scholarly journals Electromagnetic Exposure Dosimetry Study on Two Free Rats at 1.8 GHz via Numerical Simulation

2021 ◽  
Vol 9 ◽  
Author(s):  
Xianghui Wang ◽  
Chengjie Xia ◽  
Lu Lu ◽  
Hongxin Qi ◽  
Jie Zhang
Keyword(s):  
Numerical Simulation ◽  
Orientation Angle ◽  
Exposure Dose ◽  
Simulation Software ◽  
Whole Body ◽  
Precise Control ◽  
Variation Rate ◽  
Average Variation ◽  
Processing Techniques ◽  
The Impact

Normally, the impact of electromagnetic exposure on human health is evaluated by animal study. The biological effect caused by electromagnetic exposure on such experimental animals as rats has been proven to be dose-dependent. However, though the dose of radio frequency (RF) electromagnetic exposure described by the specific absorbing rate (SAR) on fixed rats has been relatively well-studied utilizing the numerical simulations, the dosimetry study of exposure on free rat is insufficient, especially in the cases of two or more free rats. Therefore, the present work focuses on the variation of SAR caused by the existence of neighboring free rat in the same cage. Here, infrared thermography was used to record the activity of the two free rats who lived in the same cage that mounted at the far-field region in the microwave darkroom for a duration of 48 h. Then, using image processing techniques, the relative positions and orientations of the two rats are identified, which are defined by three parameters, such as the relative distance (d), relative direction angle (α), and relative orientation angle (β). Using the simulation software XFdtd 7.3, the influence of d, α, and β on the whole-body average SAR (WB-avgSAR) of the rats exposed to 1.8 GHz electromagnetic wave was calculated and analyzed. Then, the average variation of WB-avgSAR of the two rats compared with that of a single rat within 48 h was calculated. The numerical simulation results showed that the relative posture position described by (d, α, and β) of the two rats affects their WB-avgSAR and leads to fluctuations at different positions. However, the variation rate of the 48-h-average WB-avgSAR was only 10.3%, which implied that the over-time average SAR of two or more rats can be roughly described by the WB-avgSAR of a single free rat, except when a real-time precise control of exposure dose is necessary.

scholarly journals Joint Minimization of Uplink and Downlink Whole-Body Exposure Dose in Indoor Wireless Networks

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
D. Plets ◽  
W. Joseph ◽  
K. Vanhecke ◽  
G. Vermeeren ◽  
J. Wiart ◽  
...  
Keyword(s):  
Wireless Networks ◽  
Power Control ◽  
Total Dose ◽  
Exposure Dose ◽  
Base Stations ◽  
Phone Call ◽  
Whole Body ◽  
Indoor Wireless ◽  
The Impact ◽  
Dose Reductions

The total whole-body exposure dose in indoor wireless networks is minimized. For the first time, indoor wireless networks are designed and simulated for a minimal exposure dose, where both uplink and downlink are considered. The impact of the minimization is numerically assessed for four scenarios: two WiFi configurations with different throughputs, a Universal Mobile Telecommunications System (UMTS) configuration for phone call traffic, and a Long-Term Evolution (LTE) configuration with a high data rate. Also, the influence of the uplink usage on the total absorbed dose is characterized. Downlink dose reductions of at least 75% are observed when adding more base stations with a lower transmit power. Total dose reductions decrease with increasing uplink usage for WiFi due to the lack of uplink power control but are maintained for LTE and UMTS. Uplink doses become dominant over downlink doses for usages of only a few seconds for WiFi. For UMTS and LTE, an almost continuous uplink usage is required to have a significant effect on the total dose, thanks to the power control mechanism.

Numerical Studies on Low-Velocity Impact Failure Response of Al 1100 under Blunt and Hemispherical Impactors

2018 ◽  
Vol 917 ◽  
pp. 218-222 ◽  
Author(s):  
Sonika Sahu ◽  
Mohd Zahid Ansari ◽  
Chong Du Cho
Keyword(s):  
Numerical Simulation ◽  
Impact Analysis ◽  
Failure Modes ◽  
Simulation Software ◽  
Low Velocity Impact ◽  
Impact Behavior ◽  
Nose Radius ◽  
Low Velocity ◽  
Velocity Impact ◽  
The Impact

Numerical simulation is performed to study the deformation and failure modes of Al 1100 plate of 2.4 mm thickness, subjected to low-velocity impact. Blunt and hemispherical nose shaped impactors are used in this study. The quasi-static tensile test is performed at a strain rate of 0.01/s to obtain the Johnson-Cook material parameters which are used in numerical simulation software, ABAQUS/CAE to perform impact analysis. Mesh convergence study is carried out to decide the appropriate number of elements for numerical analysis. The impact behavior of Al 1100 plate for each impactor shapes are studied at 22 J impact energy. Result indicate that increased in the nose radius of impactor will increase the amount of deformation energy for aluminium plate.

Study on the Influence of Ice-Water Coupling on Numerical Calculation of Ice Load

2018 ◽  
Author(s):  
Hui Li ◽  
Zheng Yang ◽  
Yan Feng ◽  
Yu-Bo Wang ◽  
Si-Yu Wang
Keyword(s):  
Numerical Simulation ◽  
Numerical Calculation ◽  
Sea Ice ◽  
Sea Water ◽  
Coupling Effect ◽  
Simulation Software ◽  
Ice Load ◽  
Local Strength ◽  
Ice Water ◽  
The Impact

The interaction between sea ice and sea water is a complicated fluid-solid coupling dynamic process during the operation of polar ships. Using the finite element numerical simulation software LS-DYNA to simulate the continuous ice breaking of icebreaker, the ice load numerical calculation method considering the ice water coupling is presented. The effect of ice water coupling on ice load is studied. Based on the ice pool test data and the calculated results of this paper, the accuracy and rationality of the algorithm are verified. On this basis, the multiple factors affecting the coupling between sea ice and sea water are further studied, including the thickness of sea ice and the collision velocity of ship and ice which are affected by the environment of different polar sea areas. By simulating the numerical results obtained from the collision ice breaking of the targeted ship, the influence of various factors on the coupling effect between sea ice and sea water is summarized, and the local strength of the hull head structure is checked and evaluated. Furthermore, the impact-type icebreaking ability of the hull is put forward, which has certain guiding significance for the development of ship ice collision numerical simulation.

scholarly journals A numerical study to improve the position and angle of the producer gas injector inside the intake manifold to minimize emissions and efficiency enhancement of a bi engine

2021 ◽  
pp. 100-109
Author(s):  
Hussein A. Mahmood ◽  
Ali O. Al-Sulttani ◽  
Osam H. Attia ◽  
Nor Mariah. Adam
Keyword(s):  
Numerical Simulation ◽  
Numerical Study ◽  
Single Point ◽  
Flow Characteristics ◽  
Engine Performance ◽  
Simulation Software ◽  
Petrol Engine ◽  
Intake Manifold ◽  
Producer Gas ◽  
The Impact

To develop a petrol engine so that it works under the bi-engine pattern (producer gas-petrol) without any additional engine modifications, a single-point injection method inside the intake manifold is a simple and inexpensive method. Still, it leads to poor mixing performance between the air and producer gas. This deficiency can cause unsatisfactory engine performance and high exhaust emissions. In order to improve the mixing inside the intake manifold, nine separate cases were modelled to evaluate the impact of the position and angle orientation inside the intake manifold on the uniformity and spread of the mixture under AFR=2.07. A petrol engine (1.6 L), the maximum engine speed (8000 rpm), and bi-engine mode (petrol-producer gas engine). The employ of the numerical simulation software (ANSYS workbench 19), the propagation, flow characteristics, and uniformity of the blend within the nine different cases were evaluated. According to the outcomes of the numerical simulation, it was found that creating vortices and turbulent flow for the producer gas and air inside the intake manifold is the perfect method to obtain a uniformity mixture of air and producer gas inside the intake manifold. In addition, extending the blending duration allows air and producer gas fuel to be mixed efficiently. Furthermore, the greatest uniformity and the maximum spread rate at the outlet of manifold are obtained in cases 1, 4, and 7, when the producer gas injector location is constant (P1, P2 or P3). In addition, the weakest spread of producer gas at the outlet of the manifold is observed in case 9 in comparison with the other cases. Moreover, it is observed that case (1) generated the maximum uniformity index (UI) level

scholarly journals Numerical Simulation of Geostress and Support of Roadway Crossing Strata in Complex Stress Condition

2012 ◽  
Vol 446-449 ◽  
pp. 1781-1784
Author(s):  
Tong Xu Wang ◽  
Lai Yuan Li ◽  
Wen Hai Zheng ◽  
Yang Liu ◽  
Tao Hou ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Mining Area ◽  
Complex Stress ◽  
Simulation Software ◽  
Stress Variation ◽  
Roof Structure ◽  
Rock Structure ◽  
Stability Classification ◽  
The Stability ◽  
The Impact

Affected by a group of underground chambers and gobs of working faces, the track sub-inclined shaft of 430 mining area in Geting coal mine, which crosses coal seam and faults repetitively, lies in high and complex stress environment. Based on geostress results measured in the field, FLAC3D numerical simulation software was used to simulate the regional geostress in the area near the roadway, referring to the impact of the gobs and chambers. And the stress variation law along the roadway was given at last. Then the roadway roof structure zone chart was drawn according to the detection results with the rock video detection recorder. Finally, stability of different sections of the roadway and the support advice corresponding to each section was gained. The results show that comprehensive consideration of geostress variation law and surrounding rock structure is necessary in the stability classification and the support of roadways. The research methods and ideas given in this paper is feasible.

scholarly journals Numerical analysis of the impact of natural ventilation on the Indoor Air Quality and Thermal Comfort in a classroom

2019 ◽  
Vol 111 ◽  
pp. 01023 ◽  
Author(s):  
George-Mãdãlin Chitaru ◽  
Andrei Istrate ◽  
Tiberiu Catalina
Keyword(s):  
Numerical Simulation ◽  
Air Quality ◽  
Thermal Comfort ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Natural Ventilation ◽  
Simulation Software ◽  
Educational Institutions ◽  
Research School ◽  
The Impact

Indoor air quality (IAQ) inside educational institutions is an important topic in the field of building and health research. School absenteeism and educational performance have been linked to poor air quality inside classrooms. A numerical simulation software has been used to test 5 different scenarios of natural ventilation during summer and winter. CO2 levels, air relative humidity, operative temperature and PMV were used as indoor air quality and thermal comfort indicators. Results have shown high CO2 and humidity levels when all windows are closed, and a variable improvement when different natural ventilations strategies are employed. A detailed procedure for the numerical simulation has been presented.

Impact of Raw Materials and Processing Techniques on The Microbiological Quality of Egyptian Domiati Cheese

2020 ◽  
Keyword(s):  
Raw Materials ◽  
Microbiological Quality ◽  
Raw Milk ◽  
Plate Count ◽  
E Coli ◽  
Fresh Cheese ◽  
Processing Techniques ◽  
The Impact ◽  
Total Yeast

Domiati cheese is the most popular brand of cheese ripened in brine in the Middle East in terms of consumed quantities. This study was performed to investigate the impact of the microbiological quality of the used raw materials, the applied traditional processing techniques and ripening period on the quality and safety of the produced cheese. Three hundred random composite samples were collected from three factories at Fayoum Governorate, Egypt. Collected samples represent twenty-five each of: raw milk, table salt, calf rennet, microbial rennet, water, environmental air, whey, fresh cheese, ripened cheese & swabs from: worker hands; cheese molds and utensils; tanks. All samples were examined microbiologically for Standard Plate Count (SPC), coliforms count, Staphylococcus aureus (S. aureus) count, total yeast & mould count, presence of E. coli, Salmonellae and Listeria monocytogenes (L. monocytogenes). The mean value of SPC, coliforms, S. aureus and total yeast & mould counts ranged from (79×102 CFU/m3 for air to 13×108 CFU/g for fresh cheese), (7×102 MPN/ cm2 for tank swabs to 80×106 MPN/ml for raw milk), (9×102 CFU/g for salt to 69×106 CFU/g for fresh cheese) and (2×102 CFU/cm2 for hand swabs to 60×104 CFU/g for fresh cheese), respectively. Whereas, E. coli, Salmonella and L. monocytogenes failed to be detected in all examined samples. There were significant differences in all determined microbiological parameters (p ≤0.05) between fresh and ripened cheese which may be attributed to different adverse conditions such as water activity, pH, salt content and temperature carried out to improve the quality of the product.

A Melanocortin-4 Receptor Agonist Induces Skin and Hair Pigmentation in Patients with Monogenic Mutations in the Leptin-Melanocortin Pathway

2021 ◽  
pp. 1-10
Author(s):  
Varvara Kanti ◽  
Lia Puder ◽  
Irina Jahnke ◽  
Philipp Maximilian Krabusch ◽  
Jan Kottner ◽  
...  
Keyword(s):  
Leptin Receptor ◽  
Skin Pigmentation ◽  
Gene Mutations ◽  
Continuous Treatment ◽  
Whole Body ◽  
Hair Color ◽  
Phase 2 ◽  
Loss Of Function ◽  
The Impact ◽  
Over Time

<b><i>Background and Objectives:</i></b> Gene mutations within the leptin-melanocortin signaling pathway lead to severe early-onset obesity. Recently, a phase 2 trial evaluated new pharmacological treatment options with the MC4R agonist <i>setmelanotide</i> in patients with mutations in the genes encoding proopiomelanocortin (POMC) and leptin receptor (LEPR). During treatment with <i>setmelanotide,</i> changes in skin pigmentation were observed, probably due to off-target effects on the closely related melanocortin 1 receptor (MC1R). Here, we describe in detail the findings of dermatological examinations and measurements of skin pigmentation during this treatment over time and discuss the impact of these changes on patient safety. <b><i>Methods:</i></b> In an investigator-initiated, phase 2, open-label pilot study, 2 patients with loss-of-function POMC gene mutations and 3 patients with loss-of-function variants in LEPR were treated with the MC4R agonist <i>setmelanotide</i>. Dermatological examination, dermoscopy, whole body photographic documentation, and spectrophotometric measurements were performed at screening visit and approximately every 3 months during the course of the study. <b><i>Results:</i></b> We report the results of a maximum treatment duration of 46 months. Skin pigmentation increased in all treated patients, as confirmed by spectrophotometry. During continuous treatment, the current results indicate that elevated tanning intensity levels may stabilize over time. Lips and nevi also darkened. In red-haired study participants, hair color changed to brown after initiation of <i>setmelanotide</i> treatment. <b><i>Discussion:</i></b> <i>Setmelanotide</i> treatment leads to skin tanning and occasionally hair color darkening in both POMC- and LEPR-deficient patients. No malignant skin changes were observed in the patients of this study. However, the results highlight the importance of regular skin examinations before and during MC4R agonist treatment.

scholarly journals The Impact of Nordic Walking on Bone Properties in Postmenopausal Women with Pre-Diabetes and Non-Alcohol Fatty Liver Disease

2021 ◽  
Vol 18 (14) ◽  
pp. 7570
Author(s):  
Xiaming Du ◽  
Chao Zhang ◽  
Xiangqi Zhang ◽  
Zhen Qi ◽  
Sulin Cheng ◽  
...  
Keyword(s):  
Liver Disease ◽  
Fatty Liver ◽  
Postmenopausal Women ◽  
Fatty Liver Disease ◽  
Whole Body ◽  
Nordic Walking ◽  
Significant Group ◽  
Time Interaction ◽  
Bone Properties ◽  
The Impact

This study investigated the impact of Nordic walking on bone properties in postmenopausal women with pre-diabetes and non-alcohol fatty liver disease (NAFLD). A total of 63 eligible women randomly participated in the Nordic walking training (AEx, n = 33), or maintained their daily lifestyle (Con, n = 30) during intervention. Bone mineral content (BMC) and density (BMD) of whole body (WB), total femur (TF), femoral neck (FN), and lumbar spine (L2-4) were assessed by dual-energy X-ray absorptiometry. Serum osteocalcin, pentosidine, receptor activator of nuclear factor kappa-B ligand (RANKL) levels were analyzed by ELISA assay. After an 8.6-month intervention, the AEx group maintained their BMCTF, BMDTF, BMCL2−4, and BMDL2−4, and increased their BMCFN (p = 0.016), while the Con group decreased their BMCTF (p = 0.008), BMDTF (p = 0.001), and BMDL2−4 (p = 0.002). However, no significant group × time interaction was observed, except for BMDL2−4 (p = 0.013). Decreased pentosidine was correlated with increased BMCWB(r = −0.352, p = 0.019). The intervention has no significant effect on osteocalcin and RANKL. Changing of bone mass was associated with changing of pentosidine, but not with osteocalcin and RANKL. Our results suggest that Nordic walking is effective in preventing bone loss among postmenopausal women with pre-diabetes and NAFLD.

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