Synthesis and characterisation of potassium polytitanate for photocatalytic degradation of crystal violet

Potassium titanate nanostructures were synthesised by hydrothermal treatment of TiO2 （P25） in KOH and H2O2. As-produced powders were characterised by scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, X-ray diffraction, and nitrogen adsorption-desorption methods. Longitudinally-oriented-wire-like structures with a length up to several micrometres and diameters ranging from 10 to 30 nm were obtained. Larger size fibrous nanowires resulting from the hydrotherrnal treatment showed high affinity in adsorbing crystal violet （CV）, which was mainly due to their high surface area. The photocatalytic bleaching of CV solution revealed that the wires are photoactive under ultraviolet light irradiation. Macroporous nanowires are considered as effective adsorbents of CV, capable of photocatalvtic degradation, and they can be easily separated from the solution by settling.     

Effects of Electron-Beam Irradiation and Ultraviolet Light (365 nm) on Polylactic Acid Plastic Films

Strips of Ca-I [polylactic acid (PLA) monolayer plastic films from Cargill Dow Polymers LLC, Minnetonka, MN] cut in the machine and nonmachine directions were irradiated with an electron beam using a CIRCLE III Linear Accelerator (MeV Industries S.A., Jouy-en-Josas, Cedex, France). The effects of 33-kGy irradiation on the physical properties of the Ca-I strips were studied. In addition, the effects of ultraviolet (UV) light (365-nm) illumination on the degradation of three PLA plastic films, Ch-I (PLA monolayer plastic films from Chronopol, Golden, CO), GII (PLA trilayer plastic films from Cargill Dow Polymers LLC), MN), and Ca-I (PLA monolayer plastic films from Cargill Dow Polymers LLC) were analyzed by a modified ASTM D5208-91 method. Results showed that irradiation had decreased the weight-average molecular weight (M_w), stress at break, percentage of elongation, and strain energy of Ca-I by 35.5, 26.7, 32.3, and 44.8%, respectively (P < 0.01). The shelf life of the irradiated Ca-I strips at 5°C and <20 ± 5% RH was about 6 months. The degradation rate of Ch-I, GII, and Ca-I with no UV light treatment at 55°C and 10% RH was 2512, 5618, and 3785 M_w/week, respectively. Under the UV light illumination (365 nm), the degradation rate of Ch-I, GII, and Ca-I, was 2982, 8722, and 7467 M_w/week, respectively. Hence, the degradation rate of GII and Ca-I was increased 55 and 97% by UV light (P < 0.008), respectively. This trend was not observed in Ch-I because its starting M_w (78,000 g/mol) was close to the tensile strength lost range (50,000 to 75,000 g/mol) of PLA films. To our knowledge, this is the first study to demonstrate that UV light does further enhance the degradation of PLA films.     

Risk management for outsourcing biomedical waste disposal – Using the failure mode and effects analysis

Using the failure mode and effects analysis, this study examined biomedical waste companies through risk assessment. Moreover, it evaluated the supervisors of biomedical waste units in hospitals, and factors relating to the outsourcing risk assessment of biomedical waste in hospitals by referring to waste disposal acts. An expert questionnaire survey was conducted on the personnel involved in waste disposal units in hospitals, in order to identify important factors relating to the outsourcing risk of biomedical waste in hospitals. This study calculated the risk priority number (RPN) and selected items with an RPN value higher than 80 for improvement. These items included “availability of freezing devices”, “availability of containers for sharp items”, “disposal frequency”, “disposal volume”, “disposal method”, “vehicles meeting the regulations”, and “declaration of three lists”. This study also aimed to identify important selection factors of biomedical waste disposal companies by hospitals in terms of risk. These findings can serve as references for hospitals in the selection of outsourcing companies for biomedical waste disposal.     

Effects of controller-pilot communication medium,flight phase and the role in the cockpit on pilots’ workload and situation awareness

This study explores the effects of communication medium, flight phase, and the role in the cockpit on pilots’ workload and situation awareness. Eight pilots with the experience of Controller-Pilot Data Link Communications (CPDLCs) participated in this simulated experiment. Two types of communication medium (voice and datalink), three types of flight phase (departure, cruise, and arrival), and two types of role (pilot flying and pilot non-flying) were investigated in the experiment. The results indicated that flight phase is a significant factor and cruise is the most suitable phase for datalink use on pilots’ acceptance, workload, and situation awareness performance. Both medium and role were not the significant factors. Since there is no significant difference on medium when no extra tasks and interferences involved in a normal flight, that the use of CPDLC can be justified during all phases of a no-event flight. In addition, the results of usability indicated that the simulated CPDLC with command selection functions proposed in this study provides good utility for the participants. In order to use the CPDLC for all phases of flight in the future, adding more command selection functions in place of typing messages by pilots and accommodating appropriate interfaces for different phases are recommended to enhance the usability of the CPDLC unit.     

Evaluation on exposures to particulate matter at a junior secondary school: a comprehensive study on health risks and effective inflammatory responses in Northwestern China

Air pollutant measurement and respiratory inflammatory tests were conducted at a junior secondary school in Xi’an, Northwestern China. Hazardous substances including particulate matters (PMs), black carbon (BC) and particle-bounded polycyclic aromatic hydrocarbons (PAHs) were quantified both indoors and outdoors of the school. Source characterization with organic tracers and particle-size distribution demonstrated that the school’s air was mostly polluted by combustion emissions from the surrounding environment. The evaluation of health assessment related to air quality was conducted by two methods, including potential risk estimation of air pollutants and direct respiratory inflammatory test. The incremental lifetime cancer risks associated with PAHs were estimated and were 1.62 × 10⁻⁶ and 2.34 × 10⁻⁶, respectively, for indoor and outdoor fine PMs. Both the values exceeded the threshold value of 1 × 10⁻⁶, demonstrating that the carcinogenic PAHs are a health threat to the students. Respiratory inflammatory responses of 50 students who studied in the sample classroom were examined with a fractional exhaled nitric oxide (FeNO) test, with the aid of health questionnaires. The average FeNO concentration was 17.4 ± 8.5 ppb, which was slightly lower than the recommended level of 20 ppb established by the American Thoracic Society for children. However, a wide distribution and 6% of the values were > 35 ppb, suggesting that the potentials were still high for eosinophilic inflammation and responsiveness to corticosteroids. A preliminary interpretation of the relationship between air toxins and respiratory inflammatory response demonstrated the high exposure cancer risks and inflammatory responses of the students to PMs in the city.

     

Effect of complex shape of pier foundation exposure on time development of scour

Environmental Fluid Mechanics - Local pier scour has been recognized as one of the most significant causes of bridge failures. Despite numerous studies on the subject of local pier scour have been...