎｇＸｉａｎｇｙａｎｇ；ＷａｎｇＹｕｎ；ＰｅｎｇＣｈａｏｑｕｎ（ＲｅｓｅａｒｃｈｉｎｓｔｉｔｕｔｅｏｆＮｏｎ－Ｅ...     

Influence of testing parameters on the corrosion rate of magnesium alloys

In sodium chloride solutions alloy composition, phases, microstructure and grain size influence the corrosion behaviour of magnesium alloys. Concentration and distribution of the critical impurities iron, nickel and copper affect the corrosion performance strongly. Salt spray tests according to ASTM B 117 or DIN 50021 are used to control quality of magnesium alloys. Results of these tests often estimate alloy subcontractors and are therefore very important to placing. Standards specify test solution, test temperature and position of specimens during test in the salt spray chamber. Standards not prescribe preparation of test specimens, exposure period, handling of the specimens after salt spray test nor the interpretation of the results. Results of salt spray tests can be only compared, provided that test conditions are exactly given. Whether the standards fulfil the above described criteria, will be shown by extensive investigations. Therefore the influence of exposure period, surface condition and microstructure was investigated.     

喷涂、喷焊和堆焊材料

简要介绍了喷涂、喷焊和堆焊材料的发展、应用和对于国民经济的重要意义。     

离心喷雾干燥机的调试及现场问题的处理

介绍LPG-50型高速离心喷雾干燥机的调试过程并分析在调试过程中出现的问题与解决的方法。