Dry Ice Pellets Research Articles

A non-invasive capacitive sensor to investigate the Leidenfrost phenomenon: a proof of concept study

A volatile sessile liquid droplet or a sublimating solid manifests levitation on its own vapor when placed on a sufficiently heated surface, illustrating the Leidenfrost phenomenon. In this study, we introduce a non-invasive capacitance method for investigating this phenomenon, offering a potentially simpler alternative to existing optical techniques. The designed sensor features in-plane miniaturized electrodes forming a double-comb structure, also known as an interdigitated capacitor. Initially, the sensor’s capacitance is characterized for various distances between the sensor and a dielectric material. The influence of the sensor substrate material and the spacing between the electrodes on the sensor’s capacitance is also investigated. To demonstrate the feasibility of the method, a sublimating dry ice pellet is placed on the capacitive sensor, and its performance is evaluated. We present results for the dimensionless vapor layer thickness and the pellet’s lifetime at different substrate temperatures, derived from the capacitance output. The results are compared with Optical Coherence Tomography (OCT) data, serving as a benchmark. While the temporal evolution of the sensor’s output, variation in the dimensionless vapor layer thickness, and the lifetime of the dry ice pellet align with expected results from OCT, notable quantitative deviations are observed. These deviations are attributed to practical experimental limitations rather than shortcoming in the sensor’s working principle. Although this necessitates further investigation, the methodology presented in this paper can potentially serve as an alternative for the detection and measurement of Leidenfrost vapor layers.

Field Comparison of Carbon Dioxide Source with Biogents Sentinel-2 and Pro Traps for Adult Aedes Mosquito Surveillance.

The BG Sentinel-2 (BGS-2) and BG-Pro traps (BGS-2 configuration) were compared for their effectiveness to collect Aedes vectors and related nuisance mosquitoes in north central Florida during 2022. Traps were baited with either dry ice pellets, pressurized carbon dioxide (CO2) gas, or the novel BG yeast-derived CO2 generator. Additionally, each trap was fitted with the BG Sweetscent lure. Sixteen species were collected including Aedes albopictus and Ae. aegypti, which accounted for about 20% of the collections. The BGS-2 collected more mosquitoes compared to the BG-Pro, but the relative percent abundance of each species to total collection from each trap type was similar. Overall mosquito abundance was significantly greater in both trap types baited with dry ice compared with the other CO2 sources. Significantly more Ae. albopictus were collected from BGS-2 traps baited with dry ice than all other CO2 and trap configurations. Lastly, we did not observe any significant differences in Ae. aegypti abundance between trap type or CO2 source.

Influence of Die Land Length on the Maximum Extrusion Force and Dry Ice Pellets Density in Ram Extrusion Process.

The management of waste materials, particularly non-biodegradable substances such as plastics and composites, is an increasingly pressing issue. Energy efficiency in industrial processes is crucial throughout their life cycle, including the handling of materials such as carbon dioxide (CO2), which has a significant environmental impact. This study focuses on the conversion of solid CO2 into pellets using ram extrusion, a widely used technique. The length of the die land (DL) in this process plays a critical role in determining the maximum extrusion force and the density of dry ice pellets. However, the influence of DL length on the characteristics of dry ice snow, known as compressed carbon dioxide (CCD), remains understudied. To address this research gap, the authors conducted experimental trials using a customized ram extrusion setup, varying the DL length while keeping the other parameters constant. The results demonstrate a substantial correlation between DL length and both the maximum extrusion force and dry ice pellets density. Increasing the DL length leads to a decreased extrusion force and optimized pellet density. These findings provide valuable insights for optimizing the ram extrusion process of dry ice pellets and improving waste management, energy efficiency, and product quality in industries utilizing this technique.

Keep cool! Observed temperature variations at different process stages of the biobanking workflow – examples from the Leipzig medical biobank

Abstract Objectives Biobanked samples are becoming increasingly important for research outcomes. Most of the biobanking processes (from preparation to storage) are affected by temperature in a time-dependent manner and have a high impact on sample quality. We aimed to validate time and temperature sensitive processes such as sample preparation, transport, sorting, and storage, which have a high impact on sample quality. Methods Temperature was measured using internal or external temperature data loggers. We analysed the temperature and present real data from our sample transport on dry ice and with the CryoPod, from our ultra-low temperature freezers (UTFs) of different manufacturers and cryostores. We also tested sample sorting on dry ice and in a cryogenic workbench. Results In the UTFs, we identified temperature zones with a temperature difference from 4.7 °C up to 20.8 °C across the whole UTF. For sample transport within approximately 30 min we observed temperatures of −80.2 °C ± 4.0 °C and −173.9 °C ± 16.9 °C for dry ice boxes and the CryoPod, respectively. Sorting on dry ice was best in a polystyrene box half-filled with dry ice pellets, although the temperature increased by 7.5 °C within the first 5 min, whereas the temperature in the cryogenic workbench remained stable below −100 °C for hours. Conclusions Time and temperature play a crucial role in the entire biobanking process, with sometimes immense temperature fluctuations in some equipment. We recommend the validation or verification of all equipment and processes used to avoid pre-analytical errors in accordance with DIN EN ISO 20387.

23255 Devices Engineered to Collect Exhaled Breath Condensate (EBC) and their Applications

ABSTRACT IMPACT: Human exhaled breath is rich in metabolomic content that represents pulmonary function and gas exchange with blood, which can provide insights into an individual’s state of health. OBJECTIVES/GOALS: Human exhaled breath is rich in metabolomic content that represents pulmonary function and gas exchange with blood. It contains a mixture of compounds that offer insight into an individual’s state of health. Here, we present two novel non-invasive breath sampling devices for use in basic medical practice. METHODS/STUDY POPULATION: The two breath samplers have a disposable mouthpiece, a set of inhale and exhale one-way flap valves to allow condensation of exhaled breath only, and a saliva filter. The housing is constructed out of Teflon®, a chemically inert material to reduce chemical absorbance. The first device condenses exhaled breath into a frozen condensate using dry ice pellets and the other is a miniaturized design that liquifies exhaled breath on a condenser surface with micropatterned features on a cooling plate. Both designs have individual strategic and analytical advantages: frozen exhaled breath condensate (EBC) has high retention of analytes and sample volume; EBC collected in liquid phase offers facilitated sample collection and device portability. RESULTS/ANTICIPATED RESULTS: We investigated if breath aerosol size distribution affects the types or abundances of metabolites. We modified the geometry of the first device to redirect aerosol trajectories based on size. The trapping of larger aerosols increases with filter length, thus altering the aerosol size distribution although no significant changes in the metabolite profiles were found. With the miniaturized device, metabolite abundances were measured in a small cohort of healthy control and mild asthmatic subjects. Differences among subjects were found, as well as main differences between control and asthmatic groups. All analyses of EBC were performed with liquid chromatography - mass spectrometry. Inflammatory suppression found in asthmatic subjects can be explained by prescribed daily use of inhaled corticosteroids. DISCUSSION/SIGNIFICANCE OF FINDINGS: Breath collection devices can be used in intensive care units, outpatient clinics, workplaces, and at home. EBC analysis has been used to monitor asthma and chronic obstructive pulmonary disease. It can be applied to infectious respiratory diseases (e.g. influenza, COVID-19) and for monitoring environmental and occupational chemical exposures.

Experimental and numerical study of insulation packages containing dry ice pellets

Shippers of healthcare and food products, in most cases, have regulatory responsibility to ensure quality by maintaining product’s temperature during transportation. Dry ice is commonly used as cold source inside the insulated cold-storage packages which are often transported via air freights. But dry ice sublimation can lead to asphyxiation of crew members or passengers due to which, several regulatory bodies have recommended safe limits of dry ice aboard aircraft mainly based on rule-of-thumb. Prior to establishing the limits, understanding dry ice sublimation is of paramount importance. Therefore the current research, experimentally and numerically explores dry ice sublimation packed in commonly encountered containers made of polystyrene foam. A three dimensional quasi-steady model is developed to predict variation of dry ice mass inside the insulation packages. The model is validated against mass and temperature measurements performed on two types of insulation packages made of different material and geometry. The model is able to fairly predict the reduction in dry ice mass over time and the end-of-sublimation time. Both experimental and numerical results show that the sublimation rate of dry ice can be reduced by covering the inner walls of insulation package with a reflective layer like aluminized mylar foil. The good agreement between model and experimental data of dry ice mass variation makes it possible for the shippers to use the modeling approach in estimating sublimation rates of dry ice.

Optimizing nozzle convergent angle using central composite design on the particle velocity and acoustic power level for single-hose dry ice blasting nozzle

One of the important parameters in developing dry ice blasting nozzle is the high-speed dry ice pellets. However, many studies focus primarily only on its performance without considering the noise emission that comes from an operating nozzle. In this method, the central composite optimization tool has been used. The two-way mass momentum and energy exchange are successfully modeled using the two-way mass momentum model. As an attempt to theoretically verify the model accuracy, a comparison is conducted on the density, pressure, temperature, as well as Mach number ratios corresponding to various ratios of nozzle area. In return, the smallest value of the convergent angle results in the highest velocity of 516.75 m s−1, as well as the highest level of the acoustic power level of 144.36 dB. Besides, one of the vital influencing factors on the emitted acoustic power level is the turbulence intensity, which can achieve a maximum of 1% intensity for an angle of 20° at the throat section. Besides, the same negative sensitivity of around − 0.99% is provided by the velocity and acoustic power level, which is highly responsive toward the convergent angle variation. Furthermore, the optimum nozzle convergent angle for the minimization of the acoustic power level and maximization of the velocity is 7.03°. The novelty of this research lies in the findings on the effective convergent angle of the dry ice blasting nozzle that accelerates the particle flow and minimizes the noise emission from the operating nozzle.

Preliminary analysis of the sensitivity of the algebraic dry ice agglomeration model using multi-channel dies to change their geometrical parameters

The article presents the results of a preliminary analysis of the algebraic sensitivity of the model describing the change in the limit values of densification stress in the process of dry ice agglomeration using multi-channel dies in the piston technique. In the available literature, it was noted that the limit value of compaction stresses significantly exceeds the effective value. This justifies the sense of undertaking work on the development of a multi-channel die that allows the reduction of the value of the indicated stress, which will reduce the consumption of electricity necessary for the production of dry ice pellets. The sensitivity analysis performed is related to the attempt to determine the significance of the impact of individual geometric parameters of the multi-channel die on the value of the limit stress. The results will significantly contribute to the development of a work program related to the optimization of geometrical parameters of the tools used to implement the indicated process.

Influence of divergent length on the gas-particle flow in dual hose dry ice blasting nozzle geometry

A numerical simulation study was performed to examine the effect of nozzle geometry and divergent length on gas-particle flows in dual hose dry ice blasting. The simultaneous model of mass momentum and energy exchange between two phases was solved iteratively. The phases are solid dry ice particle and compressible air fluid as a working medium. The results were presented in the gas flow field along the nozzle centerline. The results showed that increasing divergent length decreases the gas-particle density along the centerline; and the density development along the nozzle centerline decreased along the length. Eddy viscosity of the nozzle cavity was steady for length of 0.25 m, but increased drastically for higher values. The substantial increase in eddy viscosity after that position is due to the mixing flow between dry ice pellet and compressed gas which is diverging out from the nozzle outlet area. Thus, the mixing flow experienced back pressure from the atmospheric pressure. The particle mass concentration decreased by increasing nozzle centerline coordinates. The pressure increased along the length; however, it dropped at the end due to the reverse pressure. The temperature increased steadily because of conversion of turbulence to internal thermal energy. The characteristics of gas-particle flow in the nozzle cavity provide better understanding of multiphase flow in turbine and jet engine flow analysis.

Ultra Cryo-Milling with Liquid Nitrogen and Dry Ice Beads: Characterization of Dry Ice as Milling Beads for Application to Various Drug Compounds.

Ultra cryo-milling using liquid nitrogen (LN2) and dry ice beads has been proposed as a contamination-free milling technique. The morphological change of dry ice beads was visually monitored in LN2 to clarify their production process and cryo-milling process. We found that dry ice pellets, which are starting material of beads and available on the market, immediately disintegrate in LN2, resulting in the spontaneous production of dry ice beads. In addition, the resultant beads maintain their size and shape even under vigorous agitation in LN2, demonstrating that they could play a role of milling media in the milling process. The driving conditions of this cryogenic milling process including beads size were optimized to enhance the milling efficiency. Dry ice beads provided superior milling efficiency compared to original pellets. The milling efficiency increased as the size of the dry ice beads decreased; furthermore, the larger the amount of beads used, the finer the milled particles. Any crystals of three drug compounds were effectively pulverized to the sub- or single-micron range. Cryo-milling with dry ice beads is valuable on pharmaceutical field because it does not contaminate the product with fractured and/or eroded beads.

Numerical Simulations of Glaciogenic Cloud Seeding with Dry Ice Pellets and Liquid Carbon Dioxide under Simplified Conditions

Numerical Simulations of Glaciogenic Cloud Seeding with Dry Ice Pellets and Liquid Carbon Dioxide under Simplified Conditions

Influence of the Value of Limit Densification Stress on the Quality of the Pellets During the Agglomeration Process of CO2

The article presents the results of static compression tests of concentrated crystallized carbon dioxide. Included results of test describe relation between the agglomerating stress and density of compressed dry ice. Quality of dry ice pellet is determined by value of density. Results of research allow to determine the effective value of stress during the agglomeration process. Due to the fact that the crystallized carbon dioxide has temperature equal minus 78.5°C and sublimates under normal conditions of the test was proposed the methodology which allowing performance the tests. In first stage of research has been determined value of bulk density of dry ice snow. This value is initial boundary condition of relation between compression stress and density of agglomerated material. In second stage of the research has been investigated influence of compression stress on to density variation of the agglomerated dry ice. Results of both stage of research allow for formulation of function which approximate relation between density of agglomerated dry ice and compression stress. Results will allow for formulation of assumptions, which will be one of main point to create a more efficient machine for agglomeration process of solidified carbon dioxide.

THE PROSPECTS FOR IMPLEMENTATION OF THE CRYOGENIC BLASTING IN REPAIR OF RAILWAY ROLLING STOCK

The article analyzes the existing methods and techniques of cleaning parts and mechanisms that arecurrently used in railway transport. It’s proposed the implementation of a new modern resource-savingtechnology in cleaning of units and parts of locomotives by means of dry ice pellets, which can be used in arailway rolling stockdepot.The operation principles and benefits of cryogenic blasting are described.

Foam extrusion of LDPE with solid phase CO2 as blowing agent

Physical foaming usually requires special metering equipment to inject the blowing agent at high pressures. In this study, low density polyethylene (LDPE) was foamed in the extrusion process using dry ice as physical blowing agent. The blowing agent was metered in form of pellets over the hopper. To determine relevant process parameters and improve the understanding of the process a melting model is applied. The influence of the formation of a melt film and melt pool on the dissolution of the blowing agent is discussed. The theoretical considerations are validated in a design of experiment study. As a result, the efficiency of the process is especially affected by the throughput rate, granules temperature, and blowing agent concentration. Further varied parameters are the barrel temperature in the melting zone and diameter of the dry ice pellets. Fast melting and pressure build‐up were shown to reduce blowing agent losses. POLYM. ENG. SCI., 55:2821–2828, 2015. © 2015 Society of Plastics Engineers

A simple and inexpensive method for determining cold sensitivity and adaptation in mice.

Cold hypersensitivity is a serious clinical problem, affecting a broad subset of patients and causing significant decreases in quality of life. The cold plantar assay allows the objective and inexpensive assessment of cold sensitivity in mice, and can quantify both analgesia and hypersensitivity. Mice are acclimated on a glass plate, and a compressed dry ice pellet is held against the glass surface underneath the hindpaw. The latency to withdrawal from the cooling glass is used as a measure of cold sensitivity. Cold sensation is also important for survival in regions with seasonal temperature shifts, and in order to maintain sensitivity animals must be able to adjust their thermal response thresholds to match the ambient temperature. The Cold Plantar Assay (CPA) also allows the study of adaptation to changes in ambient temperature by testing the cold sensitivity of mice at temperatures ranging from 30 °C to 5 °C. Mice are acclimated as described above, but the glass plate is cooled to the desired starting temperature using aluminum boxes (or aluminum foil packets) filled with hot water, wet ice, or dry ice. The temperature of the plate is measured at the center using a filament T-type thermocouple probe. Once the plate has reached the desired starting temperature, the animals are tested as described above. This assay allows testing of mice at temperatures ranging from innocuous to noxious. The CPA yields unambiguous and consistent behavioral responses in uninjured mice and can be used to quantify both hypersensitivity and analgesia. This protocol describes how to use the CPA to measure cold hypersensitivity, analgesia, and adaptation in mice.

Suppression effect of decarburization by dry-ice blasting on plasma-sprayed steel coatings: Structure, wear performance and magnetic properties

Steel coatings prepared by atmospheric thermal spraying with dry-ice blasting were studied in terms of phase structure, magnetic and wear behaviors. It was found that dry-ice blasting could suppress the volatilization of carbon during spraying process due to the exclusion effect of carbon dioxide gas sublimated from dry-ice pellets on the oxygen. Moreover, the fractographic observation of the deposited coatings proved the removal effect of dry-ice blasting on the splashing particulates which were distributed with poor bonding strength between the splat layers. In addition, it has been found that the magnetic properties are sensitive to the direction in the coating, although steel coating presents a ferromagnetic character in the parallel and vertical directions. Steel coating deposited with dry-ice blasting possesses a relatively lower saturation magnetization but has a superior wear resistance because of the suppression of decarburization during the spraying process.

Microstructure and properties of Cr2O3 coating deposited by plasma spraying and dry-ice blasting

Dry-ice blasting is applied in atmospheric plasma spray process with an aim to improve the properties of Cr2O3 coatings and save the cost. Microstructure, the tensile adhesive strength and the wear resistance of plasma-sprayed Cr2O3 coatings without and with the treatment of dry-ice blasting were compared. The results indicate that dry-ice blasting has a significant effect on the porosity of Cr2O3 coating. After the treatment of dry-ice blasting, the porosity of Cr2O3 coating decreases from 6.6±1.1% to 2.0±0.1% and a noticeable improvement in the adhesion between the coating and 25CrMo4 substrate has been obtained from 13±2MPa to 46±5MPa. They could be attributed to the sublimation effect of dry-ice pellets on the evaporated Cr and the cleaning effect of dry-ice blasting on the coated substrate. The dry-ice blasted coating was more wear resistant than that deposited without dry-ice blasting.

Effect of Dry-Ice Blasting on the Microstructure and Properties of Plasma-Sprayed CoNiCrAlY Coating

Depending on the oxidation extent and the surface roughness after coating manufacturing, CoNiCrAlY coating displays different performance in thermal barrier coating systems. In this study, plasma-sprayed CoNiCrAlY coatings were treated by dry-ice blasting. Various treatment approaches of dry-ice blasting were assessed by means of comparing the coating quality in terms of cross-sectional structure, oxide concentration, surface morphology and roughness, and microhardness. The results showed that CoNiCrAlY coating including decreased oxides and smoother internal texture can be obtained in comparison with that deposited by conventional APS, no matter what type of treatment. The oxidation content differ after using different jet angle and installation location of dry-ice blasting. To some extent, dry-ice blasting has some cleaning effect on those splashed particles. However, no much change can be recognized in the top-surface morpholgy and surface roughness, because of the relatively small hardness of dry-ice pellets. There is a slight decrease in hardness probably resulting from the decrease in the oxide.

Dry-ice Pellet Cleaning 적용 옥외 금속문화재 표면 페인트 및 유성물질 제거방법 비교 연구

문화재의 훼손은 다양한 형태로 발생된다. 특히 옥외에 노출되어 있는 금속문화재의 표면 손상은 인위적인 훼손인 페인트나 유성물질 성분의 낙서 등과 같은 행위로 유물의 역사적, 미술사적 가치를 저하시킨다. 그러므로 본 연구에서는 친환경적이고 인체에 무해한 dry-ice pellet cleaning을 페인트 및 유성물질을 제거하는데 적용하였으며 결과를 습포법과 비교하였다. 실험 결과 습포법으로 제거할 경우 유성페인트는 제거는 되었으나 금속 표면에 얼룩이 남아 있었으며 락카 스프레이는 제거가 잘 이루어지지 않고 수지가 들떠 있는 현상이 나타났다. Dry-ice pellet cleaning으로 유성페인트를 제거한 경우 표면관찰, 색도계, FT-IR, SEM 분석을 통해 유물 표면에 손상 없이 깨끗하게 제거되었으며 락카 스프레이로 제거한 경우 육안 관찰로는 깨끗하였으나 SEM 관찰 결과 미세 입자가 표면에 남아있는 것이 관찰되었다. 그러므로 본 연구를 통해 dry-ice pellet cleaning의 대체 가능성과 한계성을 함께 확인할 수 있었다. Damage of cultural properties happens variously. Particularly, the surface damage of metal cultural properties exposed outdoors lowers historical and art historical value of artifact by artificial damage such as paint, scribbling containing oily material and so on. Therefore, this study compared dry-ice pellet cleaning with poultice when clearing paint and oily material environment-friendly, harmlessly to humans and without damage of artifact. As the result of experiment, when clearing those (paint and oily material) by poultice, oily paint was cleared, but there were spots of metal surface. Also, Lacquer spray wasn't well cleared, and resin came off the surface of artifact. When clearing those by dry-ice pellet cleaning, oil paint was cleanly cleared without surface damage of artifact according to Stereoscopic microscope observation, color-measurement, FT-IR, SEM analysis. Also, lacquer spray seemed to be cleared with the naked eye, but there were minute particles on surface according to the result of SEM observation. Consequently, we could confirm possibility of dry-ice pellet cleaning substitution.

A novel behavioral assay for measuring cold sensation in mice.

Behavioral models of cold responses are important tools for exploring the molecular mechanisms of cold sensation. To complement the currently cold behavioral assays and allow further studies of these mechanisms, we have developed a new technique to measure the cold response threshold, the cold plantar assay. In this assay, animals are acclimated on a glass plate and a cold stimulus is applied to the hindpaw through the glass using a pellet of compressed dry ice. The latency to withdrawal from the cooled glass is used as a measure of the cold response threshold of the rodents, and the dry ice pellet provides a ramping cold stimulus on the glass that allows the correlation of withdrawal latency values to rough estimates of the cold response threshold temperature. The assay is highly sensitive to manipulations including morphine-induced analgesia, Complete Freund's Adjuvant-induced inflammatory allodynia, and Spinal Nerve Ligation-induced neuropathic allodynia.