Total Plastic Research Articles

Advancing biopharmaceutical manufacturing: economic and sustainability assessment of end-to-end continuous production of monoclonal antibodies

Monoclonal antibodies (mAbs) have become essential therapeutics for treating various diseases. The robust, cost-effective, and sustainable production of mAbs is crucial due to their growing clinical and commercial demand. Advances in bioprocessing, such as improved cell lines, perfusion bioreactors, multicolumn chromatography, and automation, can significantly increase productivity, making treatments more accessible. Streamlining the production process also aligns with environmental sustainability by reducing waste and energy consumption. This study quantifies the economic and environmental impacts of incorporating recent advances into end-to-end continuous bioprocessing of mAbs. The results demonstrate that, compared with an optimized best-in-class fed-batch process (with 15 g/l titer and multicolumn chromatography), continuous manufacturing can reduce the total annual production costs, facility footprint, plastic waste, and CO2 emissions by up to 23%, 51%, 57%, and 54%, respectively, in a producing clinical and commercial lots. Additionally, uncertainty analysis indicates that these gains are even more substantial under demand fluctuations.

Analysis of high temperature and strain amplitude effects on low cycle fatigue behavior of pitting corroded killed E350 BR structural steel

High-tension structural steels are prone to accelerated fatigue damage from pitting corrosion and high-temperature. Despite adverse effects, research on their low cycle fatigue (LCF) behavior is limited. Specifically, studies analyzing temperature-dependent pit sensitivity effects, considering pit-related material’s susceptibility to surface topographic features variation and stress concentration are lacking. This study conducts LCF tests on pitting corroded killed E350 BR structural steel at multiple strain amplitudes and high temperatures. It develops temperature-dependent parameters, such as the cyclic softening pit sensitivity factor, suitable for integration into existing approaches like total cyclic plastic strain energy density (CPSED), power-law, average strain energy density (SED), Coffin-Manson, and pit stress intensity factor (pit-SIF). Further, it proposes multiple linear regression-based prediction models relating total CPSED and average SED with strain amplitude and temperature. Corroded specimens show higher plastic deformation and reduced peak stress, fatigue life, and total CPSED compared to uncorroded ones. The developed parameters, integrated with average SED approach, predicts LCF life within an error band of ±1.5, while power-law relationship reduces it to ±1.2. Moreover, pit-SIF approach estimates fatigue life within an error band of ±1.5. The findings provide critical knowledge for enhanced component design, leading to structural safety, performance, and fire resilience.

Plastics in the Indian economy: a comprehensive material flow analysis

AbstractPlastic is valued for its flexibility to be utilized in different applications, yet it poses a significant threat to our environment because of mismanaged plastic waste. India’s compound annual growth of plastic consumption has been around 7% for a decade. Despite this significant growth, there has not been a comprehensive study of Indian plastic flows since 2000. This work presents a 20-year update, detailing plastic production, consumption by all plastic types and sectors, and the overall material flow for 2018–19 to fill the gap in the data on post-consumer plastic flows. The analysis reveals a total plastic production of 19.3 Mt, 22% of which is Polyethylene as the most wildly used plastic. The total mass of plastic in products distributed in various applications is 23.9 Mt. Key sectors for plastic consumption are Packaging (30%), Textiles (17%), and Buildings and Construction (16%). Plastic waste generation is 15.5 Mt, primarily from packaging and textiles. Only 13% of this plastic gets recycled, 46% is mismanaged, and the rest incinerated or dumped. The study’s unique nationwide, mass-balanced, transparent approach offers a rigorous reference point for decision-makers. Yet, the lack of reliable data is the main barrier to design, implement, and monitor of policy interventions.

Unaccounted plastic: Estimating waste generation from marine vessels in Bangladesh

Solid waste mismanagement induces the release of a significant amount of plastic waste into the ocean, particularly in countries with poor solid waste management systems, such as Bangladesh. Nevertheless, the total plastic input of Bangladesh by multiple sources is still unknown. Waste input from land-based sources within 50 km coastline of this country is documented. However, the quantity of plastic entering the oceans from multiple sources, such as marine vessels, is still unknown and not documented. Passengers and goods are transported via marine vessels operating in Bangladesh's Inland Water Transport sector, which has the potential to generate a substantial quantity of plastic debris that remains unaccounted for. This study represented the initial attempt to quantify the amount of debris produced by passenger-carrying marine vessels in riverine systems. The estimated total amount of plastic waste generated per day per route from marine vessels stands at 76.6 kg. The total weight of plastic waste from all pathways was 436.3 kg, resulting in an estimated annual plastic waste generation of 157,068 kg. This yearly input is 0.6 % of Bangladesh's total mismanaged waste input into the Bay of Bengal, which is 0.79 million metric tonnes. The lack of implementation of regulatory measures and ineffective waste management systems can be pointed out as the main reason behind these plastic inputs. This paper identifies the current gaps in waste management practices for riverine plastic waste and is a forerunner to creating a baseline for unified policy formulation for the government.

Synergistic Enhancement of Mechanical Properties and Electrical Conductivity of Immiscible Bimetal: A Case Study on W–Cu

Immiscible bimetal systems, of which tungsten–copper (W–Cu) is a typical representative, have crucial applications in fields requiring both mechanical and physical properties. Nevertheless, it is a major challenge to determine how to give full play to the advantages of the two phases of the bimetal and achieve outstanding comprehensive properties. In this study, an ultrafine-grained W–Cu bimetal with spatially connected Cu and specific W islands was fabricated through a designed powder-mixing process and subsequent rapid low-temperature sintering. The prepared bimetal concurrently has a high yield strength, large plastic strain, and high electrical conductivity. The stress distribution and strain response of individual phases in different types of W–Cu bimetals under loading were quantified by means of a simulation. The high yield strength of the reported bimetal results from the microstructure refinement and high contiguity of the grains in the W islands, which enhance the contribution of W to the total plastic deformation of the bimetal. The high electrical conductivity is attributed to the increased mean free path of the Cu and the reduced proportion of phase boundaries due to the specific phase combination of W islands and Cu. This work provides new insight into modulating phase configuration in immiscible metallic composites to achieve high-level multi-objective properties.

Hydrogen embrittlement of Zircaloy-4 fabricated by ultrasonic additive manufacturing

Ultrasonic additive manufacturing (UAM) was successfully applied to the zirconium material system to create a planar geometry. Following fabrication, SS-J3 type tensile specimens of the UAM and wrought Zircaloy-4 with a nominal gage section of 5 × 1.2 × 0.75 mm were machined for hydriding studies and mechanical testing. The SS-J3 type tensile specimens were gas-charged with hydrogen using a custom system that precisely controls hydrogen gas flow rate, hydrogen partial pressure, and temperature. To avoid altering the UAM material, the maximum process temperature was limited to 550 °C. Using different initial hydrogen gas pressures and flow rates, various hydrogen contents (70–1755 wppm) were achieved for Zircaloy-4 specimens. Tensile testing shows that, regardless of hydrogen content, all UAM specimens measured yield strengths in the range of 557 ± 16 MPa and ultimate tensile strengths of 660 ± 4 MPa. However, total elongation clearly decreased as a function of increasing hydrogen content. At the lowest hydrogen content, the total plastic elongation measured 21.5 %, and this value decreased to less than 2 % when the hydrogen content was increased to 1000 wppm. Cross-sectional optical microscopy images revealed that the hydride distributions are randomly oriented. For the low hydrogen content specimen, these randomly distributed hydrides are isolated from each other. A sandwiched structure, consisting of high-density and low-density layers, was also observed for the specimens with hydrogen content between 200 and 400 wppm. As the hydrogen content increases, the hydrides diffuse into the low-density hydride layers to form a network across the whole specimen. Although the tensile properties of UAM and wrought Zircaloy-4 exhibit the same behavior with increasing hydrogen content, the distinctions in grain orientations led to differences in the hydride orientations at low and intermediate hydrogen concentrations.

Addressing plastic pollution and waste flows: Insights from South Africa's experience.

The Pew Charitable Trust's 2020 report 'Breaking the Plastic Wave', indicates that existing technologies could support an 80% reduction in plastic leakage relative to business as usual by 2040. Therefore, South Africa became the first country to work with the Pew Charitable Trust and Oxford University to test and apply 'Pathways', a modelling framework and software tool which stemmed and evolved from the Pew report, at country level. The tool calculates the flows of plastics in the economy and the impact of various strategies to reduce future plastic pollution. The Scenario Builder within the Pathways tool allows the user to optimise flows in the plastics value chain to satisfy a set of defined objectives in order to achieve an optimal solution. Three major findings have emerged from the application of Pathways at country level for South Africa. Firstly, plastic pollution is set to almost double by 2040 if no interventions are implemented. Secondly, meeting the newly legislated extended producer responsibility (EPR) targets set for plastic packaging can avoid 33% of projected total pollution over the period of 2023-2040. Lastly, an optimal system change can avoid 63% of total plastic pollution over the period 2023-2040. Thus, applying Pathways at country level in South Africa has proven to be valuable by setting a baseline against which progress towards reducing plastic pollution can be measured; determining the outcome of meeting the legislated EPR targets over time, and informing policy decisions by allowing users to model different scenarios towards an optimal system change scenario.

Using the Amount of Plastic Packaging Placed on the Market to Determine the Annual Amount of Plastic Packaging Waste Generated in Poland to Enable Sustainable Waste Management

A new category of own resources based on national contributions, which are calculated on the basis of the amount of non-recycled plastic packaging waste (PPW) (EUR 0.80 per kilogram), was introduced in 2021 by the decision of the EU Council (EU, Euratom, 2020/2053). In accordance with the European strategy for plastics, the Union budget can contribute to reducing pollution from PPW, which is consistent with sustainable waste management. To calculate the own resource of plastics, it is necessary to determine the amount of non-recycled PPW by taking the difference between the amounts of generated and recycled PPW. Data on the amount of recycled PPW can be obtained from recycling facilities. The challenge, however, is to determine the actual amount of PPW generated in a given year. For this reason, the present study was undertaken to determine the amount of PPW generated annually, based on the amount of plastic packaging placed on the market (PPM) (i.e., with the use of the placed-on-the-market approach). To perform the calculations, the Polish entities that place products in plastic packaging on the market were identified. It was assumed that the amount of PPM was the sum of the amounts of packaging stated by producer responsibility organizations (PRO), as well as self-compliers (SC), private imports (I), and free-riders (FR), minus the amount of packaging privately exported (E). To obtain the relevant data from the records linked to the amounts of plastic packaging imported to and exported from Poland, a detailed methodology was developed. A complementary analysis was concurrently conducted to estimate the amount of plastic PPM by free-riders. The results of these analyses indicate that the amount of packaging transparently reported by the PRO accounted for almost 97% of the total amount of PPM. The analysis found 19,728 SC who placed 2.22% of the total plastic packaging on the market. The total amount of privately imported plastic packaging was 17,304,666 kg (1.37%). Plastic packaging placed on the market by FR is 24,788,196 kg (1.97%). However, the amount of plastic packaging privately exported was 30,571,691 kg (2.43%). Thus, in 2021, the amount of plastic packaging placed on the Polish market was 1,259,345,296 kg; this figure constitutes the basis for determining the own resources based on non-recycled PPW. It also indicates the potential of PPW to serve as a resource for the production of new products, which is in accordance with the principles of a circular economy.

Modeling multi-source plastic pollution yield and transport driven by catchment hydrometeorological processes

Plastic pollution has emerged as a global environmental concern, impacting both terrestrial and marine ecosystems. However, understanding of plastic sources and transport mechanism at the catchment scale remains limited. This study introduces a multi-source plastic yield and transport model, which integrates catchment economic activities, climate data, and hydrological processes. Model parameters were calibrated using a combination of field observations, existing literature, and statistical random sampling techniques. The model demonstrated robust performance in simulating both plastic yield and transport from 2010 to 2020 in the upper and middle Mulan River Catchment, located in southeast China. The annual average yield coefficients were found to closely align with existing estimations, and the riverine outflow exhibited a high correlation coefficient of 0.97, with biases ranging from -63.0 % to -21.4 % across all monitoring stations. The analysis reveals that, on average, 12.5 ± 2.5 % of the total plastic yield is transported to rivers annually, with solid waste identified as the primary source, accounting for 37.8 ± 20.7 % of the total load to rivers, followed by agricultural film (26.4 ± 9.8 %), impermeable surfaces (21.5 ± 10.3 %), urban and rural sewage (10.4 ± 5.0 % and 3.0 ± 1.5 %, respectively), and industrial wastewater (0.9 ± 0.7 %). The annual average outflow was estimated to between 9.3 and 43.0 ton/year (median: 23.1) at a 95 % confidence level. This study not only provides insights into the primary sources and transport pathways of plastic pollution at the catchment scale, but also offers a valuable tool for informing effective plastic pollution mitigation strategies.

Microplastic concentration, characterization, and size distribution in the Delaware Bay estuary

Microplastic (MP) pollution has been widely reported across water matrices including in estuaries, which are important for the understanding of oceanic MPs. Estuaries can greatly alter the fate, transport, size distribution, and abundance of plastic pollution. The aim of this study was to quantify and characterize MP pollution in the Delaware Bay estuary USA, including the size distribution. Samples (N = 31) were collected from the mouth of the Delaware River to the coastal ocean including multiple frontal zones across two sampling campaigns (2019 and 2022). MP were extracted from the collected particles using wet peroxide oxidation and density separation with saturated sodium chloride. Particles collected on 500 μm mesh sieves were analyzed via Fourier transform infrared (FTIR) spectroscopy. Across all samples, 324 of the 1015 particles analyzed were MP, and 11 macroplastics were observed. MP concentrations ranged from below detection to 4.12 MP/m3 (mean 0.34 ± 0.80 MP/m3). No significant differences were observed between sampling sites; nonetheless, the two highest MP concentrations were observed when sampling along frontal zones with visible debris including macroplastics. Polyethylene (53%) and polypropylene (43%) were the most abundant polymers observed. The majority of the non-plastic particles were classified as particulate natural organic matter (82% of non-plastics). Particles from samples collected during 2022 (N = 864) also had color, morphology, and two size dimensions recorded. MP particle size was significantly associated with sampling site, with the coastal ocean sampling site generally having the smallest MPs. A correlation between total post-extraction particles and total plastic particles was observed. Aspect ratios for the plastics ranged from one to 40.7, with larger ratios for fibers, with a mean (±standard deviation) of 3.39 ± 4.72 (unitless). These aspect ratios can be used to select shape factors used to estimate the total volume of MP in the studied size range. Overall, these results can help inform fate, transport, and risk assessments related to estuarine plastic pollution.

Utilizing PET bottles for sustainable cellular reinforcement: A study on enhancing fly ash backfill bearing strength with innovative geocell alternative

The slow degradation rate is one of the major global concerns. Only, 60 % produced is being recycled. Among these waste materials, Polyethylene Terephthalate (PET) bottles contribute around 10 % to the total plastic waste produced. The recycling process of PET bottles considering existing capacity in environmentally responsible ways is limited. It is estimated that 60 % of PET bottles produced are being disposed of in landfills. To overcome this, past studies have suggested novel approaches for using it as substitute for conventional geocell as soil reinforcement and stability. However, past studies mostly focused on application of PET bottles as flaked, shreds and sliced form. The present study attempts on application of PET bottles under fly ash (FA) backfills without mechanical alterations. Full-scale experiments were conducted on FA backfill system, for both unreinforced and reinforced conditions. A comparative study was performed between high-density polyethylene (HDPE) geocell and PET bottle mattress to assess the bearing strength of the FA backfill. Experiments were performed in a 1 m3 tank with a loading plate width of 200 mm. Vertical loading was applied onto the backfill footing (for all the trial series), till the footing settlement of 40 mm is achieved. An aspect ratio of 2 was considered for HDPE geocell and PET bottles. Rock quarry dust (RQD) was considered as cell infill and overlay material on FA backfill. The test results showed that settlement accumulation rate was low under reinforced scenario compared to the unreinforced condition, with higher resilient (elastic) settlement. RQD over the PET-reinforced zone was also seen to have enhanced the load distribution aspect, thereby reducing deformation in PET reinforcement. This usage of waste material will contribute towards sustainable development. This work demonstrates the feasibility and effectiveness of PET reinforcement to be used as replacement for HDPE geocell, which eventually can agument the design methodology of structural backfills.

Defining plastic pollution hotspots

Plastic pollution in the natural environment poses a growing threat to ecosystems and human health, prompting urgent needs for monitoring, prevention and clean-up measures, and new policies. To effectively prioritize resource allocation and mitigation strategies, it is key to identify and define plastic hotspots. UNEP's draft global agreement on plastic pollution mandates prioritizing hotspots, suggesting a potential need for a defined term. Yet, the delineation of hotspots varies considerably across plastic pollution studies, and a definition is often lacking or inconsistent without a clear purpose and boundaries of the term. In this paper, we applied four common definitions of hotspot locations to plastic pollution datasets ranging from urban areas to a global scale. Our findings reveal that these hotspot definitions encompass between 0.8 % to 93.3 % of the total plastic pollution, covering <0.1 % to 50.3 % of the total locations. Given this wide range of results and the possibility of temporal inconsistency in hotspots, we emphasize the need for fit-for-purpose criteria and a unified approach to defining plastic hotspots. Therefore, we designed a step-wise framework to define hotspots by determining the purpose, units, spatial scale, temporal scale, and threshold values. Incorporating these steps in research and policymaking yields a harmonized definition of hotspots, facilitating the development of effective plastic pollution prevention and reduction measures.

From Polyester Plastics to Diverse Monomers via Low-Energy Upcycling.

Polyester plastics, constituting over 10% of the total plastic production, are widely used in packaging, fiber, single-use beverage bottles, etc. However, their current depolymerization processes face challenges such as non-broad spectrum recyclability, lack of diversified high-value-added depolymerization products, and crucially high energy consumption. Herein, an efficient strategy is developed for dismantling the compact structure of polyester plastics to achieve diverse monomer recovery. Polyester plastics undergo swelling and decrystallization with a low depolymerization energy barrier via synergistic effects of polyfluorine/hydrogen bonding, which is further demonstrated via density functional theory calculations. The swelling process is elucidated through scanning electron microscopy analysis. Obvious destruction of the crystalline region is demonstrated through X-ray crystal diffractometry curves. PET undergoes different aminolysis efficiently, yielding nine corresponding high-value-added monomers via low-energy upcycling. Furthermore, four types of polyester plastics and five types of blended polyester plastics are closed-loop recycled, affording diverse monomers with exceeding 90% yields. Kilogram-scale depolymerization of real polyethylene terephthalate (PET) waste plastics is successfully achieved with a 96% yield.

Characterization and distribution of macroplastics along the coastal municipalities of Partido district, Camarines Sur, Philippines

This study was conducted to characterize and investigate the distribution of macroplastics in the nine coastal municipalities of Partido district, Camarines Sur, Philippines. The study aimed to quantify and categorize the macroplastics along the coastal areas of the study site. The results reveal variations in the type, color, size, category, and amount of plastic waste among different municipalities. Notably, plastic fragments, cigarette butt, food packaging, and disposable utensils emerged as the predominant forms of macroplastics within the study area. The majority of the collected plastic particles fell within the size range of 0.5–1.00 cm, while transparent, white, and green were identified as the prevailing colors in the samples of plastic waste. Furthermore, both hard plastic and soft plastic fragments were frequently encountered, accounting for 35% and 31% of the total plastic, respectively. Sagňay, Tigaon, and Caramoan exhibited the highest densities of macroplastics, with values of 0.62±0.11, 0.60±0.05, and 0.59±0.06 pcs/m2, respectively. In contrast, Garchitorena displayed the lowest density at 0.26±0.04. The remaining municipalities exhibited densities ranging from 0.4 to 0.5 pcs/m2. The elevated macroplastics density observed can be attributed to factors such as their degree of urbanization, tourist activity, and population density. The findings of this study provide valuable insights into the composition and characteristics of macroplastics found along the coastal municipalities of Partido district, emphasizing the urgent need for effective strategies and policies to mitigate the possible impact to the environment.

Handling 'carbon footprint' in orthopaedics.

The National Health Service contributes 4%-5% of England and Wales' greenhouse gases and a quarter of all public sector waste. Between 20% and 33% of healthcare waste originates from a hospital's operating room, and up to 90% of waste is sent for costly and unneeded hazardous waste processing. The goal of this study was to quantify the amount and type of waste produced during a selection of common trauma and elective orthopaedic operations, and to calculate the carbon footprint of processing the waste. Waste generated for both elective and trauma procedures was separated primarily into clean and contaminated, paper or plastic, and then weighed. The annual carbon footprint for each operation at each site was subsequently calculated. Elective procedures can generate up to 16.5kg of plastic waste per procedure. Practices such as double-draping the patient contribute to increasing the quantity of waste. Over the procedures analysed, the mean total plastic waste at the hospital sites varied from 6 to 12kg. One hospital site undertook a pilot of switching disposable gowns for reusable ones with a subsequent reduction of 66% in the carbon footprint and a cost saving of £13,483.89. This study sheds new light on the environmental impact of waste produced during trauma and elective orthopaedic procedures. Mitigating the environmental impact of the operating room requires a collective drive for a culture change to sustainability and social responsibility. Each clinician can have an impact upon the carbon footprint of their operating theatre.

Effect of Operational Variables on Supercritical Foaming of Caffeic Acid-Loaded Poly(lactic acid)/Poly(butylene adipate-co-terephthalate) Blends for the Development of Sustainable Materials.

Expanded polystyrene will account for 5.3% of total global plastic production in 2021 and is widely used for food packaging due to its excellent moisture resistance and thermal insulation. However, some of these packages are often used only once before being discarded, generating large amounts of environmentally harmful plastic waste. A very attractive alternative to the conventional methods used for polymer processing is the use of supercritical carbon dioxide (scCO2) since it has mass-transfer properties adapted to the foam morphology, generating different path lengths for the diffusion of active compounds within its structure and can dissolve a wide range of organic molecules under supercritical conditions. The objective of this research was to evaluate the effect of operational variables on the process of caffeic acid (CA) impregnation and subsequent foaming of polylactic acid (PLA) as well as two PLA/poly(butylene-co-terephthalate-adipate) (PBAT) blends using scCO2. The results showed an increase in the degree of crystallinity of the CA-impregnated samples due to the nucleation effect of the active compound. On the other hand, SEM micrographs of both films and foams showed significant differences due to the presence of PBAT and its low miscibility with PLA. Finally, the results obtained in this work contribute to the knowledge of the important parameters to consider for the implementation of the impregnation and foaming process of PLA and PLA/PBAT blends with potential use in food packaging.

Sunlight-Driven Photochemical Removal of Polypropylene Microplastics from Surface Waters Follows Linear Kinetics and Does Not Result in Fragmentation.

Floating microplastics are susceptible to sunlight-driven photodegradation, which can convert plastic carbon to dissolved organic carbon (DOC) and can facilitate microplastic fragmentation by mechanical forces. To understand the photochemical fate of sub-millimeter buoyant plastics, ∼0.6 mm polypropylene microplastics were photodegraded while tracking plastic mass, carbon, and particle size distributions. Plastic mass loss and carbon loss followed linear kinetics. At most time points DOC accumulation accounted for under 50% of the total plastic carbon lost. DOC accumulation followed sigmoidal kinetics, not the exponential kinetics previously reported for shorter irradiations. Thus, we suggest that estimates of plastic lifespan based on exponential DOC accumulation are inaccurate. Instead, linear plastic-C mass and plastic mass loss kinetics should be used, and these methods result in longer estimates of photochemical lifetimes for plastics in surface waters. Scanning electron microscopy revealed that photoirradiation produced two distinct patterns of cracking on the particles. However, size distribution analyses indicated that fragmentation was minimal. Instead, the initial population of microplastics shrank in size during irradiations, indicating photoirradiation in tranquil waters (i.e., without mechanical forcing) dissolved sub-millimeter plastics without fragmentation.

Environmental performance of different water bottles with different compositions: A cradle to gate approach

Plastic production has increased over the years and the packaging industry was responsible for 44% of the total plastic production. Polyethylene terephthalate (PET), due to its favorable properties, is one of the most used polymers in this sector.This study first aimed to compare the environmental performance related to the production of a novel recycled PET (rPET) form, namely, rPET flake, and then compare it with the production of virgin PET (vPET) and rPET pellet. Secondly, this study aimed to compare the environmental impacts of four water bottles with different compositions, namely, option A composed with only vPET, option B made with 50% vPET and 50% rPET pellet, option C made with 75% rPET pellet and 25% rPET flake, and option D made with 50% vPET, 25% rPET pellet and 25% rPET flake. Option A was designed as a single-use water bottle, while the remaining options (Options B, C and D) were thought to be reusable bottles, and for that reason were heavier and more robust compared to Option A. The environmental impact assessment followed the International Standard Rules of Life Cycle Assessment (LCA), and the impact assessment method used was the Environmental Product Declaration. Ecoibéria and Logoplaste provided the majority of the required data, and three functional units were considered. The first one was the production of 1 kg of PET, the second was the production of different water bottles, and finally, the third one was the consumption of 2 l of water with different water bottles. As a result, it was first observed that the production of rPET flake in comparison to vPET reduces, on average, 79% of the impacts, and rPET pellet reduces 10% of the impacts. Secondly, in the production of the different water bottles, Option A, the single-use bottle, presented the lowest environmental impacts in almost all categories. Finally, when taking into account the reusable factor, the use of single-use bottles presented the higher environmental impact in all categories, probably because of the dilution of the environmental impacts associated with the production of heavier and robust reusable bottles by the multiple times of uses of these bottles.

Lifetime Prediction Method of the Traction Converter IGBT Based on Plastic Strain Energy Density

Insulated gate bipolar transistor (IGBT) is the most important power electronic component in the traction converters of trains. During the operation of the IGBT, the solder layer is continuously subjected to alternating stress, which eventually leads to the fatigue failure of the solder layer. Therefore, an accurate assessment of the lifetime of the IGBT module solder layer is of great importance for the safe and reliable operation of the trains. Firstly, the micromechanism of the plastic deformation of the base solder layer of the IGBT module is introduced, as well as the lifetime model based on the plastic strain energy density. Then the total plastic strain energy density of the base solder layer is determined by conducting the accelerated aging tests on the IGBT module and combining the finite element simulation results. Meanwhile, the relationship between different aging degrees of the base solder layer of the IGBT module and the plastic strain energy density is studied by finite element simulation. Then, the lifetime of the base solder layer at different aging stages is calculated based on the above results so that the total lifetime of the IGBT module is obtained. Finally, the predicted lifetime of the IGBT module by the proposed method is compared with the lifetime obtained by the accelerated aging test and compared with the traditional lifetime prediction method based on the Coffin-Manson-Arrhenius model. The comparison results verify the accuracy of the proposed lifetime prediction method in this paper.

River plastic transport affected by tidal dynamics

Abstract. Plastic is an emerging pollutant, and the quantities in rivers and oceans are expected to increase. Rivers are assumed to transport land-based plastic into the ocean, and the fluvial and marine transport processes have been relatively well studied to date. However, the processes controlling the transport in tidal rivers and estuaries, the interface between fluvial and marine systems, remain largely unresolved. For this reason, current estimates of riverine plastic pollution and export into the ocean remain highly uncertain. Hydrodynamics in tidal rivers and estuaries are influenced by tides and freshwater discharge. As a consequence, flow velocity direction and magnitude can change diurnally. In turn, this impacts the transport dynamics of solutes and pollutants, including plastics. Plastic transport dynamics in tidal rivers and estuaries remain understudied, yet the available observations suggest that plastics can be retained here for long time periods, especially during periods of low net discharge. Additional factors such as riparian vegetation and riverbank characteristics, in combination with bi-directional flows and varying water levels, can lead to an even higher likelihood of long-term retention. Here, we provide a first observation-based estimate of net plastic transport on a daily timescale in tidal rivers. For this purpose, we developed a simple Eulerian approach using sub-hourly observations of plastic transport and discharge during full tidal cycles. We applied our method to the highly polluted Saigon River, Vietnam, throughout six full tidal cycles in May 2022. We show that the net plastic transport is about 20 %–33 % of the total plastic transport. We found that plastic transport and river discharge are positively and significantly correlated (Pearson's R2 = 0.76). The net transport of plastic is higher than the net discharge (20 %–33 % and 16 %, respectively), suggesting that plastic transport is governed by factors other than water flow. Such factors include wind, varying plastic concentrations in the water, and entrapment of plastics downstream of the measurement site. The plastic net transport rates alternate between positive (seaward) net transport and negative (landward) net transport as a result of the diurnal inequality in the tidal cycles. We found that soft and neutrally buoyant items had considerably lower net transport rates than rigid and highly buoyant items (10 %–16 % vs. 30 %–38 %), suggesting that transport dynamics strongly depend on item characteristics. Our results demonstrate the crucial role of tidal dynamics and bi-directional flows in plastic transport dynamics. With this paper we emphasize the importance of understanding fundamental transport dynamics in tidal rivers and estuaries to ultimately reduce the uncertainties of plastic emission estimates into the ocean.