Working in a Physically Dangerous Work Environment: Employee Vitality and Sustainable Behavior

There is a limited understanding of the antecedents and consequences of employee vitality during war zone exposure. The current study is one of the first ones to investigate the direct effects of perceived danger on employee vitality by collecting data from Afghanistan, one of the most dangerous countries in the world. Furthermore, it was investigated how employee vitality affects sustainable behavior at the workplace. The hypotheses of the study have been tested by using data from two surveys collected from 192 employees working in small-sized private businesses in Afghanistan. The results indicate that high levels of perceived danger negatively impact employee vitality at work. In addition, we found that employees with vitality engage in more pro-environmental behavior in the workplace. The engagement of vital employees in pro-environmental behavior is higher among those employees who have a high level of environmental awareness. This paper concludes by presenting the limitations and implications of this study, as well as highlighting potential avenues for future research

Bit error rate measurement of free space optical communication links under laboratory controlled conditions

This paper outlines the experimental investigation of the fog effect on the bit error rate (BER) performance of the free space optical (FSO) communication link under a controlled laboratory environment. The link transmittance and the received signal Q-factor are measured against different levels of fog densities. The link visibility derived from fog attenuation measurement is used to characterize the fog within the chamber. Moreover, the effect of using different average transmitted optical communication power (Popt) on the transmittance and received Q-factor of the link is also studied for light and dense fog densities

Investigation of Underwater Optical Wireless Communications with Turbulence

Turbulence is due to the random variations of the refractive index of the medium (in this case water), which leads to fluctuation or fading of the received light intensity. In wireless communications including underwater optical wireless communications the link performance is greatly affected. In this paper, we investigate the effect of turbulence on the probability density function (PDF) of the received light intensity. We show that lognormal and negative exponential distributions are fitted well with the PDFs of the received light intensity in weak-to-strong and saturated turbulence regimes. The goodness of fit test is performed to validate the conformity of these two distributions with the simulation results. Furthermore, we investigate the effect of the divergence angle of the Gaussian beam transmitter, the receiver’s aperture diameter and field of view on the scintillation index

Investigation of the Scattering Noise in Underwater Optical Wireless Communications

In underwater optical wireless communications (UOWC), scattering of the propagating light beam results in both intensity and phase variations, which limit the transmission link range and channel bandwidth, respectively. Scattering of photons while propagating through the channel is a random process, which results in the channel-dependent scattering noise. In this work, we introduce for the first time an analytical model for this noise and investigate its effect on the bit error rate performance of the UOWC system for three types of waters and a range of transmission link spans. We show that, for a short range of un-clear water or a longer range of clear water, the number of photons experiencing scattering is high, thus leading to the increased scattering noise. The results demonstrate that the FEC limit of 3×10−3 and considering the scattering noise, the maximum link spans are 51.5, 20, and 4.6 m for the clear, coastal, and harbor waters, respectively

Impact of Number of LEDs on An Optical Camera Communication Based Indoor Positioning System

Optical camera communications (OCCs) technology utilizes lighting infrastructure for both illumination and data transmission and a camera for the data receiver. Recently, implementing OCC for indoor positioning has drawn a lot of attention.We consider an indoor environment with some light emitting diodes (LEDs) lighting access points for positioning and estimate the location of the camera using the angle viewed from the camera's lens. In this work, impact of number of LEDs on the preciseness of the positioning is investigated theoretically and validated experimentally. We show that increasing the number of LEDs has a significant effect on the performance of the proposed indoor positioning system (IPS)

Investigation of a WDM M-QAM RoF-RoFSO System

The radio over fiber (RoF) technology combines the advantages of radio frequency (RF) and optical communication systems. Hybrid RoF and radio over free space optics (RoFSO) is a solution for the last mile access networks in urban areas and in areas where installation of RoF links is impractical and costly. In this work we introduce a 4-, 16- and 64-quadrature amplitude modulation (QAM) hybrid RoF-RoFSO communication system and investigated the inter-channel interference and the effects of atmospheric turbulence on the FSO section of the link

Assessment of COVID-19 among healthcare workers in Non-COVID pediatrics departments, Tehran, Iran: A cross-sectional study

Objective: The severe acute respiratory syndrome coronavirus 2(SARS COV 2) is an important health problem, which is widespread around the world. This study describes the characteristics of COVID-19 infections in healthcare workers (HCWs), related factors and deaths in Non- COVID pediatrics departments from the early phases of COVID-19 pandemic; February 20th, 2020toJanuary19th, 2021 in Tehran-Iran. Materials and Methods: It is a multi-center cross-sectional descriptive study. The standardized questionnaire was designed according Demographics information, Coronavirus disease (COVID-19) history in HCW and Using and access to Personal Protective Equipment (PPE). All data analysis was performed by SPSS software version 21. Results: Of the 82 HCW, 67 (81.7%) was female. The median age was 37.6 ±10.3 years old (rang 24 to 65). 44 (53.6%) were nurses, 14 (17 %) pediatrics residents,13 (15.9%) pediatrics faculty members,8(9.8%) environmental services staff and 3(3.7%) secretaries. Twelve out of our cases (14.6%) have underlying medical diseases. Thirty-six (42.7%) confirmed COVID19. In COVID-19 positive group 28(80%) were female. Among whom 51.4% were identified nurses, 17% faculty member and14.3% pediatrics residents. Secretaries and environmental services staff are more vulnerable job category in this study. Eighty-six percent of them follow protective health protocol and use PPE. COVID-19 cases were infected more on July 2020(25.7%), November 2020 (17.1%) and August 2020(14.2%).   Conclusion: Approximately one half of HCWs in non-Covid-19 pediatrics department infected with corona virus 2 (SARS_COV_2) and most of them thought they were infected in workplac

Fundamental Analysis of Vehicular Light Communications and the Mitigation of Sunlight Noise

Intelligent transport systems (ITS) rely upon the connectivity, cooperation and automation of vehicles aimed at the improvement of safety and efficiency of the transport system. Connectivity, which is a key component for the practical implementation of vehicular light communications (VeLC) systems in ITS, must be carefully studied prior to design and implementation. In this paper, we carry out a performance evaluation study on the use of different vehicle taillights (TLs) as the transmitters in a VeLC system. We show that, the transmission coverage field of view and the link span depend on TLs illumination patterns and the transmit power levels, respectively, which fail to meet the typical communication distances in vehicular environments. This paper proposes an infrared-based VeLC system to meet the transmission range in daytimes under Sunlight noise. We show that, at the forward error correction bit error rate limit of 3.8 10^-3, the communication distances of the proposed link are 63, 72, and > 89 m compared with 4.5, 5.4 and 6.3 m for BMWs vehicle TL at data rates of 10, 6, and 2 Mbps, respectively

Special Issue on Light Communications: Latest Advances and Prospects

The wireless information carrier shift from the radio frequencies to optical frequencies has been studied in increasing detail since the invention of the laser in the 1960s. With the advent of optical fiber communications and their global use, we have seen a growing interest in the field of optical wireless communications (OWC) for front- and back-haul access networks and beyond as part of fifth-generation (5G) wireless networks. OWC has found niche applications in a wide range of systems, from short-range indoor to long-range outdoor and very long deep space and inter-satellite links. New components, such as visible light-emitting sources, image sensors, advanced signal processing techniques, multi-input multi-output, and machine learning are pushing the OWC technology into new application areas such as vehicular communications, smart environments, medical, manufacturing, etc., as part of 5G wireless networks and the emerging 6G networks and beyond.This Special Issue was put together with the goal of bringing together the latest research and development in wireless light communications. A total of 53 submissions were received, and 24 were selected for publication in this Special Issue. The published works present novel results mainly on outdoor and indoor applications of light communications, while a few papers also address broader areas. We briefly present these works in the following sections

ALKYL IMIDAZOLINES AND THEIR ETHOXYLATED DERIVATIVES AS ANTIOXIDANTS FOR HYDROCARBON PRODUCTS

Alkyl imidazolines have been reportedly used in a wide range of industrial formulations with different applications. Ethoxylated alkyl imidazolines with appropriate ethoxylation degrees can be used as antioxidants and retarders in the formation of peroxides resulting from oxidation in hydrocarbon media. In this work, ethoxylated imidazolines were shown to be more effective in hydrocarbon media in comparison with reference antioxidants. According to the experimental results, ethoxylated alkyl imidazolines (12 moles EO), as an antioxidant, were twice as efficient as zinc dialkyldithiophosphoric acid (ZDDP)