Operational assessment of the 5-h on/10-h off watchstanding schedule on a US Navy ship: sleep patterns,mood and psychomotor vigilance performance of crewmembers in the nuclear reactor department

We assessed sleep patterns, psychomotor vigilance performance, work demands and mood of 77 crewmembers of USS NIMITZ (CVN-68) on the rotating 5-h on/10-h off (5/10) watchstanding schedule. Within the 3-day cycle of the 5/10, sleep occurred at distinctly different times each day. On two of these days, sailors typically received only brief, 4-h sleep episodes followed by periods of sustained wakefulness (approximately 22 and 20 h). Crewmembers received approximately seven hours of sleep daily, but reported excessive fatigue and dissatisfaction with their schedule. Crewmembers’ mood worsened significantly over the course of the underway phase. Psychomotor vigilance performance (reaction times, lapses) was significantly degraded compared to performance when working circadian-aligned schedules. Overall, standing watch on the 5/10 schedule, combined with other work duties, resulted in poor sleep hygiene. Crewmembers on the 5/10 experienced periodic bouts of sustained wakefulness and accrued a significant sleep debt due to extended workdays and circadian-misaligned sleep.

Practitioner summary: We assessed crewmembers’ sleep patterns, psychomotor vigilance performance and work demands when working a rotating 5-h on/10-h off (5/10) watchstanding schedule. The 5/10, combined with other work duties, resulted in poor sleep hygiene. Crewmembers experienced periodic bouts of sustained wakefulness and accrued a significant sleep debt due to extended workdays and circadian-misaligned sleep.     

Adaptive Terminal ILC for Iteration‐varying Target Points

Terminal iterative learning control (TILC) has been developed to reduce the error between system output and a fixed desired point at the terminal end of operation interval over iterations. In this work, the desired terminal point is not fixed but allowed to change run‐to‐run among a set of fixed points and a new adaptive terminal iterative learning control scheme is developed to achieve learning objective over iterations. The control signal is updated from the measured terminal value at the end of a run, instead of the whole output trajectory. Although the reference terminal point is iteration‐varying, the new adaptive TILC guarantees that the tracking error converges to zero iteratively. Both rigorous mathematical analysis and simulation results confirm the applicability and effectiveness of the proposed approach.     

Editorial

This special issue is to honor professor Tzyh-Jong Tarn for his 80 birthday. Prof. Tarn is a world outstanding expert in Systems and Control Theory, Robotics and Quantum Control, etc. He received the D.Sc. degree in control system engineering from Washington University at St. Louis, Missouri, U.S.A. He is at present a Professor in the Department of Electrical Engineering and the Director of the Center for Robotics and Automation at Washington University. Dr. Tarn served as the President of the IEEE Robotics and Automation Society, the Director of IEEE Division X (Systems and Control), and a member of the IEEE Board of Directors. The Japan Foundation for the Promotion of Advanced Automation Technology presented him with the Best Research Article Award in March 1994. He also is a recipient of the Best Paper Award at the 1995 IEEE/RSJ International Conference on Intelligent Robots and Systems. Prof. Tarn has also made significant contribution to enhance the academic exchange between Chinese scholars and world systems science and automation society. This special issues contains 10 papers covering 1) Robot Control; 2) Quantum Control; 3) System Identification; 4) Advanced linear/Nonlinear Control Technique; and 5) Multi-agent Systems. These fields are closely related to Prof. Tarn''s research interests. The papers are arranged according to their categories....     

Dual Functionalization of Liquid‐Exfoliated Semiconducting 2H‐MoS2 with Lanthanide Complexes Bearing Magnetic and Luminescence Properties

Liquid exfoliated, atomically thin semiconducting transition metal dichalcogenides (TMDs), as inorganic equivalents of graphene, have attracted great interest due to their distinctive physical, optoelectronic, and chemical properties. Functionalization of 2D TMDs brings new prospects for applications in optoelectronics, quantum technologies, catalysis, and medicine. In this report, dual functionalization of 2D semiconducting 2H‐MoS₂ nanosheets through simultaneous incorporation of magnetic and luminescent properties is demonstrated. A facile method is proposed for tuning the properties of the TDM semiconductors and accessing multimodal platforms, consisting in covalent grafting of lanthanide complexes onto the surface of 2D TMDs. Dual functionalization of liquid‐exfoliated MoS₂ nanosheets is demonstrated simultaneously with both europium (III) and gadolinium (III) complexes to form a colloidally stable luminescent (with millisecond lifetimes) and paramagnetic MoS₂‐based nanohybrid material. This work is the first example of transition metal dichalcogenide nanosheets functionalized with preformed lanthanide complexes. These findings open new prospects for covalent functionalization of TMDs with molecular species bearing specific functionalities as a means to tune the optoelectronic properties of the semiconductors, in order to create advanced materials and devices with a wide range of functionalities.     

When We Stop Talking Politics: The Maintenance and Closing of Conversation in Contentious Times

Despite the democratic significance of citizen talk about politics, the field of communication has not considered how that talk is weathering stresses facing our civic culture. We examine political talk during an archetypal case of political contentiousness: the recall of Governor Scott Walker of Wisconsin in 2012. Pairing qualitative and quantitative methods, we show that a fracturing of civic culture took place in which many citizens found it impossible to continue political discussion. Individuals at fault lines of contention, by nature of occupation, geographic location, or other personal circumstance, were most prone to this breakdown. Our results call into question the ability of talk to bridge political and social differences in periods of polarization and fragmentation, with implications for democratic functioning.     

Transient flashing propellant flow models to predict internal flow characteristics,spray velocity,and aerosol droplet size of a pMDI

Despite the popularity of the pMDI as an asthma remedy, the mechanism leading to spray generation is elusive, mainly due to small length scales and short time scale, causing experimental difficulties to obtain flow information. This mechanism involves transient development of two-phase flashing propellant flow inside pMDI actuator as well as transfer of heat, mass, and momentum between the liquid and vapor phase. Variations in the rate of such interphase phenomena dictate the two-phase mass flow rate emission, which itself determines spray velocity and droplet size. In this work, we compare the performance of existing two-phase flow models to predict the flow conditions and the rate of propellant flow through a pMDI actuator: the homogenous equilibrium model (HEM), the slip equilibrium model (SEM), and the homogenous frozen model (HFM). The velocity prediction of the HFM was found to be in good agreement with phase Doppler anemometry (PDA) data indicating the metastable nature of the emitted propellant spray. This work also considers Clark's correlation for the aerosol droplet size based on the results of the flow model. The results of the correlation were compared with PDA droplet size measurements. Clark's correlation was found to be effective in predictions of the temporal droplet size variations. However, the value of an empirical constant had to be tuned to fix the droplet size for a given combination of formulation, device, and to a lesser extent also the distance from the spray orifice where predictions are compared with PDA data. This highlights the need to develop first principle atomization models without the need for case-by-case adjustment.

© 2017 American Association for Aerosol Research     

Real-time monitoring of peanut drying parameters in semitrailers

Knowledge of peanut drying parameters, such as temperature and relative humidity of the ambient air, temperature and relative humidity of the air being blown into the peanuts, and kernel moisture content, is essential in managing the dryer for optimal drying rate. The optimal drying rate is required to preserve quality and desired flavor. In the current peanut-drying process, such parameters are elusive in real time and are either not measured or only measured periodically by an operator. A peanut-drying monitoring system, controlled by an embedded microcontroller and consisting of relative humidity and temperature sensors and a microwave peanut moisture sensor, was developed to monitor drying parameters in real time. It was deployed during the 2014 peanut harvest season at a peanut buying point in central Georgia, USA. It was placed in 45-ft (13.7-m) drying semitrailers to monitor in-shell kernel moisture content, temperature of the drying peanuts, temperature, and relative humidity of the exhaust air from the peanuts and relative humidity of the air being blown into the peanuts in real time. In-shell kernel moisture content was determined with a standard error of performance of 0.55% moisture content when compared to the reference oven-drying method. Data from drying parameters were time-stamped and stored on a CompactFlash card every 12?s and were used to assess the efficiency of dryer control settings. Ambient air conditions were measured by an on-site weather station. Results of the study support the value of such a monitoring system and show that implementation of the system for dryer control has the potential for saving a buying point, in the current economical context, as much as $22,000 annually in costs of electric energy and propane.     

Digital alkali resist prints on polyester

In earlier papers we have described sulphite‐based and secondary amine‐based resist printing of cotton using ink‐jet procedures. This paper describes the chemical resist printing of polyester fabrics padded with disperse dyes to create a white image on a coloured background. Polyester grounds have been prepared by the pad‐dry ‘dyeing’ of polyester fabrics with alkali‐clearable disperse dyes, such as a Dianix PC (DyStar) or a Dianix SF (DyStar) dye, and subsequently ink‐jet printed with sodium carbonate based ink formulations to yield a white image on a solid ground following high temperature steaming and appropriate wash‐off procedures. Coloured images have been achieved by a two‐step process whereby the coloured ground fabric was initially printed with an alkali‐based ink and then overprinted in a second step with an illuminating ink formulation containing an alkali stable disperse dye, such as a Dianix AD (DyStar) or Serilene ADS (Yorkshire Chemicals).