Plastic Sorting Research Articles

Outlining a comprehensive techno-economic approach to evaluate the performance of an advanced sorting plant for plastic waste recovery

Mixed plastics from municipal solid waste are usually recycled in suitable Material Recovery Facilities (MRFs) following separate collection. These plants allow the sorting of individual plastics with variable performance depending on the technologies adopted. The evaluation of the performance of MRFs is also conducted with different approaches, even in terms of timescales, making the results difficult to compare. In this context, this study presents a comprehensive techno-economic approach to evaluate the performance of a MRF for plastic waste recovery. As a support, the Molfetta MRF case study (Southern Italy) was considered with an inlet plastic amount of about 19,000 t/year. The methodological proposal was based on the analysis of the quantity and composition of the different incoming waste streams, calculation of the Purity Index (PI) and Recovery Index (RI), quantification of the mass balance as well as accurate economic assessment. PI and RI assess the technical performance of the facility. They achieved the highest values (>95 %) for manual and optical sorting indeed they reached good values (70–80 %) for dimensional one; the economic analysis showed a specific gain of 12.58 €/t of sorted waste. The comparison of the obtained results with those of a similar MRF in Northern Italy had corroborated the suitability of the proposed approach suggesting its application, although with the due exceptions referred to the economic part, to other world contexts.

Experimental and statistical study of the effect of temperature and waste ratio on the mechanical properties and cost of polystyrene polypropylene plastic blends

Since most plastics are not biodegradable, plastic recycling is the main part of global efforts to reduce plastic in the waste stream. Sorting of plastics imposes lots of difficulties which can be avoided by introducing plastic blends. This paper starts by reviewing the recent attempts to study plastic blends. Accordingly, the purpose of this study is to analyze experimental results and apply statistical measures using ANOVA to study the effect of increasing the waste ratio that contains both waste polystyrene and polypropylene on the mechanical properties of pure polystyrene when injected at different temperatures. Cost is taken as a response factor to analyze whether the degradation of mechanical properties is justified by a decrease in cost. As expected, cost dramatically decreases with increasing the waste ratio at any temperature. Increasing the waste ratio resulted in better mechanical properties with a maximum at a 30% waste ratio at 200 °C and 220 °C. This paper ends with a multi-objective optimization analysis that helps decision-makers optimize the properties needed of the studied plastic blend by controlling both the temperature and waste ratio.

Radiolysis as a Powerful Tool for Polymer Waste Recycling

The review is devoted to the use of ionizing radiation for the processing of polymer wastes including the application of radiolytic effects to the sorting of plastics; an increase in the compatibility of plastics with cement, asphalt, and other materials; the destruction of high-molecular-weight wastes; the synthesis of multicomponent polymer composites; the production of monomers for the synthesis of conventional and alternative plastics; the manufacture of antioxidants; the processing of inseparable mixtures of natural and synthetic polymers; etc. The radiation-induced processes of crosslinking, graft polymerization, oxidation, degradation, and high-temperature conversion in the recycling of polymer wastes are considered.

Classification-based material decomposition method for photon counting-based spectral radiography: Application to plastic sorting

Dual-energy X-ray radiography has been commonly used for materials separation. However, its performance is limited, especially for the separation of close materials or the identification of multiple materials. To cope with this problem, we propose to investigate the material decomposition ability of spectral radiography based on photon-counting detector. The latter having energy resolving capability can provide spectral information of several energy bins and thus enables selective imaging of multiple materials. In this framework, a classification-based patchwise regularized decomposition method was proposed to gain better differentiation between materials. It consists of performing several decompositions with reduced number of materials in the basis and classifying these decompositions using their cost function values. The results on simulations showed that, in the presence of Poisson noise, the method without classification can separate acrylonitrile-butadiene-styrene (ABS) from three kinds of flame retardants (FRs: brominated FR, chlorinated FR and phosphorus FR), but that the type of FR cannot be identified. With the classification technique, ABS and three kinds of FRs can be both separated and identified at the same time when the thickness was as large as 2 mm or 4 mm. The results on real data from physical photon-counting detector further confirm that the ABS, Br and Cl can be separated from each other.

Environmental evaluation of distributed versus centralized plastic waste recycling: Integrating life cycle assessment and agent-based modeling

Abstract Plastic waste is internationally recognized as a problem, fueled by increased public awareness of environmental concerns and the steady increase in waste import bans. Modern sorting and recycling technologies are mature, but face implementation limitations in highly dense urbanized regions such as Singapore due to significant space constraints and expensive labor. Distributed plastic sorting and recycling facilities at small-scale closer to points of plastic waste generation offer the possibility of increasing the recovery of plastic waste streams in urbanized settings. To quantify the environmental performance of such systems, this study compares the life cycle greenhouse gas emissions of large-scale centralized facilities versus distributed small-scale facilities for sorting and recycling plastic bottles and takeaway containers generated in the central region of Singapore. An agent-based model is used to simulate different scenarios of plastic waste generation, collection routes, sorting, and recycling. The simulation results are used in a multi-level life cycle assessment to quantify the greenhouse gas emissions of the plastic sorting and recycling network as well as its individual entities. The results reveal that the life cycle greenhouse gas emissions of small-scale distributed plastic recycling compared to large-scale centralized systems are sensitive to the transport distance traveled and the type of trucks used. © 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/3.0/ ). Peer-review under responsibility of the scientific committee of the 27th CIRP Life Cycle Engineering (LCE) Conference.

A Green COVID-19 Recovery of the EU Basic Materials Sector: Identifying Potentials, Barriers and Policy Solutions

This paper explores which climate-friendly projects could be part of the COVID-19 recovery while jump-starting the transition of the European basic materials industry. Findings from a literature review on technology options in advanced development stages for climate-friendly production and enhanced sorting and recycling of steel, cement, aluminium and plastics are combined with insights from interviews with 31 European industry stakeholders about the practical and economic feasibility of these technology options. Results indicate that with an estimated investment of 28.9 billion Euro, about 20% of EU’s basic materials could be produced through low-emission processes or additional recycling by 2025 with technologies that are commercially available or at pilot scale today. However, our stakeholder consultation also shows that in order to make these short-term investments viable in the long term, six main barriers need to be addressed, namely i) the lack of effective and predictable carbon pricing, ii) the limited availability of affordable green electricity, iii) the lack of a regulatory framework for circularity, iv) low technology readiness and funding, v) the lack of infrastructure for hydrogen, CO2 and power, and vi) the lack of demand for climate-friendly and recycled materials. Based on these insights, the paper proposes elements of a policy package that can create a long-term framework favourable for investments in these technologies and should ideally accompany the recovery package to give credibility to investors that the business case will last beyond the recovery timeframe.

PRODUCTION AND CHARACTERISATION OF SRF PREMIUM QUALITY FROM MUNICIPAL AND COMMERCIAL SOLID NON-HAZARDOUS WASTES IN AUSTRIA, CROATIA, SLOVENIA AND SLOVAKIA

The production of Solid Recovered Fuel (SRF) and related energy recovery in the European cement industry represents the state of the art in waste management, having evolved into a highly important part of a sustainable and circular economy. This paper describes the production and quality of eight Solid Recovered Fuels (SRF) of PREMIUM quality that are produced from Municipal (Mixed) and selected Commercial Wastes (i.e. Bulky and Lightweight Fraction from Plastic Sorting Plants) in three types of treatment plants located in four European countries, namely Austria, Croatia, Slovenia and Slovakia. The investigated SRF PREMIUM Quality was produced in three different Plant Types applying various process technologies. All three types have been investigated and are described in detail (i.e. flow sheet). Eight SRF PREMIUM Qualities have been comprehensively investigated by sorting, sieving, and physical-chemical analyses. Analyses performed are in accordance with (inter)national standards (i.e. Austrian “ÖNORM”, European “EN” standards and CEN TC 343 guidelines). The results gained show that all investigated SRF fulfil the Austrian quality requirements for heavy metals before co-incineration in the cement industry and it can be confirmed that SRF produced in the investigated plants in Austria, Croatia, Slovenia and Slovakia in fact may be declared as “SRF PREMIUM Quality” that can be used for energy recovery on the European SRF market and utilized in the European cement industry.

An Innovative Route to Circular Rigid Plastics

An innovative route for plastics recycling is proposed, based on a combination of a logarithmic sorting process and colour plus high-resolution near-infrared (NIR) sensors. Although counterintuitive, it is shown that such a technology could sort clean flakes from rigid packaging waste into a very large number of different plastic grades with modest sorter capacity, provided that the chosen sensor is able to differentiate correctly between any two grades of plastics in the waste. Tests with high-resolution NIR on single pixels of transparent flakes from different types and brands of packaging show that this is indeed the case for a selection of 20 different packaging items bought from shops. Moreover, the results seem to indicate, in line with previous research, that high-resolution NIR data can be linked to important physical plastic properties like the melt flow viscosity and tensile strength. The attraction of deep sorting of waste plastics with relatively cheap sensors and modest sorter capacity is that the present industrial practice of tuning plastic grades to specific applications could coexist with commercial high-grade recycling at high levels of circularity and low carbon footprint. Therefore, advanced recycling technology is likely to be a societal alternative to phasing out plastics for rigid applications.

MIR spectral characterization of plastic to enable discrimination in an industrial recycling context: II. Specific case of polyolefins

Sorting at industrial scale is required to perform mechanical recycling of plastics in order to obtain properties that could be competitive with virgin polymers. As a matter of fact, the most part of the various types of plastic waste are not miscible and even compatible. Mid-Infrared (MIR) HyperSpectral Imagery (HSI) is viewed as one of the solutions to the problem of black plastic sorting. Many Waste of Electrical and Electronic Equipment (WEEE) plastics are black. Nowadays, these materials are difficult to sort at an industrial scale because the main used pigment to produce this color, carbon black, masks the Near-Infrared (NIR) spectra of polymers, the currently most used technology for acute sorting in industrial conditions.In this study, laboratory Fourier-Transform Infrared (FTIR) in Attenuated Total Reflection mode (ATR) has been used as a theoretical toolbox based on physical chemistry to help building an automated HSI discrimination despite its limited conditions, especially shorter wavelengths ranges. Weaker resolution and very short acquisition times are other HSI limitations. Helping fast and exhaustive laboratory characterizations of polymeric waste stocks is the other goal of this study. This study focusses on polyolefins as they represent the second biggest fraction of WEEE plastics (WEEP) after styrenics and since little quantities mixed to styrenics during mechanical recycling can lead to important decrease in mechanical properties. Twelve references were thus evaluated and compared between each other and with real waste samples to highlight spectral elements, which can enable differentiation. Charts compiling the signals of discussed polymers were built aiming to the same objective.

Closing the loop for PET, PE and PP waste from households: Influence of material properties and product design for plastic recycling

Recycling of plastic is an important step towards circular economy. However, plastic from household waste (HHW) is a heterogeneous and contaminated resource, leading to recycled plastic with reduced quality, limiting the potential for closed-loop recycling. In addition to regulatory requirements for the chemical composition of recycled plastic, reduced physical and mechanical properties may limit the potential for closed-loop recycling. Consequently, this study analyses the thermal degradation, processability and mechanical properties of a range of reprocessed PET, PE and PP samples from source-separated plastic in HHW. On this basis, the potential for closed-loop recycling is evaluated. The study demonstrated that PET, PE and PP recycling represent different challenges. Potential degradation of the PET polymer can be reversed in a decontamination process, making PET waste well-suited for closed-loop, multiple times recycling, even when the degree of heterogeneity in the waste is high. The processability of different kinds of PE and PP packaging types varied considerably, especially for PP. Consequently, current recycling of mixed PP waste and even separate recycling of individual PP waste packaging types, will not technically facilitate recycling into new packaging products. This highlights the importance of PE and PP waste homogeneity when sent to reprocessing. Such homogeneity may be achieved through additional plastic sorting and regulatory harmonisation of product design, accounting for polymer properties and recyclability. Degradation of PP during recycling was shown to be substantial, representing another important limitation for PP recycling, necessary to address in the future.

Influence of surface roughness and surface moisture of plastics on sensor-based sorting in the near infrared range.

In the project 'NEW-MINE' the use of sensor-based sorting machinery in the field of 'landfill mining' is investigated. Defilements pose a particular challenge in the treatment and sorting of plastics contained in landfills. For this reason, the effects of various pollutants caused by the interactions in the landfill body or the mechanical treatment steps in landfill mining are examined. In the following elaboration, the focus is on the influences of surface moisture and surface roughness of plastics on sensor-based sorting by means of near-infrared technology. Near-infrared radiation (NIR) in a wavelength range of 990 nm to 1500 nm has been used for the detection and classification of plastic particles. The experiments demonstrate that increased surface roughness reduces signal noise and thereby improves the classification of both spectrally similar and transparent plastics, but reduces the yield of low-softening plastics because their sliding speed on a sensor-based chute sorter varies as a result of the heating of the chute. Surface moisture causes the absorption of radiation from 1115 nm (high density polyethylene [HDPE], linear low density polyethylene [LLDPE], polyethylen terephthalate [PET] and polyvinylchloride [PVC]) or from 1230 nm (low density polyethylene [LDPE], polypropylene [PP] and thermoplastic polyurethane [TPU]) up to at least 1680 nm, which causes amplification or attenuation of various extremes in the derivative. However, the influence of surface moisture on the yield of plastics is usually very low and depends on the spectral differences between the different plastics.

Performance Evaluation of a Time-Gated Fluorescence Spectroscopy Measurement System for the Classification and Recycling of Plastics.

Plastics have many unrivaled properties and are thus indispensable materials with an ever-increasing production. Since the plastics recycling rates are still small, the plastic waste that ends up on landfills, in the environment including oceans, and incineration plants also steadily grows. Large-scale automated sorting of waste plastics may help solve the problem. However, most state-of-the-art approaches are limited to a (very) small number of plastic types that can be simultaneously sorted and have severe difficulties with black plastics. The labeling of plastics with fluorescent tracers ("markers") during their production has the potential to enable the fast and highly reliable classification and automated sorting of many different plastic types simultaneously. Unfortunately, the unique marker fluorescence ("optical fingerprint") might be obscured by the autofluorescence (AF) often emitted by plastics. Recently, we have shown that time-gated fluorescence spectroscopy (TGFS) can be successfully applied to eliminate the influences from AF. In this study, we present the prototype of a TGFS measurement system for the classification and sorting of plastics and evaluate its performance in a typical industrial situation. With 150 000 investigated plastics flakes from 10 different plastic types that were labeled with binary combinations of six fluorescent markers, an overall plastics recovery rate (mean true positive rate ) of 99.76%, and a plastics purity (positive predictive value ) of 99.88% were achieved. Additional simulations that were carried out based upon the experiments allow a prediction of the performance as a function of the signal-to-noise (S/N) ratio such that various system parameters can be adapted to the particular situation.

Strategies for managing plastic waste from construction and manufacturing projects

Plastics are inexpensive, lightweight and durable materials, which can readily be moulded into a variety of products that find use in a wide range of applications. Consequently, the production of plastics has increased markedly over the last 60 years. However, current levels of their usage and disposal generate several environmental problems. Plastics consume approximately 8% of world oil production: 4% as raw material for plastics and 3% to 4% as energy for manufacture. A major portion of plastic produced each year is used to make disposable items of packaging or other short-lived products that are discarded within a year of manufacture. These observations indicate that our current use of plastics is not sustainable. In addition, because of the durability of the polymers involved, substantial quantities of discarded end-of-life plastics are accumulating as debris in landfills and in natural habitats worldwide. The manufacturing industry has developed considerably and so has the use of plastics. The growth has come with the challenge of plastic waste disposal which causes pollution. Plastic pollution involves the accumulation of plastic waste products in the environment that adversely affects wildlife, wildlife habitat or humans. Plastic pollution can unfavourably affect lands, waterways and oceans. This is not only evident in the marketplace; it is also evident at the conclusion of most manufacturing projects where the plastic is widely used for packaging and other short-lived products that must be discarded within a year of manufacture. Although efforts have been made to effectively handle the challenge there is still need to improve on the percentage of plastic waste from engineering projects that is recycled. According to Rugwiza (2012), only 1% of manufactures in Kampala have plastic recycling facilities. The paper seeks to present the strategies under consideration in dealing with the problem. Reuse, recycling and reduce of the waste materials has been encouraged for many years; however, it is still not used for many construction site activities. Recycling is one of the most important actions currently available to reduce these impacts and represents one of the most dynamic areas in the plastics industry today. Recycling provides opportunities to reduce oil usage, carbon dioxide emissions and the quantities of waste requiring disposal. Plastic reduction efforts have occurred in some areas in attempts to reduce plastic consumption and pollution and promote plastics recycling. There has been remarkable growth in recycling of plastic materials in the last decade in Uganda. This has been helped by advances in technologies and systems for the collection, sorting and reprocessing of recyclable plastics. This has created opportunities and benefits for the environment as well as the economy. With the combined effort of the manufacturing industry, the public and government, it may be possible to avert the dangers related to plastic waste and divert majority of the plastic waste from landfills to recycling. This will go a long way in ensuring green manufacturing projects with minimal effect to the environment. Keywords: Plastic Waste, Construction, Manufacturing, Sustainability

Feasibility Study on S-Band Microwave Radiation and 3D-Thermal Infrared Imaging Sensor-Aided Recognition of Polymer Materials from End-of-Life Vehicles.

With the increase the worldwide consumption of vehicles, end-of-life vehicles (ELVs) have kept rapidly increasing in the last two decades. Metallic parts and materials of ELVs can be easily reused and recycled, but the automobile shredder residues (ASRs), of which elastomer and plastic materials make up the vast majority, are difficult to recycle. ASRs are classified as hazardous materials in the main industrial countries, and are required to be materially recycled up to 85–95% by mass until 2020. However, there is neither sufficient theoretical nor practical experience for sorting ASR polymers. In this research, we provide a novel method by using S-Band microwave irradiation together with 3D scanning as well as infrared thermal imaging sensors for the recognition and sorting of typical plastics and elastomers from the ASR mixture. In this study, an industrial magnetron array with 2.45 GHz irradiation was utilized as the microwave source. Seven kinds of ELV polymer (PVC, ABS, PP, EPDM, NBR, CR, and SBR) crushed scrap residues were tested. After specific power microwave irradiation for a certain time, the tested polymer materials were heated up to different extents corresponding to their respective sensitivities to microwave irradiation. Due to the variations in polymer chemical structure and additive agents, polymers have different sensitivities to microwave radiation, which leads to differences in temperature rises. The differences of temperature increase were obtained by a thermal infrared sensor, and the position and geometrical features of the tested scraps were acquired by a 3D imaging sensor. With this information, the scrap material could be recognized and then sorted. The results showed that this method was effective when the tested polymer materials were heated up to more than 30 °C. For full recognition of the tested polymer scraps, the minimum temperature variations of 5 °C and 10.5 °C for plastics and elastomers were needed, respectively. The sorting efficiency was independent of particle sizes but depended on the power and time of the microwave irradiation. Generally, more than 75% (mass) of the tested polymer materials could be successfully recognized and sorted under an irradiation power of 3 kW. Plastics were much more insensitive to microwave irradiation than elastomers. With this method, the tested mixture of the plastic group (PVC, ABS, PP) and the mixture of elastomer group (EPDM, NBR, CR, and SBR) could be fully separated with an efficiency of 100%.

USE OF ACRYLONITRILE-BUTADIENE-STYRENE FROM WASTE ELECTRIC AND ELECTRONIC EQUIPMENT WITHOUT AN ACCURATE PREVIOUS SEPARATION

The aim of this work it to develop recycling strategies for Acrylonitrile-Butadiene-Styrene (ABS), coming from plastic WEEE stream, avoiding sorting by type. Self-compatibilization of ABS/HIPS blends, as well as the addition of Styrene-Butadiene-Styrene (SBS) as a compatibilizer to ABS/HIPS blends in order to improve mechanical properties, were studied. In this way, thermal behavior, mechanical performance and morphology of ABS/HIPS physical blends with two different proportions, 80/20 and 50/50, was analyzed comparatively with single ABS to assess self-compatibilization effectiveness. Obtained results indicate that ABS/HIPS self-compatibilization is effective. ABS can tolerate up to 50 wt% of HIPS conserving its properties with a slight improvement in ductility and strength. This allows a wider error in plastic sorting by type within plastic WEEE stream and consequently costs can be reduced. Same blends proportions with the addition of 2 wt% of SBS was also studied in comparison to their physical blends and single ABS. Mechanical properties of SBS-compatibilized blends were notably improved with respect to physical blends and consequently to ABS. Results are very promising for plastic WEEE recycling leading to a sustainable strategy that can promote the reuse of recycled ABS blended with other plastic WEEE instead of single ABS.

Recent Developments in Plastic Sorting Machines Based on Optical Identification

Recent Developments in Plastic Sorting Machines Based on Optical Identification

A discrimination model in waste plastics sorting using NIR hyperspectral imaging system

Classification of plastics is important in the recycling industry. A plastic identification model in the near infrared spectroscopy wavelength range 1000–2500 nm is proposed for the characterization and sorting of waste plastics using acrylonitrile butadiene styrene (ABS), polystyrene (PS), polypropylene (PP), polyethylene (PE), polyethylene terephthalate (PET), and polyvinyl chloride (PVC). The model is built by the feature wavelengths of standard samples applying the principle component analysis (PCA), and the accuracy, property and cross-validation of the model were analyzed. The model just contains a simple equation, center of mass coordinates, and radial distance, with which it is easy to develop classification and sorting software. A hyperspectral imaging system (HIS) with the identification model verified its practical application by using the unknown plastics. Results showed that the identification accuracy of unknown samples is 100%. All results suggested that the discrimination model was potential to an on-line characterization and sorting platform of waste plastics based on HIS.

WEEE plastic sorting for bromine essential to enforce EU regulation

The plastics of waste of electric and electronic equipment (WEEE) are improved for fire safety by flame retardants, and particularly brominated flame retardants (BFR). As waste, the management of these plastic fractions must comply with the update of the regulation of waste hazard classification (2014, 2017), the publication of a technical standard on management of WEEE (2015), and a restriction of use for decabromodiphenylether in the product regulation (2017).Data of bromine (n=4283) and BFR concentrations (n=98) in plastics from electric and electronic equipment (EEE), and from WEEE processing facilities before and after sorting for bromine in four sites in France have been studied for chemical composition and for regulatory classification. The WEEE was analysed by handheld X-ray fluorescence, and the waste was sorted after shredding, by on-line X-ray transmission for total bromine content (< or > 2000 mg/kg) in small household appliances (SHA), cathode ray tubes (CRT) and flat screens plastics.In equipment (n=347), 15% of the equipment items have no bromine, while 46% have at least one part with bromine, and 39% have all parts brominated. The bromine concentration in plastics is very heterogeneous, found in high concentrations in large household appliance (LHA) plastics, and also found in unexpected product categories, as observed by other authors. Clearly, an unwanted global loop of brominated substances occurs via the international recycling of plastic scrap.In waste (n=65), polybromobiphenyls, polybromodiphenylethers (PBDE), tetrabromobisphenol A (TBBPA) and hexabromocyclododecane were analysed. The most concentrated BFRs are decaBDE (3000 mg/kg) and TBBPA (8000 mg/kg). The bromine concentration of regulated brominated substances was identified in 2014 and 2015 to be up to 86% of total bromine in “old” waste (SHA, CRT), 30–50% in “younger” waste (Flat screens), and a mean of only 8% in recent products (2009–2013). Regulated substances are a minority of all the brominated substances and the only practical way to sort is to measure total bromine on-line. The sorting reduces the mean bromine concentration in the “Low Br” fraction in all sites, and reduces the decaBDE concentration to levels below the restricted use limit. After sorting, the concentration in the “High Br” fractions exceeds all present or future regulatory limits.In conclusion, sorting of small household appliances, cathode ray tubes and flat screen plastics is necessary to avoid uncontrolled dispersion of regulated substances in recycled raw material. Other categories (large household appliances, electric and electronic tools, lighting equipment) should also be considered, since their total bromine content (unweighted mean concentration) is high for some of these products. A European campaign consisting of 7 countries and 35 sites will begin in 2017, directed by WEEE Forum, the European association speaking for thirty-one not-for-profit e-waste producer responsibility organisations, to assess the mean bromine content of plastics from large household appliances after shredding.

Is two better than one? Muscle vibration plus robotic rehabilitation to improve upper limb spasticity and function: A pilot randomized controlled trial.

Even though robotic rehabilitation is very useful to improve motor function, there is no conclusive evidence on its role in reducing post-stroke spasticity. Focal muscle vibration (MV) is instead very useful to reduce segmental spasticity, with a consequent positive effect on motor function. Therefore, it could be possible to strengthen the effects of robotic rehabilitation by coupling MV. To this end, we designed a pilot randomized controlled trial (Clinical Trial NCT03110718) that included twenty patients suffering from unilateral post-stroke upper limb spasticity. Patients underwent 40 daily sessions of Armeo-Power training (1 hour/session, 5 sessions/week, for 8 weeks) with or without spastic antagonist MV. They were randomized into two groups of 10 individuals, which received (group-A) or not (group-B) MV. The intensity of MV, represented by the peak acceleration (a-peak), was calculated by the formula (2πf)2A, where f is the frequency of MV and A is the amplitude. Modified Ashworth Scale (MAS), short intracortical inhibition (SICI), and Hmax/Mmax ratio (HMR) were the primary outcomes measured before and after (immediately and 4 weeks later) the end of the treatment. In all patients of group-A, we observed a greater reduction of MAS (p = 0.007, d = 0.6) and HMR (p<0.001, d = 0.7), and a more evident increase of SICI (p<0.001, d = 0.7) up to 4 weeks after the end of the treatment, as compared to group-B. Likewise, group-A showed a greater function outcome of upper limb (Functional Independence Measure p = 0.1, d = 0.7; Fugl-Meyer Assessment of the Upper Extremity p = 0.007, d = 0.4) up to 4 weeks after the end of the treatment. A significant correlation was found between the degree of MAS reduction and SICI increase in the agonist spastic muscles (p = 0.004). Our data show that this combined rehabilitative approach could be a promising option in improving upper limb spasticity and motor function. We could hypothesize that the greater rehabilitative outcome improvement may depend on a reshape of corticospinal plasticity induced by a sort of associative plasticity between Armeo-Power and MV.

Modified tribo-charging device for the electrostatic separation of plastics from granular industrial wastes

ABSTRACTTribo-electrostatic separation is the solution of choice for the selective sorting of various plastics contained in a granular mixture. This work is aimed at validating the efficiency of a modified compressed-air-operated tribo-charging device for the electrostatic separation of mixed granular plastics originating from industrial waste. The experiments are carried out with a mixture of mm-size orange and beige PVC granules, using a free-fall electrostatic separator. At optimum operating conditions, 93% of the orange PVC and 96% of the beige PVC were recovered at purities higher than, respectively, 99% and 95%. The numerical simulation of charged particles trajectories facilitates the interpretation of the experimental results and the analysis of the factors that affect the efficiency of the separation process: high-voltage level, configuration of the electrodes system, and position of the feeding unit.