Package Geometry Research Articles

Improving radio frequency heating uniformity in peanuts: Effects of packaging geometry, electrode gap, particle size and interlayer displacement process

This study aimed to assess the impact of various processing parameters including electrode gap, packaging geometry, and particle size on the heating efficiency of radio frequency (RF) processing for peanut thermal decontamination. In addition, interlayer displacements were presented to evaluate the effect of the mixing on heating uniformity.Experimental studies were carried out using 3D-printed polylactic acid (PLA) containers (square, rectangular, and cylindrical) to place the peanut samples with particle sizes ranging from 0.71 to 2.00 mm at 100–140 mm electrode gaps. Temperature changes within the samples were monitored using fiber optic sensors and surface temperature distributions were determined with an infrared camera. Heating uniformity index (λ) was then calculated to assess the effects of RF processing conditions on RF heating uniformity.Results showed that the cylindrical container exhibited a more consistent and uniform heating profile (λ = 0.12) with 1.58 °C min−1 heating rate compared to other containers, and a single interlayer displacement between top and bottom layers further improved temperature distribution uniformity. Smaller particle sizes also led to faster heating rates from 1.71 to 1.55 °C min−1 with more uniform heating due to the reduced porosity within the particles with increased thermal conduction and electromagnetic energy absorption. This study presented valuable insights for developing an effective RF process as an alternative to conventional thermal treatments for decontamination of low-moisture, high-fat particulate foods. Industrial significanceThis research presented an innovative approach applying RF heating for a possible decontamination process for peanut samples. The research tackled the growing worldwide consumer demand for food products to satisfy food safety regulations while peanuts were selected to demonstrate the process effect due to the recent food safety issues in peanut butter considering that a pre-process for decontamination would lead to a decrease in the resulting safety issues.

Developing radio frequency (RF) heating protocol in packed tofu processing by computer simulation

Packed tofu was produced by reheating the mixture of preheated soymilk and coagulant in a sealed container. This study aimed to replace the conventional heating method with RF heating during the reheating of soymilk for packed tofu production. In this study, dielectric properties (DPs), thermal properties (TPs), and rheological properties of soymilk were determined. A mathematical model was developed to simulate the RF heating process of soymilk to determine the appropriate packaging geometry. Water holding capacity (WHC), texture analysis, color measurement, and microstructure observation were performed to evaluate the quality of RF-heated packed tofu. Results showed that soymilk added with Glucono-Delta-Lactone (GDL) coagulated at the temperature above 60 °C, and the loss factor (ε″) was slightly reduced when soymilk was converted to tofu at coagulation temperature. Based on the simulation results, the cylindrical vessel (φ50 mm × 100 mm) was chosen as the soymilk container for desired heating rate (5.9 °C/min) and uniformity (λ = 0.0065, 0.0069, 0.0016 for top, middle, and bottom layers). The texture analysis revealed that the hardness and chewiness of packed tofu prepared by RF heating were enhanced (maximum 1.36 times and 1.21 times) compared with commercial packed tofu, while the springiness were not significantly changed. Furthermore, the denser network structure was observed inside RF-heated packed tofu by SEM. These results indicated that packed tofu prepared by RF heating was of higher gel strength and sensory quality. RF heating has the potential to be applied in packed tofu production.

DNA Origami Disguises Herpes Simplex Virus 1 Particles and Controls Their Virulence.

DNA nanostructures are well-established vectors for packaging diversified payloads for targeted cellular delivery. Here, DNA origami rectangular sheets were combined with Herpes Simplex Virus 1 (HSV1) capsids to demonstrate surface coverage of the particle via electrostatic interactions. The optimized origami:HSV1 molar ratios led to characteristic packaging geometries ranging from dispersed "HSV1 pockets" to agglomerated "HSV1 sleeves". "Pockets" were disguised from cells in HeLa and B16F10 cells and were 44.2% less infective than naked HSV1 particles. However, the pockets were 117% more infective than naked HSV1 particles when the origami sheets were coated with folic acid. We observed infectivity from naked origami, but they are 99.1% less infective with respect to HSV1 and 99.6% less infective with respect to the pocket complexes. This work suggests that DNA origami can selectively modulate virus infectivity.

Development of 3-D Wafer Level Packaging for SAW Filters Using Thin Glass Capping Technology

The introduction of 5G mobile communication created the need to support a large number of radio frequency (RF) bands. This required high performance and reduced size for microacoustic filters. Based on these requirements, a new three-dimensional wafer-level packaging (3-D WLP) solution based on the predecessors’ developed technology was presented to resolve reliability issues for surface acoustic wave (SAW) filter packages with large cavities. In the 3-D WLP, vertical interconnects were realized using through glass vias (TGVs). To enable such a process scheme, thin glass caps with TGVs were formed through laser-induced chemical etching. Then, glass capping dies were bonded on the corresponding LiTaO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> (LT) device wafer to generate a cavity structure. Partial filling of the vias on the pad was used, and a metal trace was formed on the glass. Ball grid arrays (BGAs) were formed on top of the glass. Finally, an SAW filter WLP was fabricated. This glass capping packaging avoids the outgassing problem of conventional thin-film acoustic packaging at high temperatures, which would cause the contamination of the interdigital transducers (IDTs). In addition, a numerical study based on the 3-D finite element (FE) model has been conducted to analyze the reliability of the package. The built model was applied to perform parametric studies on the effects of package geometry, material properties, and the processing conditions on reliability. Based on the above studies, the optimized SAW filter WLP successfully passed the reliability test of pre-con level 3 and temperature cycling test (TCT, −40 °C ~ 125 °C).

Renewable, Sustainable and Natural Materials on Food Packaging: Primary Data for Robotically Detect Packaging Shape in Logistics

In the past decades, plastic packaging was a key material to preserve, protect, store, and transport food products. It was shown in food logistics from the manufacturers to consumers. The cost of making plastics is cheap. It was determined by the energy input that used to process them. Ingredients used to create plastics are very inexpensive. Furthermore, food packaging is a container. If it made from plastic material, it was also durable and last long over the shelf life of foods. Due to the sustainability concerns, using plastic packaging will cause the environment issues. Recovering the environment will help the earth to remain supporting life. This research aims to summarise the findings of smart packaging using different types of materials consisted of renewable, sustainable, and natural materials. A state-of-the-art food packaging geometry is explained. The data trends of intelligent food packaging were found to associate with sustainable development goals

Assessment of insulating package performance by mathematical modelling

A mathematical model has been developed in the present work to describe the temperature change in a typical insulated shipping container as a function of time. The model was created by combining steady state and transient models in a 2D geometry of a typical shipping container and was subsequently validated by an ice melt test and comparison of temperature change obtained from the model and experimental measurement. An excellent agreement was obtained between the computational model developed in this work and experimental results. In addition, a parametric study was also carried out to investigate various factors in controlling the insulation performance of the packaging. It was found that the model has capability of evaluating the effect of a wide range of packaging design parameters such as thermal conductivity, surface emissivity, packaging geometry, and sounding temperature.

Development of a package-sterilization process for aseptic filling machines: A numerical approach and validation for surface treatment with hydrogen peroxide

Within the present work a sterilization process by a heated gas mixture that contains hydrogen peroxide (H2O2) is validated by experiments and numerical modeling techniques. The operational parameters that affect the sterilization efficacy are described alongside the two modes of sterilization: gaseous and condensed H2O2. Measurements with a previously developed H2O2 gas sensor are carried out to validate the applied H2O2 gas concentration during sterilization. We performed microbiological tests at different H2O2 gas concentrations by applying an end-point method to carrier strips, which contain different inoculation loads of Geobacillus stearothermophilus spores. The analysis of the sterilization process of a pharmaceutical glass vial is performed by numerical modeling. The numerical model combines heat- and advection-diffusion mass transfer with vapor–pressure equations to predict the location of condensate formation and the concentration of H2O2 at the packaging surfaces by changing the gas temperature. For a sterilization process of 0.7 s, a H2O2 gas concentration above 4% v/v is required to reach a log-count reduction above six. The numerical results showed the location of H2O2 condensate formation, which decreases with increasing sterilant-gas temperature. The model can be transferred to different gas nozzle- and packaging geometries to assure the absence of H2O2 residues.

Encapsulation of Fiber Optic Sensors in 3D Printed Packages for Use in Civil Engineering Applications: A Preliminary Study.

Fiber optic sensors have considerable potential for measuring strains in the challenging environment posed by today’s civil engineering applications. Their long-term reliability and stability are particularly important attributes for assessing, with confidence, effects such as cracking and response to normal (and abnormal) loads. However, given the fragile nature of the bare fiber, the sensors must be packaged to achieve adequate robustness but the resulting increased cost of installation can frequently limit the number of sensors which can be installed or their use may have to be ruled out altogether due to these financial constraints. There is thus potential for the development of a more affordable type of packaging and this paper describes work undertaken to produce a cost-effective and easy-to-use technique for encapsulating fiber optic sensors in resin, taking advantage of 3D printing techniques which are widely available and at low cost. This approach can be used to produce a robust, inexpensive packaged sensor system which is seen as being suitable to be extended to a wider range of uses including installation in concrete structures prior to casting. To evaluate this approach, several such 3D printed package types and geometries are described and their behavior is assessed from a programme of laboratory trials, the results of which are presented in this paper. This proof-of-concept testing has demonstrated the considerable potential which 3D printed packages have and the scope for further development and consequent use in civil engineering applications. Areas showing promise and potential, which have been identified from the work undertaken, are discussed.

Topology: A Source of Nonlinearity in the MEMS Thermal Accelerometer

This article reports the effect of package and constituent geometries on the response linearity of a micromachined single-axis thermal accelerometer. To investigate this phenomenon, a packaged device is filled with a high-density gas inside a sealed chamber on a rotation stage, and its response is measured as its sensitive axis of acceleration is tilted relative to the Earth's gravitational acceleration g 9.81ms2 . Linearity of the response is examined compared to an analytical model describing natural convection between horizontal heated concentric cylinders. In a 360 turn, full-scale nonlinearities of 3.1 and 0.9 are measured in each half cycle. This asymmetrical performance is attributed to a lower level of geometrical symmetry in the packaged device. To compensate for the modulated response, a geometrical correction factor is introduced to the model, improving its performance prediction with a symmetrical full-scale linearity error of 0.5.

Warpage simulation and experimental verification for 320 mm × 320 mm panel level fan-out packaging based on die-first process

Warpage for 320 mm × 320 mm panel level fan-out packaging based on die-first process was investigated by both simulation and experimental approaches. In the present paper, a simple and efficient FEA (Finite Element Analysis) method based on shell element was introduced. Finite element models were built by using the software of Ansys products to predict and analysis the warpage for feasibility of large panel fan-out packaging technology in aspect of material, package geometries, package size, process conditions and metal density. In order to verify the accuracy and the precision of the simulation method, test vehicle with dies was fabricated by using low cost ‘die first (face down)’ fan-out technology. Warpage of the test vehicle was measured by using Shadow Moiré method. The simulated warpage result and the experimental one exhibit good consistency.

Reliability assessment of electronic assemblies under vibration by statistical factorial analysis approach

PurposeThis paper aims to present a reliability performance assessment of electronic packages subjected to harmonic vibration loadings by using a statistical factorial analysis technique. The effects of various geometric parameters, the size and thickness of the printed circuit board and component and solder interconnect dimensions on the fundamental resonant frequency of the assembly and the axial strain of the most critical solder joint were thoroughly investigated.Design/methodology/approachA previously published analytical solution for the problem of electronic assembly vibration was adopted. This solution was modified and used to generate the natural frequency and solder axial strains data for various package geometries. Statistical factorial analysis was used to analyze these data.FindingsThe results of the present study showed that the reliability of electronic packages under vibration could be significantly enhanced by selecting larger and thicker printed circuit boards and thinner and smaller electrical components. Additionally, taller and thinner solders might also produce better reliability behavior.Originality/valueThe results of this investigation can be very useful in the design process of electronic products in mechanical vibration environments.

Investigation of Package Effects on the Edge Termination E-Field for HV WBG Power Semiconductors

Abstract The edge termination of a power semiconductor is defined as the spatial junction terminations around the edges of the power devices. Guard rings are used to contour the internal depletion regions and E-fields as they terminate at the edge termination, i.e. the intersection of the depletion regions and the wafer saw line where the crystal damage is located. Since there is no specific package for WBG power devices, wire bonds are still widely used to interconnect to the topside metal pads of the power devices. From previous research it is shown that wire bonding will not affect the E-field around the guard rings on a WBG device. However, planar power package, such as double-sided and power flip-chip device packaging could be a problem where the close distance between the topside of the power device and conducting plane may negatively affect the E-field distribution of the guard rings, which in turn lowers the reverse blocking capability of the WBG power device and increases leakage current creating greater on-state power loss, or even early break down. Few works have shown the Electric field distribution in embedded power modules. Therefore, a more detailed investigation and possible solution is needed for the proliferation of double-sided power packages. To investigate this packaging problem simulations were performed in Sentaurus TCAD and COMSOL based on the device physics and package geometries. Guard ring structures in 1.2kV and 10kV SiC Schottky Barrier Diode (SBD) were built and simulated in various double-sided package geometries, together with the thermal and mechanical evaluation of the package, to observe the influence on the E-field distribution in and out the WBG device. Different double-sided package structures were evaluated and a guideline (spacing/pad size/etc.) summarized for double-sided design. Moreover, a new bevel edge termination method was evaluated for double-sided WBG power semiconductor devices. Experimental reverse blocking test results will be reported in various temperature (from 25°C to 175°C) to verify the function of the package. The tests are on 1200V/50A SiC SBD (Schottky Barrier Diode) from Global Power Technology, which has double-sided Ag on both sides.

Simulation of packaging under harsh environment conditions (temperature, pressure, corrosion and radiation)

An important role of microelectronic packages is the protection of the chip against environmental influences like moisture, pollutants and other chemical active species. If the chip is exposed to these conditions, for instance corrosion is resulting. Furthermore, due to high temperature load and pressure or vibrations, the reliability of the package is influenced by thermo-mechanical stress. The unavoidable presence of particle radiation on ground and in the atmosphere leads to unwanted failures in the electronic devices, partly affected by the package material and solder. All these harsh conditions will happen more and more in the frame of automotive, medical and avionic applications. For space application all of these parameters are important as well.Due to this, an essential aspect of the package design is the careful combination of materials to avoid mechanical stress and to improve the thermal-electrical and mechanical behavior as well as the corrosion resistance and radiation hardness of the package.Simulation analysis can give, using the appropriate software, depending on the material properties, the package geometry as well as the boundaries, a fast and reliable solution to investigate the influence of mechanical stress as well as the thermal, electrical and mechanical behavior of the package.

Thermal conductivity measurements of impregnated Nb3Sn coil samples in the temperature range of 3.5 K to 100 K

In the framework of the luminosity upgrade of the LHC, high-field magnets are under development. Magnetic flux densities of up to 13 T require the use of Nb3Sn superconducting coils. Quench protection becomes challenging due to the high stored energy density and the low stabilizer fraction. The thermal conductivity and diffusivity of the combination of insulating layers and Nb3Sn based cables are an important thermodynamic input parameter for quench protection systems and superfluid helium cooling studies. A two-stage cryocooler based test stand is used to measure the thermal conductance of the coil sample in two different heat flow directions with respect to the coil package geometry. Variable base temperatures of the experimental platform at the cryocooler allow for a steady-state heat flux method up to 100 K. The heat is applied at wedges style copper interfaces of the Rutherford cables. The respective temperature difference represents the absolute value of thermal conductance of the sample arrangement. We report about the measurement methodology applied to this kind of non-uniform sample composition and the evaluation of the used resin composite materials.

Simplified Mathematical Model of a novel ‘Closed Loop Two-Phase Wicked Thermosyphon (CLTPWT)’

A novel “Closed Loop Two-Phase Wicked Thermosyphon (CLTPWT)” was designed, fabricated, and tested by a California-based start-up company for thermal management of overhead light emitting diodes (LEDs). This device is comprised of a central evaporator and a circular heat exchanger coil connected by transport lines. Despite the presence of a porous wick structure in the evaporator, gravity provides the necessary driving potential for circulation of the working fluid in this device and therefore the name CLTPWT. A thermal model of this device was previously developed (by the authors) to predict its thermal performance. The evaporator model employed in the previous study assumed constant thermal resistances that were obtained from one specific ‘size’ of the evaporator. This paper simplifies this existing model by mathematically decoupling the evaporator from the coil of the device. The primary objective of the model is to obtain temperature predictions that are not based on an evaporator package geometry (size) which permits investigation of a wider operating power range. In addition, this model accounts for the mass flow rate of the working fluid based on a steady state pressure balance, as opposed to the previous model which estimates this based on the thermal solution. The model predicts thermal performance of the device in terms of the evaporator (and condenser) saturation temperature (Tsat), sub-cooler temperature (Tsc), and two-phase mixture quality (x evp) leaving the evaporator package. These predictions are compared with both experiments performed in a limited operating power range and with the predictions based on the previous model. The predictions of the current model are found to be in good agreement with both. In addition, this paper also reports the effect of independent variables such as the air temperature (Tair) and fill volume (V fill) on the performance of the CLTPWT.

Heat transfer finite element model of fresh fruit salad insulating packages in non-refrigerated conditions

The quality of many foods is significantly affected by temperature fluctuations that can occur during distribution and transport. Packaging materials can help to shield the product from temperature variation by increasing the heat transfer resistance. Thermal insulation power is influenced by several factors, such as material, geometry, and degree of contact between materials. To maintain the cool chain of fruit salad with syrup during the transportation (temperature less than 5 °C), thermal insulation effect of different packaging materials was investigated. A parametric analysis using a finite element model able to describe the heat transfer inside the containers, on varying packaging material (expanded polystyrene: EPS, and air), geometry, dimension, and boundary conditions, was developed and validated. Good agreement was obtained between numerical and experimental results (R2 up to 0.98). The effectiveness of the insulation configurations was evaluated by determining the time taken for the temperature to rise the critical value of 5 °C. Results showed that insulating performance of the air is better than EPS. This is realistic only taking into account insulation layer less than 0.013 m. From a practical point of view, an EPS packaging could result stronger compared to a packaging characterised by an insulating air layer. For the same EPS insulation thickness, product temperature exponentially decreases with the volumetric capacity (R2 = 0.99).

Effects of Packaging Geometry on Heat Penetration Time in Retortable Semi-Rigid Plastic Trays

Semi-rigid, retortable trays were filled with a food simulate and thermally processed in a water immersion automated batch retort system at rotational speeds of 6 RPM and 11 RPM. Triangle, rectangle, oval, and round trays were evaluated, each having approximately the same overflow capacity. During processing, trays were fixed in place with racks containing one shape per rack. Various rack location combinations were tested to provide processing data for each shape in each rack location. Heat penetration data was gathered using thermocouples located in the geometric center of each tray shape and this data was modeled to determine the slowest heating container. No differences were observed in rack location among tray geometries at either RPM level (P>0.05). The data generated during heat penetration runs was also used to model different retort temperatures and lethality values. A retort temperature of 215°F and a lethality value of 10 showed the highest average sterilization time (P 0.05) than any other shape tray. At a rotational speed of 11 RPM, differences in average process time to reach lethality between tray geometries were insignificant (P>0.05).

Effects of Packaging Geometry on Heat Penetration Time in Retortable Semi-Rigid Plastic Trays

Effects of Packaging Geometry on Heat Penetration Time in Retortable Semi-Rigid Plastic Trays

Computer simulation analyses to improve radio frequency (RF) heating uniformity in dried fruits for insect control

Abstract In recent years, radio frequency (RF) heating has been explored as a new postharvest pest and pathogen control procedure for agricultural commodities and dry food ingredients. Non-uniform heating and, sometimes runaway heating, have been the major challenges with implementation of this technology. In this study, an experimentally validated computer simulation model was developed to predict the effects of different package geometries, electrode configurations, and use of forced air (60 °C) on improving the heating uniformity of raisins treated with RF for insect control. Higher temperatures (60–76 °C) were observed in the areas between the edges and corners on the top and bottom layers of the RF treated raisins held in rectangular and cylinder shaped containers, with lower temperatures (40–52 °C) observed in the central areas of each layer. The heating uniformity was improved by rounding the corners of the containers and reducing sharp edges on the packages, modifying electrode configurations, and applying forced air after RF heating. These modifications reduced the maximum temperature difference throughout a container of heated raisins to about 5 °C. Approximately 356 min were needed to raise the raisin temperature in a rectangular container from 23 °C to 55–60 °C using only forced air at 60 °C. In contrast, only 6 min of RF heating followed by 10 min of forced air treatment at 60 °C was needed for a similar filled container to reach a temperature of 55–60 °C. Shortening the electrodes length to 4 cm shorter than the horizontal dimensions of the rectangular containers also improved heating uniformity. This technique can be easily implemented to improve the uniformity of RF heating in the food industry for the control of insects in packaged dried fruits. Industrial relevance The results in this study provide essential information about the non-uniform heating inside the RF heated materials packed in containers with sharp areas, edges and corners, such as rectangular and cylindrical shaped containers. Rounding the edges and corners in the containers or bending the top and bottom electrodes is key parameters to control the electrical field inside the RF system. This technique can be easily implemented to improve the uniformity of RF heating in the food industry for the control of insects in packaged dried fruits.

Genome-Wide Mapping of Chromatin Secondary Structure using Ionizing Radiation Coupled with Sequencing

Chromatin packages two meters of human DNA into a five-micron nucleus while allowing regulated access to the genome. At the intermediate length scale of ∼1 kilobase, which spans nucleosome-nucleosome interactions, chromatin structure is expected to play a crucial role in regulating transcription, DNA replication and DNA repair. However, our structural understanding of this level of chromatin organization continues to lag behind our rapidly developing understanding of both single nucleosomes and higher-order, long-range interactions. We have developed a novel method, RICC-seq, for probing chromatin structure at this poorly understood length scale. RICC-seq uses hydroxyl radicals generated by ionizing radiation to create sparse and spatially correlated strand breaks that result in short DNA fragments. The lengths and mapping locations of these fragments can be used to place basepair-resolved pairwise distance constraints on sequence loci in 3D space. In order to understand the detailed architecture underlying chromatin compaction and DNA accessibility, we have generated the first genome-wide RICC-seq maps of chromatin compaction in terminally differentiated fibroblasts, comparing chromatin structure between heterochromatic and euchromatic regions. These data reveal differential packaging geometries for heterochromatic regions with significantly more DNA contacts with specific chromatin post translational modifications. We envision that RICC-seq is a generalizable method for high-resolution understanding of condensed nucleic acids with potential applications to targets as diverse as folded RNA to viral genomes within capsids.