Step Time Research Articles

The contribution of walking speed versus recent stroke to temporospatial gait variability

BackgroundInconsistent results have been reported for temporospatial gait variability after stroke. Given the large differences in gait speed across stroke subjects and relative to healthy controls, it is not clear which changes in temporospatial gait variability can be ascribed to the walking speed during gait evaluation versus the consequences of stroke. Research questionsDoes temporospatial gait variability differ between (1) stroke subjects grouped in clinically-relevant functional ambulation classes, (2) the paretic and non-paretic legs within each class, and (3) stroke and healthy subjects after controlling for gait speed? MethodsStroke subjects were evaluated at their comfortable speed < 2 months post-onset and classified into the household (<40 cm/s, n = 38), limited-community (40–80 cm/s, n = 35), and full-community (>80 cm/s, n = 14) walkers. Coefficients of variation (CVs) for paretic and non-paretic stance, initial double-support, and single-support times, step length, step cadence, and step width were compared across the stroke ambulation classes and between the two legs. For the parameters with significantly different CVs between stroke subjects and 33 age-matched controls walking at very-slow and free speeds, a 1-way ANCOVA was used with the gait speed as a covariate. ResultsFor most step parameters, CVs were greater in slower stroke ambulation classes except for the smaller step width CV. The differences between the paretic and non-paretic legs emerged in slower walkers only. After controlling for the gait speed, CVs of stroke subjects no longer significantly differed from controls walking at very-slow speed. With controls walking at free speed, however, CVs for the paretic and non-paretic single-support times and the non-paretic step time remained significantly different. SignificanceGait is more variable at slower speeds both in stroke subjects and healthy controls. After accounting for the free gait speed, the increased variability of only a few temporal parameters may be attributed to a recent stroke.

Kinematic Parameters That Can Discriminate in Levels of Functionality in the Six-Minute Walk Test in Patients with Heart Failure with a Preserved Ejection Fraction.

It is a challenge to manage and assess heart failure with preserved left ventricular ejection fraction (HFpEF) patients. Six-Minute Walk Test (6MWT) is used in this clinical population as a functional test. The objective of the study was to assess gait and kinematic parameters in HFpEF patients during the 6MWT with an inertial sensor and to discriminate patients according to their performance in the 6MWT: (1) walk more or less than 300 m, (2) finish or stop the test, (3) women or men and (4) fallen or did not fall in the last year. A cross-sectional study was performed in patients with HFpEF older than 70 years. 6MWT was carried out in a closed corridor larger than 30 m. Two Shimmer3 inertial sensors were used in the chest and lumbar region. Pure kinematic parameters analysed were angular velocity and linear acceleration in the three axes. Using these data, an algorithm calculated gait kinematic parameters: total distance, lap time, gait speed and step and stride variables. Two analyses were done according to the performance. Student’s t-test measured differences between groups and receiver operating characteristic assessed discriminant ability. Seventy patients performed the 6MWT. Step time, step symmetry, stride time and stride symmetry in both analyses showed high AUC values (>0.75). More significant differences in velocity and acceleration in the maximum Y axis or vertical movements. Three pure kinematic parameters obtained good discriminant capacity (AUC > 0.75). The new methodology proved differences in gait and pure kinematic parameters that can distinguish two groups according to the performance in the 6MWT and they had discriminant capacity.

Experimental and molecular dynamic studies of phase transformation and amorphization in silicon during high-energy ball milling

Nano-sized and amorphous silicon (α-Si) have a wide range of properties and applications, but their atomistic structure and the process of crystal evolution are still unclear. In this study, a combined action is used to present a mechanism for the crystal-to-amorphous solid–solid phase transition in silicon during mechanical alloying (MA) at room temperature. For this purpose, the ball milling of silicon was performed and changes in crystallographic structure and amorphous phase were studied by scanning electron microscopy (SEM), X-ray diffraction patterns (XRD), and energy dispersive X-ray spectroscopy (EDX). The process of changing phase was determined by quantitative phase analysis (MAUD/Rietveld refinement). In the simulation part, a crystal structure of silicon consisting of 64 atoms was created and uniaxial and biaxial external pressures were applied randomly by BIOVIA Materials Studio. The time step and simulation time were 1 and 300 Ps, respectively. Important atomic properties including density, mean square displacement (MSD), angle length and bonds distribution, and the fraction of broken bands were measured after applying per compression. Atomic structure and changes in crystalline phase to nano and amorphous phases were studied and these results had a considerable agreement with the experimental part and well-known previous studies. The diamond cubic structure shows a remarkable toughness during the modeling and so amorphization was performed at an exponential evolution. The Results of the simulations showed that the bond angle and length distribution and MSD, were increased significantly, and in contrast, density was decreased to 1.254 g/cm3. The percentage of the broken Si-Si bonds was 58.12 % and a new definition of Si amorphization based on the fraction of covalent bonds was proposed. The amorphization started from the surface of Si and spread by the partial distribution toward the crystal structure. These findings show that the proposed mechanism based on the fraction of breaking bonds and pressure-induced amorphization could be used for the accurate simulation of the solid–solid phase transformation.

No Influence of Mechatronic Poles on the Movement Pattern of Professional Nordic Walkers.

This study compared selected temporal and kinematic parameters of normal gait and Nordic Walking (NW) performed with classic and mechatronic poles (classic poles equipped with sensors). It was assumed that equipping NW poles with sensors for biomechanical gait analysis would not impair the NW walking technique. Six professional NW instructors and athletes, including three women, participated in the study. The MyoMotion MR3 motion analysis system was used to collect gait kinematic variables. The subject's task was to cover a 100-m distance with three types of gait: a gait without poles, a gait with classic NW poles, and a gait with mechatronic poles at the preferred speed. Parameters were measured both on the right and left sides of the body. No significant differences were found between gait types for three temporal parameters: step cadence, step, and stride time. For the other variables, all the differences identified were between free-walking and walking with poles, with no differences between standard and mechatronic poles. For nine kinematic parameters, differences between free-walking and walking with poles for both the left and right sides were found, while no differences were due to the pole type. All temporal parameters were characterized by symmetry, while among kinematic parameters, only two were asymmetrical (shoulder abduction-adduction in walking with regular poles and elbow flexion-extension in walking without poles). Equipping classic NW poles with additional signaling and measuring devices (mechatronic poles) does not impair the NW technique, making it possible to use them in further studies of gait biomechanics.

Cognitive parameters can predict change of walking performance in advanced Parkinson's disease - Chances and limits of early rehabilitation.

Links between cognition and walking performance in patients with Parkinson's disease (PD), which both decline with disease progression, are well known. There is lack of knowledge regarding the predictive value of cognition for changes in walking performance after individualized therapy. The aim of this study is to identify relevant predictive cognitive and affective parameters, measurable in daily clinical routines, for change in quantitative walking performance after early geriatric rehabilitation. Forty-seven acutely hospitalized patients with advanced PD were assessed at baseline (T1) and at the end (T2) of a 2-week early rehabilitative geriatric complex treatment (ERGCT). Global cognitive performance (Montreal Cognitive Assessment, MoCA), EF and divided attention (Trail Making Test B minus A, delta TMT), depressive symptoms, and fear of falling were assessed at T1. Change in walking performance was determined by the difference in quantitative walking parameters extracted from a sensor-based movement analysis over 20 m straight walking in single (ST, fast and normal pace) and dual task (DT, with secondary cognitive, respectively, motor task) conditions between T1 and T2. Bayesian regression (using Bayes Factor BF10) and multiple linear regression models were used to determine the association of non-motor characteristics for change in walking performance. Under ST, there was moderate evidence (BF10 = 7.8, respectively, BF10 = 4.4) that lower performance in the ∆TMT at baseline is associated with lower reduction of step time asymmetry after treatment (R 2 adj = 0.26, p ≤ 0.008, respectively, R 2 adj = 0.18, p ≤ 0.009). Under DT walking-cognitive, there was strong evidence (BF10 = 29.9, respectively, BF10 = 27.9) that lower performance in the ∆TMT is associated with more reduced stride time and double limb support (R 2 adj = 0.62, p ≤ 0.002, respectively, R 2 adj = 0.51, p ≤ 0.009). There was moderate evidence (BF10 = 5.1) that a higher MoCA total score was associated with increased gait speed after treatment (R 2 adj = 0.30, p ≤ 0.02). Our results indicate that the effect of ERGT on change in walking performance is limited for patients with deficits in EF and divided attention. However, these patients also seem to walk more cautiously after treatment in walking situations with additional cognitive demand. Therefore, future development of individualized treatment algorithms is required, which address individual needs of these vulnerable patients.

Hallway Gait Monitoring System Using an In-Package Integrated Dielectric Lens Paired with a mm-Wave Radar.

This paper presents a novel hallway gait extraction system that enables an individual's spatiotemporal gait parameter extraction at each gait cycle using a single FMCW (Frequency Modulated Continuous Wave) radar. The purpose of the proposed system is to detect changes in gait that may be the signs of changes in mobility, cognition, and frailty, particularly for older adults in retirement homes. We believe that one of the straightforward applications for gait monitoring using radars is in corridors and hallways, which are commonly available in most retirement and long-term care homes. To achieve in-corridor coverage, we designed an in-package hyperbola-based lens antenna integrated with a radar module package empowered by our fast and easy-to-implement gait extraction method. We validated system functionality by capturing spatiotemporal gait values (e.g., speed, step points, step time, step length, and step count) of people walking in a hallway. The results achieved in this work pave the way to explore the use of stand-alone radar-based sensors in long hallways in retirement apartment buildings or individual's homes for use in day-to-day long-term monitoring of gait parameters of older adults.

ASSOCIATIONS OF GAIT CHARACTERISTICS AND VARIABILITY WITH WALKING EFFICIENCY IN OLDER ADULTS

Abstract Higher energetic cost of walking per unit distance has been linked to many adverse health outcomes in older adults. Aging-related changes in gait characteristics have been postulated to contribute to energetic inefficiency, but previous studies focused on younger adults, and/or examined only a few gait characteristics. In the Baltimore Longitudinal Study of Aging, 507 older adults ≥50 years (72.3±9.8 years, 48.3% women, 48.3% black) without stroke and Parkinson disease had concurrent measurements of usual-paced gait characteristics using 3D motion analysis and energetic cost of walking using indirect calorimetry during a 2.5-min usual-paced overground walk. We tested the associations of the mean and the coefficient of variance (CV) of cadence (steps/min), swing time (ms), double support time (ms), stance time (ms), step time (ms), step length (cm), and step width (cm) with energetic cost of walking using linear regression models, adjusting for demographics, body composition, comorbidities, and gait speed. We found that a 5-cm shorter step length was associated with 0.40 ml/kg/100m higher cost of walking (p&amp;lt; 0.001). A 1% higher CV in swing time and 1% lower CV in step width was associated with 0.152 ml/kg/100m higher (p=0.044) and 0.023 ml/kg/100m lower (p=0.022) cost of walking, respectively. Our results suggest that mean step length and variability in swing time and step width could potentially contribute to the rising cost of walking in older adults. Future longitudinal studies are needed to understand whether changes in gait variability can predict increased energetic cost of walking and can be intervened to preserve energy efficiency.

ASSOCIATION OF COGNITION AND SMARTPHONE SURVEY ATTRIBUTES IN THE ELECTRONIC FRAMINGHAM HEART STUDY

Abstract Mobile technology offers a remote method to monitor health in older adults and it may provide a platform for early detection of cognitive decline. We aimed to examine attributes of smartphone survey use in the electronic Framingham Heart Study (eFHS) cohort in relation to cognitive testing performed at the time of enrollment. eFHS participants who returned smartphone surveys and underwent cognitive testing were considered in the study (n=1810). The CERAD recall score, Victoria Stroop test interference score, and dichotomous AD8 and MOCA (MOCA score ≤ 19, AD8 score ≥2) were considered as primary exposures. App-based survey adherence was defined as a dichotomous outcome based on whether at least one survey was completed at each 3-month period from baseline to 12 months. Several time attributes were considered including survey return time, touch time, step time, and question completion time. Linear mixed models (LMM for time attributes outcomes and generalized LMM for adherence outcome) were fitted for each cognitive score as the predictor adjusting for age, sex, race/ethnicity, and education level. Results suggest that higher CERAD recall scores were associated with higher odds of completing surveys. There was a significant association between all cognitive exposures and survey time attributes. Participants with poorer cognitive function (lower CERAD, higher stroop interference, MOCA score ≤ 19, AD8 score ≥2) had delayed survey return times, higher touch time, higher step time and higher question completion time. This study contributes to the growing body of evidence that smartphones may be an important tool to identify cognitive decline.

ASSOCIATIONS BETWEEN POSTURAL SWAY AND GAIT DOMAINS DURING WALKING WHILE TALKING

Abstract Poor gait performance during walking-while-talking (WWT) is associated with an increased falls risk. Whether this association between WWT and falls is moderated by balance is not known. To address this, we examined 1) cross-sectional associations between postural sway and gait domains during WWT and, 2) whether postural sway moderated the effects of gait domains on falls. Gait (using a computerized walkway) and postural sway in anteroposterior (AP) and mediolateral (ML) directions (using the SwayStar™ system) during WWT were assessed in 357 community-dwelling older adults (M Age 77.9 years; 55.5% female). Principal component analysis was used to derive distinct gait domains: pace (speed, step length), rhythm (swing, stance, step time) and variability (step length variability, double support time variability). Falls incidence over 12 months were ascertained using bi-monthly calls. Multiple linear regression (adjusted for age, sex, and education) was used to examine the associations between postural sway and gait domains. Poisson regression was used to examine the associations of number of falls with gait domains and postural sway. Greater AP- and ML-sway were associated with slower pace, greater rhythm, and greater variability (p&amp;lt; 0.005). Slower pace (not rhythm or variability) was associated with falls incidence (n=95) and the effect of pace on falls (although p&amp;gt;0.005) was reduced by the ML-sway (β for interaction between pace and sway -0.001 95%CI -0.002, 0.0001). These findings suggest that greater sway during WWT is associated with poorer gait performance. Interventions to maintain ML-sway during WWT may assist with reducing the effects of pace on falls risk.

Intensified bio-oil steam reforming for high-purity hydrogen production: Numerical simulation and sorption kinetics

This work proposes the production of high-purity hydrogen by an intensified non-isothermal sorption-enhanced bio-oil steam reforming (SEBOSR) process, by combining the bio-oil steam reforming over a Ni/La2O3-αAl2O3 catalyst and in-situ CO2 adsorption over Li2CuO2. The kinetics of CO2 adsorption on Li2CuO2 was studied experimentally and applied to assess the performance of SEBOSR in a fixed bed reactor via a non-isothermal mathematical model. Model simulations show that the prebreakthrough stage of the SEBOSR process, which corresponds to high purity H2 production, can be extended by increasing the adsorbent loading and the S/C ratio, as well as by decreasing the inlet gas velocity. Increasing inlet temperature generates longer prebreakthrough step times but leads to a reduction in hydrogen purity. This intensified process allows to diminish the catalyst deactivation, which ultimately only occurs in the inlet region of the packed bed to some extent. In addition, SEBOSR indirectly uses sustainable CO2-neutral biomass as a source of hydrogen; highly pure and renewable H2 can be produced in one step (without the need of additional gas purification), via a process with enhanced thermal efficiency.

Walking Step Monitoring with a Millimeter-Wave Radar in Real-Life Environment for Disease and Fall Prevention for the Elderly.

We studied the use of a millimeter-wave frequency-modulated continuous wave radar for gait analysis in a real-life environment, with a focus on the measurement of the step time. A method was developed for the successful extraction of gait patterns for different test cases. The quantitative investigation carried out in a lab corridor showed the excellent reliability of the proposed method for the step time measurement, with an average accuracy of 96%. In addition, a comparison test between the millimeter-wave radar and a continuous-wave radar working at 2.45 GHz was performed, and the results suggest that the millimeter-wave radar is more capable of capturing instantaneous gait features, which enables the timely detection of small gait changes appearing at the early stage of cognitive disorders.

Extraction and Recovery of Metals from Spent HDS Catalysts: Lab- and Pilot-Scale Results of the Overall Process

The present study proposes an overall recycling process for spent hydrodesulfurization (HDS) catalysts. The process put together stages already known in the technical literature, tested again with samples coming from the roasting stage in a pilot kiln, which is the most limiting stage of metal recovery from spent catalysts. These catalysts contain valuable metals like cobalt (Co), molybdenum (Mo), nickel (Ni), and vanadium (V). In particular, one Co-Mo catalyst was treated in order to optimize the roasting step (time, soda ash, and temperature) at a pilot scale and thus maximize the extraction yield of molybdenum (Mo) and vanadium (V). In particular, a dry Co-Mo catalyst was used. After roasting at 700 °C for 2.5 h, the best conditions, the catalysts underwent water leaching, separating Mo and V from Co and the alumina carrier, which remained in the solid residue. The pregnant solution was treated to remove arsenic (As) and phosphorus (P), representing the main impurities for producing steel alloys. V was precipitated as NH4Cl, and further calcined to obtain commercial-grade V2O5, whereas Mo was recovered as molybdic acid by further precipitation at a pH of around one. Thus, molybdic acid was calcined and converted into commercial-grade MoO3 by calcination. The hydrometallurgical section was tested on a lab scale. The total recovery yield was nearly 61% for Mo and 68% for V, respectively, compared with their initial concentration in the spent Co-Mo catalysts.

Toward a theory of ‘stepped-leaders’ in lightning

An unresolved issue in the physics of lightning is an explanation for lightning proceeding to the ground by successive luminous steps separated by ‘dark’ times of many microseconds. There is also no explanation of the structure of the dark column connecting the streamer step with the cloud that can be km in length, is electrically conducting, yet has a very low sustaining electric field. It is proposed that these two processes can be explained by the accumulation of singlet delta metastable oxygen molecules excited in the corona pulses of lightning. The step time is necessary for the excitation of large metastable densities to produce significant metastable detachment of electrons from negative ions. The detached electrons form a highly conducting step, initially luminous, that causes a redistribution of electric fields and an increase in the potential and electric fields at the end of the step to make possible a further step by ionization. These features are supported by calculations of densities of electrons, positive ions, negative ions and singlet delta metastable oxygen molecules for the first 7 μs of a discharge chosen to be initiated by a 50 cm sphere of charged hail particles. The calculated corona streamers produce metastable densities of 1017 cm−3 near the corona source. These metastables, by electron detachment, produce a conducting cylinder 10 m long with a radius of 1 cm and an electron density ∼1012 cm−3 that is attributed to being the first step and a lightning ‘leader’. These conducting regions develop within them very low electric fields. Successive steps are likely to combine to form the long conductive columns of lightning that exist before the return stroke. Electron densities in the leader and the column are an equilibrium between electron production by metastable detachment and electron loss by attachment to neutral oxygen molecules, requiring no electric field.

Gait analysis and avoidance mechanism of pedestrians under the quantitative control of visibility

To investigate the gait characteristics and avoidance mechanism of pedestrians under limited visibilities, a novel method is proposed to realise the quantitative control of visibility conditions. A series of experimental scenarios, including free movement, obstacle avoidance and head-on avoidance, were conducted at various visibility levels. Based on the extracted trajectories, gait parameters, including step width, step length and step time, are measured by using the automatic extraction method. The relations between visibility distance, gait parameters and walking speed are analysed. Furthermore, the obstacle avoidance process, represented by the start point, mid-point and end-point under limited visibilities, is investigated. The minimum distance between two individuals moving in opposite directions is also discussed. Finally, the right-side avoidance preference of individuals is found during the avoidance process. The study is helpful for understanding how humans adjust their movement when confronting different situations in limited visibility environments.

Toward Synthetic Data Generation to Enhance Skidding Detection in Winter Conditions

In this paper, we propose the use of a neural network to identify lateral skidding events of road vehicles used during winter driving conditions. Firstly, data from a simulation model was used to identify the essential vehicle dynamics variables needed and to create the network structure. Then this network was retrained to classify real-world vehicle skidding events. The final network consists of a 3 layer network with 10, 5 and 1 output neurons 13 inputs, 4 outputs and a 5 step time delay. The retrained network was used on a limited set of real vehicle data and confirmed the effectiveness of the network classifying lateral skidding events.

Common fall-risk indicators are not associated with fall prevalence in a high-functioning military population with lower limb trauma.

Persons with lower limb trauma are at high risk for falls. Although there is a wide range of measures used to assess stability and fall-risk that include performance measures, temporal-spatial gait parameters, and nonlinear dynamic stability calculations, these measures are typically derived from fall-prone populations, such as older adults. Thus, it is unclear if these commonly used fall-risk indicators are effective at evaluating fall-risk in a younger, higher-functioning population of Service members with lower limb trauma. Twenty-one Service members with lower limb trauma completed a battery of fall-risk assessments that included performance measures (e.g., four-square-step-test), and gait parameters (e.g., step width, step length, step time) and dynamic stability measures (e.g., local divergence exponents) during 10min of treadmill walking. Participants also reported the number of stumbles and falls over the previous 4weeks. Negative Binomial and Quasibinomial Regressions were used to evaluate the strength of associations between fall-risk indicators and self-reported falls. Participants reported on average stumbling 6(4) times and falling 2(3) times in the previous 4weeks. At least one fall was reported by 62% of the participants. None of the fall-risk indicators were significantly associated with fall prevalence in this population of Service members with lower limb trauma (p>0.1). Despite the high number of reported falls in this young active population, none of the fall-risk indicators investigated effectively captured and quantified the fall-risk. Further research is needed to identify appropriate fall-risk assessments for young, high-functioning individuals with lower limb trauma.

Finding Minimum Production Time and Optimal Procedure for a Project When Step Times are Given by Constructive Real Numbers

In the production process, some jobs can only be done sequentially, while others can be done synchronously. Given the time needed to complete each job, an oriented graph with a source vertex and a sink vertex can be generated. Each route starting from the source vertex and ending at the sink vertex represents a way of completing the project. It is possible to find the minimum production time and the optimal production path when time for each job is given by a rational number. However, this paper proves that there does not exist a computer program that can always generate the minimum time and optimal path when the time needed for each job is a constructive real number.

Safety assessment of the process Duy Tan Plastic Recycling, based on the Starlinger iV+ technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Duy Tan Plastic Recycling (EU register number RECYC264), which uses the Starlinger iV+ technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are dried and crystallised in a first reactor, then extruded into pellets. These pellets are crystallised, preheated and treated in a solid-state polycondensation (SSP) reactor. Having examined the challenge test provided, the Panelconcluded that the drying and crystallisation (step 2), extrusion and crystallisation (step 3) and SSP (step 4) are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these critical steps are temperature, air/PET ratio and residence time for the drying and crystallisation step, and temperature, pressure and residence time for the extrusion and crystallisation step as well as the SSP step. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process rPET Aviv Shalam, based on the Starlinger iV+ technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process rPET Aviv Shalam (EU register number RECYC263), which uses the Starlinger iV+ technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are dried and crystallised in a first reactor, then extruded into pellets. These pellets are crystallised, preheated and treated in a solid-state polycondensation (SSP) reactor. Having examined the challenge test provided, the Panelconcluded that the drying and crystallisation (step 2), extrusion and crystallisation (step 3) and SSP (step 4) are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these critical steps are temperature, air/PET ratio and residence time for the drying and crystallisation step, and temperature, pressure and residence time for the extrusion and crystallisation step, as well as the SSP step. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.

Safety assessment of the process Alef Recycling, based on the Starlinger iV+ technology, used to recycle post-consumer PET into food contact materials.

The EFSA Panelon Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Alef Recycling (EU register number RECYC265), which uses the Starlinger iV+ technology. The input is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes mainly originating from collected post-consumer PET containers, with no more than 5% PET from non-food consumer applications. The flakes are dried and crystallised in a first reactor, then extruded into pellets. These pellets are crystallised, preheated and treated in a solid-state polycondensation (SSP) reactor. Having examined the challenge test provided, the Panelconcluded that the drying and crystallisation (step 2), extrusion and crystallisation (step 3) and SSP (step 4) are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of these critical steps are temperature, air/PET ratio and residence time for the drying and crystallisation step, and temperature, pressure and residence time for the extrusion and crystallisation step as well as the SSP step. It was demonstrated that this recycling process is able to ensure that the level of migration of potential unknown contaminants into food is below the conservatively modelled migration of 0.1μg/kg food. Therefore, the Panelconcluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long-term storage at room temperature, with or without hotfill. The final articles made of this recycled PET are not intended to be used in microwave and conventional ovens and such uses are not covered by this evaluation.