Comparative Carbon Footprint of Packaging Systems for Tuna Products

The present study aimed to evaluate and compare the carbon footprint associated with canned tuna meat with a focus on packaging systems used to provide one single‐serve meal. The manufacturing process of retort pouches and cups produced 60% and 70% less greenhouse gas emissions, respectively, than that of metal cans. However, the overall carbon footprint of canned tuna in retort cups was 10% and 22% less than when packaged in metal cans and retort pouches, respectively. Packaging and its associated processing constituted significant fractions of the product's carbon footprint, ranging from 20% to 40%. Hotspots in the life cycle assessment of canned tuna are packaging production and disposal and product sterilization. The improvement of retort operation in terms of capacity and energy utilization and the efficiency of post‐consumption packaging material recovery are the key factors responsible for the reduction of a product's carbon footprint. These issues present a challenge to both the food industry and the local authorities. Copyright © 2011 John Wiley & Sons, Ltd.     

Predictive mechanical performance evaluation of consumer food cans using stereolithography models

The development of new metal food containers can be a technologically challenging and costly process. Understanding the interplay between the major design characteristics and requirements affecting the product's final structural capability is paramount to achieving an optimum design proposition. As a result, computer‐based simulation has been employed by industry to assess a container's performance under a variety of load conditions, including axial load and panelling of cans. In this paper, the feasibility of a new approach for addressing the effects of design parameters on the structural performance of containers under development is investigated. The evaluation methodology is based on structural testing of stereolithography‐built physical prototypes of a rigid metal container used for coffee packaging. It is shown that the experimentally obtained findings are in accordance to those resulting from computational simulation. This method can be used to support the development of existing and new metal containers. Copyright ©2003 John Wiley & Sons, Ltd.     

Effect of Surface Free Energy of Film Laminated Steel Sheets on Content Release Properties

Polyethylene terephthalate (PET) sheets that are now widely used in beverage cans have excellent properties of formability, corrosion resistance and adhesion to steel sheets. To expand their application, we have sought to develop a new PET film laminated steel sheet for use in food cans. Content release properties are necessary for easy removal of the can contents in food can applications. However, PET film laminated steel sheets have poor content release properties. Investigations of these properties have revealed dependence on the strength of adhesion between the films and can contents. The surface free energy of PET films has been inferred to be the main factor in poor content release properties. Therefore, using films with widely diverse surface free energy values, we studied the effects of surface free energy on the content release properties of materials in contact with cans. The results showed that these properties are closely related to the surface free energy of the film material, and that materials with surface free energy of less than 23 mN/m or greater than 44 mN/m show excellent properties for processed meat products with high protein content. The material with PET film coated with mixture of polyester resin and fatty acid is the most promising material for use in food cans in this study. The work has also shown that content release properties can be expressed as a function of adhesion in water between a material and protein. Reducing adhesion can significantly improve content release properties.     

Corrosion in Aluminium Cans with Grape Juice – Influence of Mechanical Damage

The consumption of canned food products from dented cans is not recommended by surveillance and consumer protection agencies due to the possibility of aluminium pick up, which may migrate from package to food/beverage. However, it is necessary to raise scientific data that will support any decision concerning the consumption of this kind of food, especially when the percentage of undernourished persons all over the world is considerable. Drawn and wall ironing–type aluminium cans with 330 ml of ready‐to‐drink grape juice, under three different controlled conditions of can damage as well as without damage, were evaluated for 1 year at 35°C. Aluminium migration, internal pressure and can internal surface appearance were periodically evaluated in order to monitor the package/beverage interaction. The results showed very small variation on the can internal surface appearance and pressure. Even after storage for 365 days, no can presented perforation, although the aluminium migration was increased. The highlight of this work is that after 1 year, for all the evaluated damage conditions, the ready‐to‐drink grape juice in aluminium cans could be considered adequate for human consumption in terms of metal migration from packaging. Copyright © 2013 John Wiley & Sons, Ltd.     

Hot isostatic pressing of metal reinforced metal matrix composites

Metal reinforced Metal Matrix Composites (MMMCs) made by combining an aluminium alloy matrix with stainless steel reinforcing wires are potentially cheaper and tougher than continuous fibre ceramic reinforced Metal Matrix Composites (MMCs). Although they do not give as great enhancements in stiffness and strength, worthwhile gains are achieved. Such MMMCs can be produced by Hot Isostatic Pressing (HIPping), which reduces interfacial reactions in comparison with liquid metal routes. Here, stainless steel (316L) and commercial purity aluminium wires were used to make bundles which were inserted into mild steel cans for HIPping at 525 °C/120 min/100 MPa. Some stainless steel wires were pre-coated with A17Si, to examine the effect of coatings on mechanical properties. Specimens were evaluated in terms of their tensile and fatigue properties. During HIPping, cans collapsed anisotropically to give different cross-section shapes, and for larger diameter cans, there was also some longitudinal twisting. Wires tended to be better aligned after HIPping in the smaller diameter cans, which produced material having higher modulus and UTS. Higher volume fractions of reinforcement tend to give better fatigue properties. Composites with coated stainless steel wires gave higher composite elongation to failure than uncoated wires. Both uncoated and coated wires failed by fatigue during fatigue testing of the composite. This contrasts with ceramic reinforced MMCs where the fibres fracture at weak points and then pull out of the matrix.     

我国气雾罐包装容器标准化研究

目的研究自1991年首次发布气雾罐国标以来我国气雾罐的标准化历程。方法通过解析历次发布的国家标准(GB 13042,GB/T 25164)和包装行业标准(BB/T 0006),从气雾罐形式、分类、规格尺寸、耐压性、检验项目等方面阐述我国气雾罐制造技术标准化的更新改进。结果气雾罐标准化的发展趋势,一方面是气雾罐不断满足气雾剂产业日益多样化的需要,另一方面是保证危险包装产品的质量安全需要,也是适应轻量化、节材化的绿色包装形势的需要。结论在深度参与国际合作与竞争过程中,我国气雾罐制造业国际化程度相当高,标准化工作需进一步与国际接轨,以引领行业发展。     

A notched cross weld tensile testing method for determining true stress-strain curves for weldments

Cross weld tensile testing is widely used in the industry to qualify welds. In these conventional testing fracture load is measured and the location of fracture (weld metal, base metal or heat affected zone) is evaluated. Because the load-elongation curve depends on the location of fracture and the initial gauge length, it cannot be utilized in the failure assessment of weldments. Failure assessment of weldments requires input of true stress-strain behaviour for each material zone. In this paper, a notched cross weld tensile testing method is proposed for determining the true stress-strain curve for each material zone of a weldment. In the proposed method, cylindrical cross weld tensile specimens, with a notch located either in the weld metal, base metal or possibly heat affected zone are applied. Due to the notch, plastic deformation is forced to develop in the notched region. A load versus diameter reduction curve is recorded. It has been shown that the true strain at maximum load is independent of the notch geometry. Furthermore, the materials true stress-strain curve can be determined from the recorded load versus diameter reduction curve of a notched cross weld tensile specimen by dividing a geometry-factor G, which is approximated by a quadratic function of the specimen diameter to notch radius ratio and a linear function of the true strain at the maximum load. It is found that G is independent of the material zone length when the homogenous material length is larger or equal to the minimum diameter.     

Solving an apparel trim placement problem using a maximum cover problem approach

A trim placement problem from the apparel industry is presented and solved. The problem is related to cutting and packing problems, which have received attention in the literature for close to 40 years. The problem is motivated by a pants layout problem involving irregularly-shaped pieces. A two-stage strategy is commonly employed, with large pieces, or panels, arranged first, followed by smaller pieces, or trim. This paper assumes the panels have been arranged, and presents an approach for placing the trim pieces into unused “containers” of the stock material. Groups of trim pieces are first generated using existing polygon containment algorithms. Then, groups are assigned to containers to maximize a weighted function of the trim pieces. The mathematical programming formulation is developed, which is a generalization of the Maximum Cover Problem, a well-known problem in the location literature. Due to wide variability in branch and bound solution times, a Lagrangian Heuristic incorporating an improvement heuristic is developed. Computational experience demonstrates the effectiveness of the Lagrangian Heuristic on real pants markers. The optimal solution is found for all, and solution times are less than branch and bound in 10 out of 12 problem instances (considerably less in three), and only slightly more in the other two. Times are also less variable than branch and bound, an important characteristic with an interactive layout system.     

Dielectric constant measurement of low loss liquids using stacked multi ring resonator

The concept of dielectric constant measurement has been extended and applied in agriculture, pharmaceutical and food industry for quality control of liquids. Dielectric analysis of material at microwave frequencies can be done using novel shielded stacked multi-ring resonator (SMRR). The dielectric constant of liquids and paste has been calculated using SMRR with greater accuracy than the planar resonator, boxed resonator and stacked resonator. SMRR contains a ring resonator with fed patch and parasitic patch with different numbers and sizes of rings. The dimensions of rings on the parasitic patch are optimized to achieve Quality factor Q greater than 100 and return loss less than ?2 dB. Due to dual resonance in novel SMRR, structure losses are reduced by 50% than planar resonator structure. The behavior of SMRR structure at the 2.45 GHz frequency is studied with E field and H field. 3D model is designed in Computer Simulation Technology Microwave Studio (CST MWS) using TLM (Transmission Line Modeling) solver. Electromagnetic field analysis as well as impedance bandwidth of SMRR using CST MWS 3D model prove that electromagnetic coupling in SMRR structure increases thus improves quality factor. In SMRR quality factor increases and losses reduce help us to predict the complex permittivity of material for quality analysis.     

Failure Analysis of Tuna Cans

A metal container used for food packaging must preserve the food’s edibility characteristics for a long period of time. Lacquered tinplate is suitable for canning food provided that the cans are airtight. This article details a root cause failure analysis that was conducted utilizing a sample of tuna cans taken from an affected batch of one million units. Several examinations were carried out to identify the failure’s root cause: visual examination, SEM fractography, micro-hardness measurement, and microstructural characterization. The cracks are located in the HAZ of the welded zone. As a result of the examinations carried out, the authors were able to identify the cause of the primary failure. The identified fracture mechanism is that of stress corrosion cracking (SCC), due to both the aggressive environment (high water content in the oil) and the low lacquer adhesion caused by superficial welding irregularities.     

Case Study – Analysis of Fractured Bottoms of Paint Cans

The purpose of this study was to determine the root cause of fracture in bottoms of rectangular 18 l cans of water‐based acrylic paint used in the building industry and sold in retail. Following a change in the formulation of the inner coating of the cans, fractures developed in the double seams of the can bottoms, which were made of electrolytic chromium/chromium oxide‐coated steel internally coated with pigmented varnish (epoxy melamine). Slight differences were detected in the infrared spectra of both the new and altered varnishes produced with the same base resin. The microanalysis of paint samples collected from both damaged and undamaged cans revealed presence of practically the same elements. The evaluation of the varnished surface of can bottoms revealed depressions in the varnish of all cracked bottoms, inclusive in the curved areas and bottom hook of the double seam, which did not get in direct contact with the paint. However, depressions were not detected in undamaged can bottoms. The metallographic analysis did not reveal significant differences between the microstructures of the metal of cracked or uncracked bottoms. The conclusion was that paint elements got in contact with the steel sheet in the defective spots of the varnished surface, thus starting punctual corrosion that evolved to stress corrosion with ensuing rupture. The stressing agent was the weight of the paint itself or else residual metal stress due to the change in its microstructure caused by the metal‐forming process. Copyright © 2017 John Wiley & Sons, Ltd.     

Manual metal arc weld modelling: Part 2 Treatment of multipass weld

Abstract

The premature failure of parts designed to operate at high temperatures often occurs in low-ductility microstructures in a weld or its heat-affected zone (HAZ). Clearly, a knowledge of how the welding process variables determine these microstructures is essential to the designer of welding procedures. In an accompanying paper relationships are established which describe how the dimensions of single manual metal arc weld beads and their associated HAZs are related to the welding process parameters. Here it is shown how these relationships can be used to optimize the metallurgical properties of multipass welds by controlling the process parameters. The factors given particular attention are dilution of the weld metal by the parent material, refinement of the HAZ using controlled deposition, and refinement of the structure of the weld metal. Data for BOC Murex Suprex B welding electrodes and a mild steel substrate are used throughout for illustration, but the methods presented are applicable to other combinations of materials provided the correct material constants are used. The present work was prompted by a need to improve metal deposition rates during manual metal arc repair of foundry defects in large Cr–Mo–V castings. The practical implementation of the results is also considered.

MST/193b     

Assessing Acute Toxicity of Selected Packages Internal Layers Extracts using Microtox®

In the scientific literature related to the widely understood issue of packaging materials designed to have contact with food (food contact materials), there is much information on raw materials used for their production, as well as their physiochemical properties, types and parameters. Unfortunately, not much attention is given to the issues concerning migration of toxic substances from packaging and its actual influence on the health of the final consumer, even though health protection and food safety are the priority tasks. The goal of this study was to estimate the impact of particular foodstuff packaging type, food production and storage conditions on the degree of leaching of potentially toxic compounds to foodstuffs with the use of the acute toxicity test Microtox^®. From all simulants studied, the 3% acetic acid in water proved to cause significant migration of toxic compounds with increase of time and temperature of extraction and justified the hypothesis that food products with low pH values (stored in cans) cause significant damage to cans internal resin filing and is a reason of increased migration rate of package material to foodstuff. Copyright © 2017 John Wiley & Sons, Ltd.     

METHODS OF IMPROVING WORK-PLACE LAYOUT

Mass production of man-operated machines entails that their dimensions should be so designed as to suit the majority of their users.

The first part of the paper is devoted to a critical review of work-spaces which demonstrates the discomfort to which certain average individuals are subjected. These individuals are the result of world-wide anthropometric-statistical measurements carried out over a number of years.

Ergonomists have widened the conception of work-spaces by introducing improved trial-and-error methods. They have constructed clearance tables for various body regions, as well as manikins to scale and mock-ups of work-spaces, into which certain average individuals were placed.

It thus seems that a new method has come into use which integrates ergonomic data concerning body dimensions and the optimal angles between the various body segments. One can, therefore, no longer consider the dimensional adaptation of work-spaces as consisting in the mere application of a series of separate recommendations but one must take into account the complex structure of the entire human frame. Furthermore, this method has the advantage of disposing of biological standards which are irrelevant to engineering practice. and it proposes technical recommendations such as are customary in research departments.     

Composite material made of plasmonic nanoshells with quantum dot cores: loss-compensation and ε-near-zero physical properties

A theoretical investigation of loss-compensation capabilities in composite materials made of plasmonic nanoshells is carried out by considering quantum dots (QDs) as the nanoshells' cores. The QD and metal permittivities are modeled according to published experimental data. We determine the modes with real or complex wavenumber able to propagate in a 3D periodic lattice of nanoshells. Mode analysis is also used to assess that only one propagating mode is dominant in the composite material whose optical properties can hence be described via homogenization theory. Therefore, the material effective permittivity is found by comparing different techniques: (i)?the mentioned mode analysis, (ii)?Maxwell Garnett mixing rule and (iii)?the Nicolson-Ross-Weir method based on transmission and reflection when considering a metamaterial of finite thickness. The three methods are in excellent agreement, because the nanoshells considered in this paper are very subwavelength, thus justifying the parameter homogenization. We show that QDs are able to provide loss-compensated ε-near-zero metamaterials and also loss-compensated metamaterials with large negative values of permittivity. Besides compensating for losses, the strong gain via QD can provide optical amplification with particular choices of the nanoshell and lattice dimensions.     

Optimizing the magnetic system parameters inside a measuring coil

Conclusions The magnetic core inside the coil of a magnetic measuring system has an optimal diameter to height ratio d_m/h_m for which the torque is maximal. The magnet diameter and height depend on the coil perimeter P, and their optimal ratio K_F is practically independent of the coil perimeter but depends on the alloy of which the magnet is made. Implementing optimal magnet dimensions makes possible fuller utilization of the energy of a permanent magnetic core inside the magnetic system coil. If the optimal ratio of magnet diameter to its height is known, calculation of the magnetic system parameters and the design of the entire measuring instrument becomes quite simple.Translated from Izmeritel'naya Tekhnika, No. 4, pp. 32–34, April, 1991.     

Low-cost and nanoscale non-volatile memory concept for future silicon chips

Non-volatile 'flash' memories are key components of integrated circuits because they retain their data when power is interrupted. Despite their great commercial success, the semiconductor industry is searching for alternative non-volatile memories with improved performance and better opportunities for scaling down the size of memory cells. Here we demonstrate the feasibility of a new semiconductor memory concept. The individual memory cell is based on a narrow line of phase-change material. By sending low-power current pulses through the line, the phase-change material can be programmed reversibly between two distinguishable resistive states on a timescale of nanoseconds. Reducing the dimensions of the phase-change line to the nanometre scale improves the performance in terms of speed and power consumption. These advantages are achieved by the use of a doped-SbTe phase-change material. The simplicity of the concept promises that integration into a logic complementary metal oxide semiconductor (CMOS) process flow might be possible with only a few additional lithographic steps.     

Potential environmental gains from reducing food losses through development of new packaging – a life‐cycle model

Food losses are seldom included in life cycle analyses of the food packaging system, nor are they included in the debate on sustainable packaging. The development of packaging that decreases food losses does, however, provide an opportunity to reduce the overall environmental impact. In this paper, we present a model that calculates the environmental impact of the food packaging system as a function of food losses. The model can be used to analyse the potential environmental gains from developing packaging that reduce food losses. The model includes food production and processing, transports, packaging, retailer and consumer issues and waste handling. The results show that it can be environmentally motivated to increase the environmental impact of packaging, if necessary, when new packaging design helps to reduce food losses. However, the waste handling systems of food and packaging are important to consider if packaging are developed in order to reduce the environmental impact of the food‐packaging system. Copyright © 2010 John Wiley & Sons, Ltd.     

Low velocity axial impact crushing performance of empty recyclable metal beverage cans

This paper focuses on the axial impact crushing behaviour of recyclable empty metal beverage cans available in the market. The idea is to make a macro foam (sacrificial cladding structure) out of these cans to protect the main load bearing members of civil engineering structures from the air blast load. Axial drop weight tests have been conducted to understand the crushing characteristics and the corresponding energy absorption of a single empty beverage can in detail. To conduct such tests a small-scale drop weight test set-up has been designed and manufactured. The deformation mechanisms and the corresponding energy absorption of the beverage cans were studied in detail for different initial impact velocities (1.4 m/s, 2.2 m/s, 3.1 m/s, 3.8 m/s, 4.4 m/s and 4.9 m/s). Furthermore, an analytical model is proposed to calculate the crushing parameters of empty metal beverage cans. The results from the analytical model are compared and validated with the experimental results.     

Theory of Four-Point Direct-Current Potential Drop Measurements on a Metal Plate

ABSTRACT

Four-point direct-current potential drop techniques are well-suited for accurate, nondestructive measurement of material conductivity (or resistivity). From measurements of potential drop on a large metal plate, the electrical conductivity of the plate can be inferred if the thickness of the plate and the dimensions of the probe are known. In this work, an expression for the voltage measured by a four-point probe in contact with a large metal plate of arbitrary thickness is derived from an analytic series representation of the electric field in the plate. The position of the voltage pickup points is permitted to be offset with respect to the current injection points, allowing analysis of colinear, rectangular, and square-head probes. Analytical asymptotic expressions are derived in the limiting cases of plates that are thin or thick with respect to the dimensions of the probe. The range of plate thicknesses for which the asymptotic expressions are valid is determined as a function of relevant probe dimensions. The results of this study provide a useful guide in selecting the most appropriate arrangement of probe points for measurement of the electrical conductivity of large metal plates, depending on the level of accuracy required. Theory is compared with experimental data for measurements made with colinear probes on a variety of metal plates and very good agreement is obtained.