The effectiveness of the United Nations' leakproofness tests

The regulations for the packaging of dangerous goods, which are applicable world-wide for the various modes of transport, include performance tests. It is impossible to conduct laboratory tests for every environmental condition, but the tests can produce a conservative estimate of the situation during transport. This paper analyses the so-called leakproofness test as one of the design-type tests for packagings covered by the United Nations' (UN) recommendations for dangerous goods.     

Industrial leak testing of dangerous goods packagings

The Dangerous Goods Regulations currently do not include limit leakage rates or sensitivity requirements for industrial leak testing procedures that are equivalent to the bubble test, which is the prescribed test method for design type testing of dangerous goods packagings. During series production of such packagings, various methods are used, which often do not meet the requirements of the bubble test with regard to important criteria. Sensitivity, flow direction, pressure level and automatability are particularly important factors when selecting a suitable industrial leak testing method. The following methods are in principle both suitable and equally effective as the bubble test: pressure rise test (vacuum chamber), ultrasonic bubble leak detection and gas detection methods (pressure technique by accumulation and vacuum chamber technique). To ensure a uniform test level during design type testing and production line leak testing and therefore a comparable safety level as required by the Dangerous Goods Regulations, it is necessary to include a more precise specification in these regulations. This requires, on the one hand, information about the sensitivity of the bubble test and, on the other hand, the inclusion of a list of suitable, equally effective industrial test methods with their specific boundary conditions.     

Leakproofness of dangerous goods packagings—comparison of worst‐case limit leakage rates and sensitivity of the bubble test

This work focuses on the question if the bubble test prescribed in the Dangerous Goods Regulations has sufficient sensitivity to detect leakage rates, which could result in the formation of explosive atmospheres during transport. The sensitivity of the bubble test is not directly comparable with other leak testing methods because of its different flow conditions. Therefore, a normalized minimum detectable leakage rate under Helium test conditions is calculated for the bubble test. This sensitivity of the bubble test under reference conditions is compared with limit leakage rates for a worst‐case transport scenario. The sensitivity of the bubble test is not sufficient to prove the limit leakage rates for 6‐L packagings. The formation of explosive vapour‐air‐mixtures cannot be excluded. Therefore, more sensitive leak testing methods should be considered for smaller packaging design types.     

Aspects of Packaging from NDA <- IND

The strategic decisions regarding package stability in an NDA should be thought out even before the IND stage (hence the inversion of the order of the words NDA and IND in the title). The philosophy of clinical blister packaging is discussed as are the tests necessary to ensure perfection of seal. The principles of molecular and pinhole moisture permeation are discussed. Suggested fractional factorial schemes for package testing are presented     

利用真空衰减法测试预包装食品的密封性

目的 预包装食品的密封性关系到食品质量与安全。本文针对预包装食品目前普遍采用水检气泡法时灵敏度不足的问题,采用真空衰减法检测食品包装的密封性。方法 分别利用2种不同检测技术对市面上55款预包装食品样品进行密封性检测,并根据包装类型、封合方式、包装规格等不同分类方式将测试数据进行综合比较分析。结果 水检气泡法测试成本低,可明显地指示出泄漏位置,但方法灵敏度较低,且无法准确定量;真空衰减法可在不破坏原有包装的情况下,大幅度提高检测灵敏度,并得到定量数据,但无法准确指示泄漏点位。结论 真空衰减法可以作为水检气泡法的有效补充方法在实际工作中使用。     

Aspects of Packaging from NDA <– IND

Abstract

The strategic decisions regarding package stability in an NDA should be thought out even before the IND stage (hence the inversion of the order of the words NDA and IND in the title). The philosophy of clinical blister packaging is discussed as are the tests necessary to ensure perfection of seal. The principles of molecular and pinhole moisture permeation are discussed. Suggested fractional factorial schemes for package testing are presented     

The tightness of retail packaging: A selection of test methods to be used for a wide range of packed products

The tightness of retail packagings and of their closures is of primary importance both for domestic and industrial products. For this reason, a research programme designed to establish proper testing methods for a wide range of ‘packaging + product’ combinations, in order to check their tightness or permeability, was set up. All the available testing methods were reviewed, the most reliable ones selected and their sensitivity determined. More than 200 combinations of ‘packaging + product’ belonging to five families of consumer products were examined and their tightness/permeability problems noted. Finally, specific testing methods were assigned to each combination of ‘packaging + product’. All these examples are currently in use in the packaging laboratory as a guideline for the testing of every kind of packaging.     

C楞瓦楞纸板动态缓冲模型及应用

利用万能试验机和跌落试验台分别得到C楞瓦楞纸板静态、动态应力-应变数据,建立相应的理论模型,并用最小二乘法识别模型中的参数。给出了瓦楞纸板在缓冲动力学中应用的例子,结果表明所建立的缓冲模型,可以直接用于缓冲包装设计,克服了用最大加速度-静应力曲线来设计缓冲包装需要大量实验和较多的数据的弊端。     

An experimental study of bubble behavior in a temperature gradient near a heated wall under low-gravity and microgravity conditions aboard NASA DC9 airplane

The behavior of a single bubble and a pair of bubbles under microgravity conditions has been investigated using the NASA-DC9 aircraft in order to understand the effects of various parameters and to control the bubble behavior in space. Silicone oil was used as the test liquid, and a nitrogen gas bubble was injected from the top wall under different experimental conditions. In an isothermal case, two different microgravity conditions were achieved by either fixing the experimental apparatus to the aircraft floor or freely floating the apparatus in the aircraft cabin. The bubble behavior was found to be clearly influenced by the quality of the microgravity environment, and variations of the bubble aspect ratio with the Bond number were presented. The results indicate that there is a critical Bond number of the order of 10⁻¹ which determines the bubble shape deformation. In the free-floating experiments, a temperature gradient was imposed on the liquid around the bubble near the heated top wall. Marangoni convection was expected to occur around the bubble and the bubble behavior was studied under various temperature gradients. The bubble aspect ratio was found to decrease with an increase in the Marangoni number. A theoretical model for the relation between the Marangoni flow around the bubble and the aspect ratio is proposed based on simple assumptions. Visualization of Marangoni convection around the bubbles using the photochromic dye activation method was successfully performed. The aspect ratios predicted by the model agreed with the experimental results reasonably well. Direct measurements of surface velocity are, however, necessary to further evaluate the validity of the model.     

Developments in plastics packaging for the transport of dangerous goods

Several interesting developments in plastics packagings and intermediate bulk containers (IBCs) for the transport of dangerous goods are of importance. Significant developments include the application of new materials and packaging concepts, the increasing re‐use of packaging and the possibility of the application of recycled material. How these developments have influenced or should influence the UN recommendations and regulations on the transport of dangerous goods is discussed. Further, the role of CEN and ISO standards, which are under development, is indicated. In this context, the European project CHEMPACK funded by the EC within the framework of the Standards, Measurements and Testing programme, is outlined. This project is executed in cooperation with raw materials manufacturers, packaging/IBC manufacturers and research institutes, and is coordinated by TNO. The aim of the project is to develop harmonized test methods and procedures for the assessment of the chemical compatibility of plastics packagings and IBCs. Copyright © 1999 John Wiley & Sons, Ltd.     

Experimental Investigations Concerning the Sensitivity of the Leakproofness Test for Dangerous Goods Packagings Relating to the Leak Diameter

The objective of this experiment was to verify that in regards to the leakproofness bubble test for packagings of dangerous goods, a reduction of the air overpressure from 0.2 to 0.1 bar can be compensated for by reducing the water surface tension to a value of approximately 33.2 mN/m by adding a wetting agent. It was experimentally proven that this method will yield the same leak diameters. This is important to avoid irreversible deformations during the leaktesting of intermediate bulk containers (IBCs) while using a test overpressure of 0.2 bar. Bubble test experiments were carried out on artificial borehole‐shaped leaks manufactured of two different materials high density polyethylene (HDPE) and stainless steel by ultrashort pulse laser technology and with two different immersion test liquids (deionized water and a 0.1% Lutensol FSA fabric softener active 10 solution). The characteristic diameters of the boreholes investigated were from 11.5 to 30.3 µm in length. Copyright © 2013 John Wiley & Sons, Ltd.     

乘客安全气囊工厂包装件的改进探索

目的采用改进包装的方式降低乘客安全气囊(PAB)工厂包装件的运输危险性。方法依据乘客安全气囊在联合国外部火烧试验(UN6c试验)的结果,结合LS-DYNA动力有限元软件的分析,先后采用网格式和条栅式金属丝网笼包装控制金属迸射物的产生。结果条栅式金属丝网笼包装成功束缚了所有动能大于8 J和动能大于20 J的金属迸射物,使乘客安全气囊工厂包装件成功通过了联合国外部火烧试验。结论改进后的包装符合联合国关于危险货物运输的建议书(TDG)中对危险品包装的有关要求,将原分类为第1类(爆炸品)的乘客安全气囊工厂包装件降低为第9类(杂项危险品),使乘客安全气囊(PAB)工厂包装件适合更多形式的运输。     

Planning constant-stress accelerated life tests with multiple stresses based on D-optimal design

With the rapid technological advances, products are becoming more reliable. Then, multistress accelerated life testing (MALT) has been adopted in engineering to obtain failure information in a limited time. In order to make the testing procedure more efficient, it is necessary to better design the test plan. However, to date, relevant research on planning of MALT is limited. Multiple stresses will lead to plenty of stress-level combinations that require too much cost and time to implement. Besides, there may be interactions among multiple stresses, which need more experiments for parameter estimation. To solve these problems, we propose a novel planning method for constant-stress MALT under lognormal distribution using D-optimal design, which can reduce required test points efficiently and deal with second-order effects in models. In ALT, the log-linear model is often used to describe the life-stress relationship. Hence, D-optimal design is adopted in this paper to select test points from the whole test region. Then, optimal unit allocation plans are formulated under V/D-optimality criterion, respectively, where type I and type II censoring are both discussed. A real case of light-emitting device (LED) is presented to compare the proposed approach with other two existing methods. The results show that the proposed method performs better than other two existing methods both in prediction accuracy and estimation precision. Moreover, a sensitivity analysis reveals the robustness of the optimal plans determined by the proposed method.     

Use of a pinhole to develop an active packaging system for kimchi,a Korean fermented vegetable

A pinhole in a packaging system for kimchi, a Korean lactic acid fermented vegetable, was found to actively modify the headspace gas and improve the quality of the product. The effect of the presence of a pinhole on the headspace atmosphere and microbial flora was investigated in the packaging system and a prototype of this active packaging system was fabricated and tested for its effectiveness in improving quality. The incorporated pinhole eliminated pressure build-up in the package by allowing restricted flow of gas to the atmosphere. O₂ and N₂ gases in the headspace were flushed out by CO₂ gas produced continuously from lactic acid fermentation and this modified atmosphere enhanced the growth of lactic acid bacteria. In particular, the growth of Leuconostoc species, heterofermentative lactic acid bacteria, was promoted by the pinhole. The increased amount of heterofermentative lactic acid bacteria led to a higher accumulation of CO₂ in the package and this provided the kimchi with a stronger cool carbonic taste and a desirable flavour. An elaborate design of the pinhole incorporating microporous film and a gas adsorvent could be adopted to improve the kimchi packaging system by preventing leakage of fermentative aroma and possible contamination from outside atmosphere. © 1997 John Wiley & Sons, Ltd.     

Numerical Simulation of Taylor Bubble Formation in Micro-channel by MPS Method

Moving Particle Semi-implicit (MPS) method uses particles and their interactions to simulate incompressible flow and it is a promising meshless method for multiphase flow simulation. In order to simulate the micro-bubble generation in micro-channel, surface tension model in MPS is improved by introducing fourth order central difference scheme for the calculation of unit normal vector. Numerical results for the oscillation of macro and micro droplets are in good agreement with theoretical prediction, which confirmed the validation of our model. By introducing the improved surface tension model into MPS method, the micro-bubble generation in T-shaped micro-channel was simulated successfully. The reasonable agreement between numerical simulations with visualization experiment confirmed the capacity of MPS with the improved surface tension model for the microgravity or micro-scale two-phase flow, which is dominated by surface tension effect. Finally, micro-bubble generations in different micro-channels are simulated. It is found that bubble size will decrease with increasing liquid flow rate and increase with increasing gas flow rate. Compared with 45° bifurcation micro-channel, T-shaped micro-channel can generate bubble smaller and faster.     

Using pinholes as tools to attain optimum modified atmospheres in packages of fresh produce

A mathematical model for the gas flow through a pinhole applying the Stephan–Maxwell laws was tested and used in estimating the atmospheric change in a cut onion package. The effects of pinhole variables such as length, number and diameter on the package atmosphere were then calculated from the model. Established mathematical model equations could well predict the changes in gas composition in packages by taking into consideration the end effect of pinholes. Modification of the package atmosphere was found to be strongly affected by the dimensions and number of pinholes in the packaging. Longer pinholes with smaller diameters accelerate modification of the package atmosphere to lower O₂ and higher CO₂ concentrations. The number of pinholes highly influences the degree the atmosphere is modified inside the package when their length is short, while increased pinhole length significantly decreased the dependence of the atmosphere on the number of pinholes. If the variables of pinhole dimension and number are combined with variety of permeable films it is possible to design a package for cut onions which, it is calculated, should create and maintain an optimum atmosphere in the range of 2–8% O₂ and 5–15% CO₂. © 1998 John Wiley & Sons, Ltd.     

Industrielle Dichtheitsprüftechnik ohne Testgas nach dem Massenspektrometerprüfverfahren

Environmental concerns, product safety and quality assurance systems (ISO 9000) demand highest leakproofness of components. A leak test methol which bases on the mass spectrometer test method is in practical service since 3 years under production conditions (some thousend tests per day), for fully automatic testing and leak rate ranges of 10^?3cm³/s. Ambient air is used as “testgas”. Specific applications for the packing industry as well as the automotive industry are described.     

基于ISTA测试的小型非易碎品包装方法的标准化研究

目的 对小型非易碎品在分拨中心的二次包装方法进行标准化研究,以应对物流中的过度包装问题.方法 在问卷调查与实地调研的基础上,统计分析包装材料使用数量和包装方法;并应用鱼骨图进行影响因素分析,提出小型非易碎品二次包装标准化方法;最后参照ISTA测试,进行振动测试、跌落测试,从而确定包装间隙率的阈值、充气袋放置数量、气泡膜全方位包裹圈数.结果 采用文中提出的标准化包装方法,能够在确保商品运输安全性的同时,节省充气袋使用量62.3％,气泡膜用量80.8％.结论 能有效解决小型非易碎品物流配送过程中的过度包装问题.     

Maximum Gauge Pressure in Dangerous Goods Packagings Under Normal Conditions of Carriage – Comparison of Direct Measurement and Calculation

The objective of this work was to determine the maximum gauge pressure in the vapour phase above the liquid in different design types of dangerous goods packagings under normal conditions of carriage. The design types investigated were steel and plastic packagings with a volume of approximately 6 l. Two different methods were applied. In method 1, the pressure inside the packaging filled with a certain filling substance (dichloromethane) was directly measured under simulated conditions of carriage (degree of filling: 90%; filling temperature: 15°C; temperature during storage: 31°C). The maximum measured gauge pressures were between 89 mbar for a light plastic jerrican and 336 mbar for a steel drum. In method 2, the gauge pressure was calculated. The consideration of a rigid packaging combined with the assumption of a vapour pressure of zero during filling and sealing can serve as a worst case scenario. The calculated gauge pressure is approximately 1061 mbar. This procedure leads to the highest safety factor and does not require any experimental investigations. For a more realistic approximation of the gauge pressure of a non‐rigid packaging, a packaging‐specific function of relative expansion can be used, which is determined by a hydraulic pressure test. The calculated values ranged from 105 to 347 mbar. Method 2 provides conservative results. No hazardous filling substance is needed, and it allows a prediction of gauge pressure for other temperatures, substances and filling degrees. Therefore, this method could serve as alternative to UN Model Regulations 6.1.5.5.4 (a). Copyright © 2014 John Wiley & Sons, Ltd.     

基于判别分析与ANN的药品铝塑包装泡罩XRF分析

目的针对案件现场常见的药品铝塑包装泡罩,为达到对其分类识别的目的,提出系列检验分析、数据处理方法。方法采用X射线荧光光谱法对45个药品铝塑包装泡罩样本所含元素进行检验并讨论分析。对检验结果进行无监督的系统聚类,利用离差平方和法计算欧氏距离进而将未知样本分为5类。结果将分类结果作为变量进行判别分析,选取累积方差百分比为97.8%的2个判别函数,其类内平方和与总平方和之比为0.015和0.394,具有较强的解释能力。绘制的样本判别分类图将5类样本类之间相互区分开来,样本总体判别正确率为95.6%。提取样本在判别函数上的判别得分构建了人工神经网络,最终分类正确率为97.8%。结论利用X射线荧光光谱法对药品铝塑包装泡罩进行检验,将元素种类及含量作为变量进行了分类,并构建了45个药品铝塑包装泡罩样本的人工神经网络分类模型,可借助该模型进一步实现对于案件现场未知类别的药品铝塑包装泡罩样本的分类识别。