Processability of Different Polymer Fractions Recovered from Mixed Wastes and Determination of Material Properties for Recycling.

To achieve future recycling targets and CO2 and waste reduction, the transfer of plastic contained in mixed waste from thermal recovery to mechanical recycling is a promising option. This requires extensive knowledge of the necessary processing depth of mixed wastes to enrich plastics and their processability in polymer processing machines. Also, the selection of a suitable processing method and product application area requires appropriate material behaviour. This paper investigates these aspects for a commercial processed, mixed waste, and two different mixed polyolefin fractions. The wastes are processed at different depths (e.g., washed/not washed, sorted into polyethylene, polypropylene, polyethylene terephthalate, polystyrene/unsorted) and then either homogenised in the extruder in advance or processed heterogeneously in the compression moulding process into plates. The produced recyclates in plate form are then subjected to mechanical, thermal, and rheological characterisation. Most investigated materials could be processed with simple compression moulding. The results show that an upstream washing process improves the achievable material properties, but homogenisation does not necessarily lead to an improvement. It was also found that a higher treatment depth (recovery of plastic types) is not necessary. The investigations show that plastic waste recovery with simple treatment from mixed, contaminated wastes into at least downcycling products is possible.

Behaviors Associated with Internet Use in Military Medical Students and Residents.

INTRODUCTION: Problematic use of video games, social media, and Internet-related activities may be associated with sleep deprivation and poor work performance. The Internet Addiction Test was given to military medical and nursing students and housestaff to assess problematic Internet use. METHODS: Medical and nursing students at the Uniformed Services University of the Health Sciences and residents from Naval Medical Center San Diego were contacted via email (n = 1,000) and given a survey that included the Internet Addiction Test (IAT) and questions asking about other specific lifestyle variables. Individuals who received an Internet Addiction Score (IAS) ≥50 were identified as likely experiencing harmful effects of Internet addiction (IA). RESULTS: Of 399 surveys submitted, 68 were omitted due to gross incompletion or failing to finish the entirety of the IAT. Of the participants included, 205 (61.1%) were male and 125 (37.9%) were female. The mean age was 28.6 years old (S.D. = 5.1 years). In regards to training status, completed surveys were assessed for 94 medical residents, 221 School of Medicine students, and 16 Graduate School of Nursing students. Our survey showed 5.5% of the participants (n = 18) indicated problems with Internet use that are concerning for IA. CONCLUSIONS: The study results indicated that our population showed problematic Internet use in the lower range of global estimates of IA. Rates of IA further decreased between medical students and residents. Multiple lifestyle variables were significantly associated with IA score and may serve as indicators of a higher score. Interestingly, the use of social media during sleeping hours was most significantly associated with increased IAS. This paper discusses IA among military medical and nursing trainees and how problematic Internet use may affect work performance and force readiness.

Towards an assistance strategy that reduces unnecessary collision alarms: An examination of the driver's perceived need for assistance.

The activation of present-day collision avoidance systems mainly depends on the time to collision (TTC) criterion. Such a warning strategy that is based on kinematic criteria alone often yields warning signals that drivers perceive to be unnecessary. To increase system effectiveness and user acceptance, the reduction of alert rates by tailoring system activation to drivers' needs is of great interest. The present driving simulator study investigated if drivers' perceived need for assistance in potential collision situations is primarily predicted by the TTC or by drivers' subjective hazard perception that was assumed to be influenced by the current maneuver intention. Thirty participants encountered traffic scenarios with varying levels of TTC. Each scenario was experienced with 2 different maneuver intentions to manipulate the relevance of the potential hazard. A multilevel moderated mediation analysis revealed that drivers' subjective hazard perception mediated the relationship between the TTC-based crash likelihood and drivers' perceived need for assistance. Additionally, the mediated relationship was significantly stronger when the hazard interfered with the intended maneuver. These results suggest that to appropriately adapt driver assistance to drivers' perceived needs, a warning strategy is required that considers TTC as well as drivers' maneuver intentions. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Effects of Non-Driving Related Task Modalities on Takeover Performance in Highly Automated Driving.

OBJECTIVE: Aim of the study was to evaluate the impact of different non-driving related tasks (NDR tasks) on takeover performance in highly automated driving. BACKGROUND: During highly automated driving, it is allowed to engage in NDR tasks temporarily. However, drivers must be able to take over control when reaching a system limit. There is evidence that the type of NDR task has an impact on takeover performance, but little is known about the specific task characteristics that account for performance decrements. METHOD: Thirty participants drove in a simulator using a highly automated driving system. Each participant faced five critical takeover situations. Based on assumptions of Wickens's multiple resource theory, stimulus and response modalities of a prototypical NDR task were systematically manipulated. Additionally, in one experimental group, the task was locked out simultaneously with the takeover request. RESULTS: Task modalities had significant effects on several measures of takeover performance. A visual-manual texting task degraded performance the most, particularly when performed handheld. In contrast, takeover performance with an auditory-vocal task was comparable to a baseline without any task. Task lockout was associated with faster hands-on-wheel times but not altered brake response times. CONCLUSION: Results showed that NDR task modalities are relevant factors for takeover performance. An NDR task lockout was highly accepted by the drivers and showed moderate benefits for the first takeover reaction. APPLICATION: Knowledge about the impact of NDR task characteristics is an enabler for adaptive takeover concepts. In addition, it might help regulators to make decisions on allowed NDR tasks during automated driving.

Speciation and mobility of arsenic in agricultural lime.

Agricultural liming materials are used to correct soil acidity and to improve plant growth and microbial functionality. A relatively low-grade agricultural lime was found to contain up to 125 mg kg(-1) arsenic (As), which is above any fertilizing materials code threshold. The color of the milled material is brown due to ample oxide dendrites. Microprobe elemental maps confirmed that these accessory oxide mineral phases are responsible for the elevated As concentrations in the limestone. The black Mn-bearing dendrites contain minor amounts of As, whereas the brown Fe-bearing dendrites contain the major part of the As inventory, with an Fe/As molar ratio around 100. Because the elemental maps represent only a few sample regions of interest (ROI), the results are corroborated by a bulk five-step sequential extraction of the lime, which suggests that a majority of the As is bound to acid-reducible phases. Because repartitioning of the As oxyanion during extraction cannot be ruled out, X-ray absorption spectroscopy with micrometer resolution (micro-XAS) was used as a solid-state speciation analysis approach. The micro-XAS results at the Fe K-edge for the selected ROIs revealed the brown dendrites to consist of ferrihydrite and goethite, whereas those at the As K-edge revealed that the pentavalent As species arsenate predominates, with As-Fe distance and coordination indicating binding as a mononuclear inner-spheric adsorbate complex. Batch experiments with soil exposed to submerged conditions of up to 41 d revealed a negligible As release rate from the lime (approximately 40 ng kg(-1) d(-1)). The results of this study corroborate regulatory codes that set the permissible As content in agricultural lime relative to the respective Fe content.

Adsorption mechanism of arsenate by zirconyl-functionalized activated carbon.

Arsenate [As(V)] and arsenite [As(III)] sorption at the solid-water interface of activated carbon impregnated with zirconyl nitrate (Zr-AC) was investigated using X-ray absorption spectroscopy (XAS) and surface complexation modeling. The XAS data at the Zr K-edge suggest that the structure of the zirconyl nitrate coating is built from chains of edge-sharing ZrO8 trigonal dodecahedra bound to each other through two double hydroxyl bridges. The 8-fold coordination of each Zr atom is completed by four O atoms, which share a bit less than the two theoretically possible bidentate nitrate groups. On impregnation, two of the O atoms may lose their nitrate group and be transformed to hydroxyl groups ready for binding to carboxylic or phenolic ligands at the AC surface. As K-edge XANES results showed the presence of only As(V) on adsorption regardless of the initial As oxidation state. Oxidation to As(V) is probably mediated by available carbon species on the AC surface as found by batch titration. Zr K-edge EXAFS data indicate that arsenate tetrahedra form monodentate mononuclear surface complexes with free hydroxyl groups of zirconyl dodecahedra, whereby each bidentate nitrate group is exchanged by up to two arsenate groups. The inner-sphere arsenate binding to the Zr-AC surface sites constrained with the spectroscopic results was used in the formulation of a surface complexation model to successfully describe the adsorption behavior of arsenate in the pH range between 4 and 12. The results suggest therefore that Zr-AC is an effective adsorbent for arsenic removal due to its high surface area and the presence of high affinity surface hydroxyl groups.

Spironoura tikasinghi sp. n. (nematoda: kathlanidae) from a turtle in Trinidad, W.I

Spironura tikasinghi sp. n. from the cecum and small intestine of a turtle, Geoemyda punctularia, from Trinidad, is characterized by having spicules 530 to 570 um, and a gubernaculum 310 to 340 um long. It is compared with other species from South and Central America, and with those reported from turtles. (AU)