In this study, stainless steel conductive yarns with 500 tex fineness and 14 Ω/m linear resistances were inserted into the reverse side of the knitted fabrics made from acrylic yarns. Six types of knitted fabrics with conductive yarns were produced on an E=7 gauge electronic flat bed knitting machine. Then the electromagnetic shielding efficiency (EMSE) of the sample fabrics were measured in the frequency range of 750 MHz – 3000 MHz. The EMSE variations of the sample fabrics having conductive yarns with respect to fabric structure and polarization type (vertical and horizontal) were also investigated. It was observed that the same samples showed different behaviors and have dissimilar EMSE values in different polarization conditions. When compared to horizontal polarization measurements, the vertical measurement results gave better EMSE values.

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BackgroundHealth outcomes of electromagnetic fields (EMF) from mobile phones and their base stations are of concern. Conducting multidisciplinary research, targeting children and exploring dose-response are recommended. Our objectives were to describe the mobile phone usage characteristics of high school students and to explore the association between mobile phone usage characteristics, high school EMF levels and self-reported symptoms.MethodsThis cross-sectional study’s data were collected by a survey questionnaire and by measuring school EMF levels between November 2009 and April 2011. A sample size of 2530 was calculated from a total of 20,493 students in 26 high schools and 2150 (85.0%) were included in the analysis. The frequencies of 23 symptoms were questioned and analysed according to 16 different aspects of mobile phone use and school EMF levels, exploring also dose-response. School EMF levels were measured with Aaronia Spectran HF-4060 device. Chi square and trend tests were used for univariate and logistic regression was used for multivariate analyses.ResultsAmong participants, 2021 (94.0%) were using mobile phones and 129 (6.0%) were not. Among users, 49.4% were speaking <10 min and 52.2% were sending/receiving 75 or more messages per day. Headache, fatigue and sleep disturbances were observed respectively 1.90 (95% CI 1.30–2.77), 1.78 (1.21–2.63) and 1.53 (1.05–2.21) times more among mobile phone users. Dose-response relationships were observed especially for the number of calls per day, total duration of calls per day, total number of text messages per day, position and status of mobile phone at night and making calls while charging as exposures and headache, concentration difficulties, fatigue and sleep disturbances as general symptoms and warming of the ear and flushing as local symptoms.ConclusionsWe found an association between mobile phone use and especially headache, concentration difficulties, fatigue, sleep disturbances and warming of the ear showing also dose-response. We have found limited associations between vicinity to base stations and some general symptoms; however, we did not find any association with school EMF levels. Decreasing the numbers of calls and messages, decreasing the duration of calls, using earphones, keeping the phone away from the head and body and similar precautions might decrease the frequencies or prevalence of the symptoms.Electronic supplementary materialThe online version of this article (doi:10.1186/s12940-017-0257-x) contains supplementary material, which is available to authorized users.

The electromagnetic shielding effectiveness (EMSE) of herringbone, whipcord, barathea, and crêpe woven fabrics, which are twill and sateen derivatives, woven with textured steel yarns has not been investigated so far. Therefore, in this research, textured stainless steel yarn, which has soft feeling and flexibility, required properties for clothing fabrics, was selected as a conductive yarn to produce conductive fabrics whose weaves are twill, twill and sateen derivatives. The EMSE of these common clothing fabrics woven with different conductive yarn densities were measured by free space measurement technique with different antenna polarizations, because of the possibility to obtain measurements for a large bandwidth. It was observed that all conductive clothing woven fabric samples shielded well in medium and high frequency bands, which contain 900 MHz GSM, 1800 MHz GSM, 2100 MHz 3G, and 2400 MHz Wi-Fi bands. Most of the samples give acceptable EMSE values up to 40 dB at certain frequencies. The EMSE of fabric samples would remain almost the same, although conductive yarn density changed, because of diagonally or symmetrically arranged conductive yarn floats in fabric structures. The EMSE characteristics of different weave types are investigated and it is seen that when the yarn floats arrangement is changed the EMSE characteristic changes. And also, it is observed that measurements of fabrics, positioned so that the weft yarns were parallel to the antenna polarization are similar to those of fabrics, positioned so that the weft yarns were vertical to the antenna polarization.

This paper presents the design of a biped robot, the walking trajectory generation method, and experimental results about biped walking. Walking trajectory generation is one of the deterministic factors in walking robot applications. Different approaches for stable walking trajectory are worked on in robotic research. The linear inverted pendulum model (LIPM) is an effective method used with the zero moment point (ZMP) criteria. Biped robot trunk and feet moving patterns are generated depending on these fundamental methods. In this study, generated trajectories were tested by a 12 degree of freedom (DOF) biped robot RUBI built at Dokuz Eylül University. In the experimental work, the joint angles obtained by using inverse kinematics from the generated trajectories were implemented on the robot.The results showed that even with a simple control system implementation of generated trajectories is very promising in terms of stability and reducing complexity.