Methylene-blue-sensitized dichromated gelatin holograms with antihumidity polymer coatings

An efficient method of resisting humidity for methylene-blue-sensitized dichromated gelatin (MBDCG) holograms is reported. The method uses a viscous liquid pure poly(styrene) solution with a low degree of polymerization as the coating material. On the basis of this coating, the diffraction efficiency of treated MBDCG holograms exposed to a high-humidity (relative humidity of 80-85%) environment was not obviously changed during observation over 3 mon.     

Methylene blue dichromated-gelatin holograms: antihumidity method for taking off strongly adsorbing humidity groups

A new, to our knowledge, method of modifying methylene bluedichromated-gelatin (MBDCG) holograms by use of ninhydrin andremoval of their amino groups and carboxyl groups, which stronglyadsorb humidity, has been developed. The modified MBDCG hologramsare stable for 1000-line/mm gratings (diffractional efficiency of95%) in a high-humidity environment (relative humidity of80%-85%). The modifying reaction does not affect thediffraction efficiency of the MBDCG holograms. It is demonstratedthat the amino groups and carboxyl groups of the side chains in thegelatin do not undergo the chelation reaction with Cr iii in the sensitive area.     

冷冻诱导相分离法制备大孔羧甲基壳聚糖基高吸水树脂

探索了冷冻诱导相分离法制备具有大孔结构的高吸水性树脂的方法。将羧甲基壳聚糖基高吸水树脂在水中溶胀并冷冻后,通过冷冻干燥的方法制得了具有大孔结构的高吸水树脂,这类树脂具有较快的吸水速率。研究了凝胶浓度、预冻温度、溶胀时间和明胶含量等反应条件对所制备树脂结构及溶胀动力学的影响。     

Acid Ossein Gelatin

Abstract

The properties and manufacture of acid ossein gelatin are discussed with particular reference to the use of acid ossein gelatin in the photographic and allied industries.

The effect that the demineralizing process has on the properties of the gelatin extracted has been investigated with different demineralizing media. Loss of amide ammonia during the commercial demineralizing of bone has been confirmed and the rate of this toss has been studied using calcium and ammonia analyses. Different types of acid or lime processed gelatins can be distinguished also by analysis of their titration curves. From both experimental and calculated titration curve data, some correlations are found xvith gelatin amide content and isoelectric point.

A literature review is given, highlighting some of the applications found for acid ossein gelatin in the photographic industry.     

Gelatin layers for holographic purposes: an X-ray diffraction study

In order to overcome uniformity problems in large u.v. holoconcentrators recorded in dichromated gelatin, the structure of hardened gelatin layers has been studied. X-ray diffraction patterns show that layers are formed by individual gelatin chains partly associated as triple-stranded helical rods as those found in native collagen. These rods, in turn, may form fibrillar aggregates. Helical rods and microfibrils are, to a great extent, parallel to the layer surface and their relative amount and packing depend on the hardener as well as on temperature and drying time after coating. X-ray diffraction offers the possibility of estimating in a simple manner the relative amount of triple-helical rods in crystallographic register within the gelatin layers. From these results, a method for obtaining uniform large holograms by means of a slow layer drying process is proposed.     

Change in the Molecular Weight Distribution of Gelatin by a High Pressure Slurry Jet

Abstract

Physical and photographic properties of gelatin depend on the molecular weight distribution of the gelatin, which it is important to control. We controlled the molecular weight distribution of gelatin by pressurizing the sample gelatin solution and jetting it at high velocity from a nozzle to a collision plate. II was found that this method teas effective in controlling the molecular weight distribution of gelatin and in preparing a gelatin which contains mainly ± and β components and few high and low molecular weight components.     

Effect of Process Variables on the Microencapsulation of Vitamin A Palmitate by Gelatin-Acacia Coacervation

Microcapsules of vitamin A palmitate were prepared by gelatin-acacia complex coacervation. The effects of colloid mixing ratio, core-to-wall ratio, hardening agent, concentration of core solution, and drying method on the coacervation process and the properties of the microcapsules were investigated. The microcapsules of vitamin A palmitate were prepared using different weight ratios of gelatin and acacia, that is, 2:3, 1:1, and 3:2 under controlled conditions. The other factors studied were 1:1, 1:2, and 1:3 core-to-wall ratios; 30, 60, and 120 min of hardening time; 2, 5, and 10 ml of formaldehyde per 280 g of coacervation system as a hardening agent; and 30%, 40%, and 50% w/w vitamin A palmitate in corn oil as a core material. The drying methods used were air drying, hot air at 40°C, and freeze-drying. The results showed that spherical microcapsules were obtained for all conditions except for 30 min of hardening time, which did not result in microcapsules. The optimum conditions for free-flowing microcapsules with a high percentage of entrapped drug were 1:1 gelatin-to-acacia ratio and 1:2 core-to-wall ratio when hardening with 2 ml formaldehyde for 60 min and using 40% w/w vitamin A palmitate in corn oil as the core concentration. In addition, drying the microcapsules by freeze-drying provided microcapsules with excellent appearance.     

Effect of process variables on the microencapsulation of vitamin A palmitate by gelatin-acacia coacervation

Microcapsules of vitamin A palmitate were prepared by gelatin-acacia complex coacervation. The effects of colloid mixing ratio, core-to-wall ratio, hardening agent, concentration of core solution, and drying method on the coacervation process and the properties of the microcapsules were investigated. The microcapsules of vitamin A palmitate were prepared using different weight ratios of gelatin and acacia, that is, 2:3, 1:1, and 3:2 under controlled conditions. The other factors studied were 1:1, 1:2, and 1:3 core-to-wall ratios; 30, 60, and 120 min of hardening time; 2, 5, and 10 ml of formaldehyde per 280 g of coacervation system as a hardening agent; and 30%, 40%, and 50% w/w vitamin A palmitate in corn oil as a core material. The drying methods used were air drying, hot air at 40°C, and freeze-drying. The results showed that spherical microcapsules were obtained for all conditions except for 30 min of hardening time, which did not result in microcapsules. The optimum conditions for free-flowing microcapsules with a high percentage of entrapped drug were 1:1 gelatin-to-acacia ratio and 1:2 core-to-wall ratio when hardening with 2 ml formaldehyde for 60 min and using 40% w/w vitamin A palmitate in corn oil as the core concentration. In addition, drying the microcapsules by freeze-drying provided microcapsules with excellent appearance.     

低碳钢丝焊网热镀锌工艺的改进

根据低碳钢热镀锌原理,分析了低碳钢钢丝焊网热镀锌工艺中存在的问题,包括工艺不完善、锌液成分不合理、镀后抹拭材料及方法不当等而导致的热镀锌层质量不稳定、锌耗高.针对上述问题,提出了相应的改进方法,包括采用复合除锈剂进行酸洗除锈,强化除锈效果;以氯化锌与氯化铵比例为1.2～1.6、总浓度为12%～15%的混合溶液代替单一的氯化铵作为助镀剂;增加助镀后的烘干工序;采用无机物和珍珠岩混合材料作为抹拭剂等改进措施.通过改进与完善工艺,所得镀锌层表面光滑,焊接点处无积锌,锌耗比工艺改进前降低2%.     

Mechanical Properties of Gelatin Film

Abstract

The mechanical properties of gelatin films were investigated. We prepared gelatin films under various conditions, such as changing temperature, storage time and humidity. The stress-strain curves were obtained by measuring the tensile-strength of sample films at various humidities. These results suggest that mechanical properties of gelatin films depend on the structure and water content of the sample. It was found that the structure of gelatin films was influenced by the drying process and the thermal history of the gelatin.     

真空冷冻干燥机内的水蒸气压力分布计算

试图从冻干过程中冻干室内水蒸气压力分布不均匀的角度,分析解释大型真空冷冻干燥机存在的不同部位物料干燥速率不均匀问题.通过建立描述搁板层间通道和搁板组间抽气通道内水蒸气流动的数学模型,计算得出流动通道内的水蒸气压力分布规律.定义了2个通道特征系数,反映出冻干机结构、工艺参数对水蒸气压力分布的影响作用.计算结果可以用于估算冻干机内不同部位物料的干燥速率,并可为确定冻干机关键结构工艺参数提供重要的理论参考依据.     

The Role and the Effect of Calcium Ion Content of Photographic Gelatins on Coating Defects

The influence of the calcium ion content of some photographic gelatins on the adhesion of gelatin solutions to emulsion layers was investigated by surface tension, pH and viscosity measurements and by coating using the dip method.

Adhesion of the gelatin layers was examined in the coating process under the following conditions:

Surface tension at varying wetting agent concentrations, for gelatin solutions which contain calcium ions from 0 to 5760 ppm concentration.

Surface tension at varying gelatin concentrations.

Surface tension at varying pH values of the gelatin solutions used in the coating process.

The experimental results demonstrate that, at gelatin concentrations between 2 and 4%, the adhesion ability of a gelatin solution on a dry or wet gelatin (emulsion) layer depends on the Ca2* content of the coating solution. It is necessary to have at least 1000 ppm Ca2* concentration to guarantee a perfect adhesion and a perfect coating. Gelatin source, pH and the viscosity of the system are unimportant.     

Plate and Frame Filtration in Photographic Gelatin Manufacturing—Some Practical Considerations

Abstract

Gelatin filtration is a required operation in all photographic gelatin manufacturing facilities. For lime-processed bovine bone gelatin, many different filtration methods can be used, one of which is plate and frame filtration. The successful operation of plate and frame equipment depends on a good working knowledge of, and careful adherence to, good filtration practices. Careful choice of a filter medium is also important. This paper outlines many of the practical considerations gelatin manufacturers should think about when setting-up and operating plate and frame equipment, and choosing filter media.     

液混式膨化硝铵炸药生产技术研究

文章研究液混式生产工艺制备膨化硝铵炸药。将86%-94%的氧化剂硝酸铵与可燃剂复合油相于100-120℃,在液态状态下进行混合,得到悬浮状混合分散体系,再采用连续真空干燥工艺,脱除体系中的水分,制得了高性能膨化硝铵炸药。论文讨论了年产2万吨液混式膨化硝铵炸药生产线的工艺流程、设备设计和生产过程控制,这对指导生产线建设和生产过程产品质量控制具有重要的现实意义。     

A microcylindrical lens array made of silver-halide-sensitized gelatin etched by an enzyme with a real-time mask

Abstract

A novel method has been developed to fabricate microcylindrical lenses by etching silver-halide-sensitized gelatin (SHSG) with an enzyme solution, and the exposure pattern is produced on SHSG through a real-time mask technique. In this paper the principle of etching SHSG with an enzyme solution is given in detail and the optimum technique parameters of this process are presented; furthermore the theoretical analysis and solving scheme for the nonlinearities which arise from the absorption of light energy by film are given. A good linear relationship is experimentally obtained between the etching depth and time in depth a range up to 4 μm. Finally, the microcylindrical lens is achieved by experiment. The results are evaluated for experiments with a stylus profiling instrument and scanning electron microscope. This method does not require the use of expensive equipment, and it is not sophisticated and time consuming. So it is a practical method to fabricate excellent micro-optical elements.     

A variance propagation algorithm for stochastic heat and mass transfer problems in food processes

A variance propagation algorithm for stochastic coupled heat and mass transfer problems subjected to first order autoregressive random process boundary conditions was developed. The algorithm is based on the finite element formulation of Luikov's coupled heat and mass transfer equations and involves the numerical solution of coupled Lyapunov and Sylvester matrix differential equations. It offers a cheap alternative to the Monte Carlo method for the computation of the mean value and variance of the temperature and moisture content field. The algorithm is generally applicable and can easily be inserted in any existing finite element code. Also, it can be extended to other types of random processes. The algorithm was applied to analyse the drying of a soybean kernel. Simulation results show that random fluctuations of the process conditions may cause considerable variability of the temperature and the moisture content within the drying soybean kernel. This is an important feature to take into account for the design of a drying process, and for thermal food processes in general. Copyright © 2001 John Wiley & Sons, Ltd.     

Preparation of microcapsules that produce color in response to humidity for use in intelligent functional paper

In this study, a microcapsule that produces color in response to moisture in air was produced for use in an intelligent functional paper which is able to self-color after a fixed time. This microcapsule containing FeSO₄ as the coloring material was prepared from gelatin and terephthaloyl chloride by an interfacial polymerization technique and was modified by a 2-propanol solution of glycerin to supplement the moisture sensitivity. A microcapsule membrane was formed by crosslinking between the amino group at the end of the gelatin and the carbonyl group of the terephthaloyl chloride. The time required for the microcapsules to produce the color tended to increase with decreasing amounts of the glycerin 2-propanol solution used for the soaking treatment of the microcapsules or increasing amounts of FeSO₄ in the microcapsules.     

Bioactive microspheres produced from gelatin–siloxane hybrids for bone regeneration

In this study, we produced a novel microsphere with a hybridized composition of gelatin and siloxane which is bioactive and degradable for the applications in bone regeneration fields. A solution of gelatin organic and siloxane inorganic containing calcium chloride was formulated into microspheres in an oil bath mediated by a surfactant. Following the processes of hydration, gelation and solidification, well-shaped spherical particles were produced with sizes of a few to hundreds of micrometers (68 μm on average). The obtained microspheres were highly stable in an aqueous solution due to the in situ cross-linking of the siloxane with gelatin chains, which eliminated the additional cross-linking step generally used in pure gelatin. The hybridized microspheres exhibited rapid induction of apatite-like crystals on their surface with incubation in a simulated body fluid, suggesting an excellent bone bioactivity in vitro. It is considered that the newly developed organic–inorganic microspheres may be useful for the regeneration of skeletal defects.     

Methoxybutropate microencapsulation by gelatin-acacia complex coacervation

Microcapsules of methoxybutropate solid particles or of an oily saturated solution of the same drug were prepared by complex coacervation between gelatin and acacia and dried with three different methods: isopropanol addition, spray-drying, and freeze-drying. Successively, microparticles were analyzed by infrared thermobalance, ultraviolet (UV) spectroscopy, optical and scanning electron microscopy, and sieves to find out parameters such as yield, moisture content, encapsulation percentage, morphology of solid particles, and particle size. Results highlighted that the most appropriate drying method for industrial purposes was spray-drying, particularly for oil-containing microcapsule formulations.