Thermal mapping on male genital and skin tissues of laptop thermal sources and electromagnetic interaction

Abstract

Thermal mapping on male genital and skin tissues of laptop thermal sources and electromagnetic interaction Safari M, Mosleminiya N, Abdolali A. Thermal mapping on male genital and skin tissues of laptop thermal sources and electromagnetic interaction. Bioelectromagnetics. 2017 Aug 11. doi: 10.1002/bem.22068. Abstract Since the development of communication devices and expansion of their applications, there have been concerns about their harmful health effects. The main aim of this study was to investigate laptop thermal effects caused by exposure to electromagnetic fields and thermal sources simultaneously; propose a nondestructive, replicable process that is less expensive than clinical measurements; and to study the effects of positioning any new device near the human body in steady state conditions to ensure safety by U.S. and European standard thresholds. A computer simulation was designed to obtain laptop heat flux from SolidWorks flow simulation. Increase in body temperature due to heat flux was calculated, and antenna radiation was calculated using Computer Simulation Technology (CST) Microwave Studio software. Steady state temperature and specific absorption rate (SAR) distribution in user's body, and heat flux beneath the laptop, were obtained from simulations. The laptop in its high performance mode caused 420 (W/m2 ) peak two-dimensional heat flux beneath it. The cumulative effect of laptop in high performance mode and 1 W antenna radiation resulted in temperatures of 42.9, 38.1, and 37.2 °C in lap skin, scrotum, and testis, that is, 5.6, 2.1, and 1.4 °C increase in temperature, respectively. Also, 1 W antenna radiation caused 0.37 × 10-3 and 0.13 × 10-1. ncbi.nlm.nih.gov Excerpts Findlay and Dimbylow [2010] carried out one such study on SAR in the body of a sitting 10-year-old at 2.4 and 5 GHz. They found maximum peak localized three-dimensional (3D) SAR of 3.99 × 10−3 (W/kg) in the torso area. It should be specified that this study only considered thermal effects on men; however, laptop antenna could have non-thermal effects on the user's body or pregnant women, including DNA fraction [Nagaoka et al., 2007; Zoppetti et al., 2011; Avendano et al., 2012], but such non-thermal effects are not considered in the present paper. Since maximum allowed power consumption for an array of antennas designed for this purpose is 1 W and there were two antennas, each one consumed up to 0.5 W of power. However, in normal conditions, Wireless Local Area Network (WLAN) antennas can radiate using only 10 mW [Guterman et al., 2009]. It should be noted that the given values of SAR were normalized to 1 W peak antenna power output, while typically a WLAN antenna radiates about 10 mW; therefore, for a real world operating system, maximum SAR of 0.37 × 10−3 and 0.18 × 10−3 (W/kg) is expected for 2 and 1 active antennas, respectively, which are 104 times lower than the European safety limit (2 W/kg) [IEEE Standard for Safety Levels with Respect to Humans, 2005]. Also, maximum SAR of 0.13 × 10−3 (W/kg) is expected for a WLAN antenna radiation power of about 10 mW operating at 5 GHz, which is still lower than safety limits. ... maximum temperature on surface of scrotum skin of the laptop user in the studied position was 38.1 °C, which was 2.1 °C higher than normal temperature in absence of the laptop in the simulation. It can be inferred from the aforementioned works that increase in scrotal temperature can result in reduction of sperm motility, which consequently enhances the probability of infertility, lessens sperm production, decreases sperm concentration by 56% [Hjollund et al., 2002], increases ROS, and negatively affects sperm morphology, increasing the number of sperm with physical dimensions different from those of normal sperm. A method of simulating thermal mapping of positioning laptop on laps of an adult man was developed. To tackle this problem, we exploited computer simulation and, to make the simulation close to the actual problem, we created 3D models of an actual laptop (Sony FW 590 Gab), antennas, and human phantom with inhomogeneous body, large number of tissues, and dispersion properties. We employed a commercial laptop Wi-Fi antenna at 2.4 GHz and a dipole antenna at 5 GHz, thermal sources with radiation powers, and human body voxel consisting of 97 tissues which were described previously. In the simulation, maximum SAR in human body was calculated 0.37 × 10−3 and 0.13 × 10−1 (W/kg) at 2.4 and 5 GHz, respectively, which was negligible according to IEEE standards; thus, the major calculated temperature elevation was due to laptop thermal sources. The temperature in glans penis, lap skin, lap muscles, and testes increased up to 37.8, 42.9, 38.8, and 37.2 °C, respectively, which was in line with clinical studies of thermal effect. Hence, the proposed method can be replicated for other scenarios. It is worth noting that the presented result cannot be easily generalized to other devices or human models. However, the whole method is replicable for similar phenomena. The recommended subject for future works can be used with the presented method for determining the effect of laptop and other devices on adult pregnant women and similar cases.

AI evidence extraction

Main findings

Computer simulations estimated that a laptop in high performance mode produced a peak heat flux of 420 W/m^2 beneath it. With combined laptop thermal sources and 1 W antenna radiation, simulated temperatures reached 42.9°C (lap skin), 38.1°C (scrotum), and 37.2°C (testis), corresponding to increases of 5.6°C, 2.1°C, and 1.4°C, respectively. Simulated SAR values (normalized to 1 W antenna power) were described as negligible relative to IEEE/European limits, and the major temperature elevation was attributed to laptop thermal sources rather than RF exposure.

Outcomes measured

• Steady-state temperature distribution in lap skin/scrotum/testis and other tissues
• Specific absorption rate (SAR) distribution
• Heat flux beneath laptop

Limitations

• Simulation study (no clinical/epidemiologic measurements reported)
• Results stated as not easily generalizable to other devices or human models
• Non-thermal effects were explicitly not considered
• SAR values were normalized to 1 W peak antenna power; typical WLAN power noted as lower

Suggested hubs

• school-wi-fi (0.2)
  Includes WLAN/Wi-Fi antenna exposures (2.4 and 5 GHz), though context is laptop-on-lap rather than school setting.

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        "source": "laptop",
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        "sar_wkg": null,
        "duration": "steady state (simulation)"
    },
    "population": "Adult man (human phantom/voxel model) with male genital and skin tissues (simulation)",
    "sample_size": null,
    "outcomes": [
        "Steady-state temperature distribution in lap skin/scrotum/testis and other tissues",
        "Specific absorption rate (SAR) distribution",
        "Heat flux beneath laptop"
    ],
    "main_findings": "Computer simulations estimated that a laptop in high performance mode produced a peak heat flux of 420 W/m^2 beneath it. With combined laptop thermal sources and 1 W antenna radiation, simulated temperatures reached 42.9°C (lap skin), 38.1°C (scrotum), and 37.2°C (testis), corresponding to increases of 5.6°C, 2.1°C, and 1.4°C, respectively. Simulated SAR values (normalized to 1 W antenna power) were described as negligible relative to IEEE/European limits, and the major temperature elevation was attributed to laptop thermal sources rather than RF exposure.",
    "effect_direction": "mixed",
    "limitations": [
        "Simulation study (no clinical/epidemiologic measurements reported)",
        "Results stated as not easily generalizable to other devices or human models",
        "Non-thermal effects were explicitly not considered",
        "SAR values were normalized to 1 W peak antenna power; typical WLAN power noted as lower"
    ],
    "evidence_strength": "low",
    "confidence": 0.7399999999999999911182158029987476766109466552734375,
    "peer_reviewed_likely": "yes",
    "keywords": [
        "laptop",
        "thermal mapping",
        "male genital",
        "scrotum",
        "testis",
        "skin",
        "heat flux",
        "SAR",
        "Wi-Fi",
        "2.4 GHz",
        "5 GHz",
        "computer simulation",
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        "SolidWorks"
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    "suggested_hubs": [
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            "weight": 0.200000000000000011102230246251565404236316680908203125,
            "reason": "Includes WLAN/Wi-Fi antenna exposures (2.4 and 5 GHz), though context is laptop-on-lap rather than school setting."
        }
    ]
}

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