Effects of hand on EM absorption and antenna performances for internal handset PIFA

Cilj ovog istraživanja je analizirati učinke ruke na elektromagnetsku (EM) apsorpciju i funkcioniranje antene. U radu se procjenjuje EM apsorpcija pomoću specifične brzine apsorpcije - specific absorption rate (SAR) u ljudskoj glavi i ukupne apsorbirane snage od strane korisnika. U radu se razmatraju parametri djelovanja antene uključujući učinkovitost zračenja, ukupnu učinkovitost, pojačanje i širinu frekvencijskog područja. Analiza je provedena pomoću mobilnog telefona položenog na obraz i s nagibom na obraz. Glavni dio istraživanja temelji se na finite-difference time-domain (FDTD) metodi. Rezultati pokazuju da su se SAR vrijednosti smanjile i da se ukupna snaga koju je korisnik apsorbirao brzo povećala zbog umetanja ručnog modela. Ruka korisnika također dovodi do znatnog smanjenja komunikacijskog učinka antene. Osim toga, predstavljena analiza daje neke korisne naznake za dizajn antene mobilnog telefona s obzirom na položaj ruke.The aim of this investigation is to analyse the effects of hand on electromagnetic (EM) absorption and antenna performances. The EM absorption is evaluated by using the specific absorption rate (SAR) in the human head and total absorbed power by the user in this paper. The antenna performance’s parameters comprising radiation efficiency, total efficiency, gain and bandwidth are considered in this investigation. The analysis was performed using mobile phone with a human head and hand model in both cheek and tilt positions. The main part of the investigation is based on the finite-difference time-domain (FDTD) method. The results show that the SAR values are decreased and total absorbed power by user increased rapidly due to insertion of hand model. The user’s hand also leads to degrade antenna’s communication performance considerably. Moreover, the presented analysis provides some useful indication to design handset antenna considering hand effects

Effects of hand on EM absorption and antenna performances for internal handset PIFA

Cilj ovog istraživanja je analizirati učinke ruke na elektromagnetsku (EM) apsorpciju i funkcioniranje antene. U radu se procjenjuje EM apsorpcija pomoću specifične brzine apsorpcije - specific absorption rate (SAR) u ljudskoj glavi i ukupne apsorbirane snage od strane korisnika. U radu se razmatraju parametri djelovanja antene uključujući učinkovitost zračenja, ukupnu učinkovitost, pojačanje i širinu frekvencijskog područja. Analiza je provedena pomoću mobilnog telefona položenog na obraz i s nagibom na obraz. Glavni dio istraživanja temelji se na finite-difference time-domain (FDTD) metodi. Rezultati pokazuju da su se SAR vrijednosti smanjile i da se ukupna snaga koju je korisnik apsorbirao brzo povećala zbog umetanja ručnog modela. Ruka korisnika također dovodi do znatnog smanjenja komunikacijskog učinka antene. Osim toga, predstavljena analiza daje neke korisne naznake za dizajn antene mobilnog telefona s obzirom na položaj ruke.The aim of this investigation is to analyse the effects of hand on electromagnetic (EM) absorption and antenna performances. The EM absorption is evaluated by using the specific absorption rate (SAR) in the human head and total absorbed power by the user in this paper. The antenna performance’s parameters comprising radiation efficiency, total efficiency, gain and bandwidth are considered in this investigation. The analysis was performed using mobile phone with a human head and hand model in both cheek and tilt positions. The main part of the investigation is based on the finite-difference time-domain (FDTD) method. The results show that the SAR values are decreased and total absorbed power by user increased rapidly due to insertion of hand model. The user’s hand also leads to degrade antenna’s communication performance considerably. Moreover, the presented analysis provides some useful indication to design handset antenna considering hand effects

A Double Inverted F-Shape Patch Antenna for Dual-Band Operation

A double inverted F-shape patch antenna is presented for dual-band operation. The proposed antenna is comprised of circular and rectangular slots on a printed circuit board of 40 mm × 40 mm × 1.6 mm with a 50 Ω microstrip transmission line. Commercially available high frequency structural simulator (HFSS) based on the finite element method (FEM) has been adopted in this investigation. It has a measured impedance bandwidths (2 : 1 VSWR) of 18.53% on the lower band and 7.8% on the upper band, respectively. It has achieved stable radiation efficiencies of 79.76% and 80.36% with average gains of 7.82 dBi and 5.66 dBi in the operating frequency bands. Moreover, numerical simulations have been indicated as an important uniformity with measured results

A Compact 5.5 GHz Band-Rejected UWB Antenna Using Complementary Split Ring Resonators

A band-removal property employing microwave frequencies using complementary split ring resonators (CSRRs) is applied to design a compact UWB antenna wishing for the rejection of some frequency band, which is meanwhile exercised by the existing wireless applications. The reported antenna comprises optimization of a circular radiating patch, in which slotted complementary SRRs are implanted. It is printed on low dielectric FR4 substrate material fed by a partial ground plane and a microstrip line. Validated results exhibit that the reported antenna shows a wide bandwidth covering from 3.45 to more than 12 GHz, with a compact dimension of 22 × 26 mm2, and VSWR < 2, observing band elimination of 5.5 GHz WLAN band

Estimation of the SARS-CoV-2 specific reproduction number in SAARC countries: A 60-days Data-driven analysis

Novel coronavirus disease-2019 (COVID-19) was acknowledged as a global pandemic by WHO, which was first observed at the end of December 2019 in Wuhan city, China, caused by extreme acute respiratory syndrome coronavirus2 (SARS-CoV-2). According to the Weekly operation Update on COVID-19 (November 13, 2020) of the World Health Organization, more than 53 million confirmed cases are reported, including 1.3 million deaths. Various precautionary measures have been taken worldwide to reduce its transmission, and extensive researches are going on. The purpose of this analysis was to determine the initial number of reproductions (Ro) of the coronavirus of SAARC countries named Afghanistan, Bangladesh, India, Pakistan, Bhutan, Nepal, the Maldives, and Sri-Lanka for the first 60 days as the growth is exponential in the early 60 days. The reproduction numbers of coronavirus for Afghanistan, Bangladesh, India, Pakistan, Bhutan, the Maldives, Nepal, and Sri Lanka are 1.47, 3.86, 2.07, 1.43, 1.31, 3.22, 1.75, and 2.39 respectively. The basic reproduction number (R0) 3.86 for Bangladesh and 1.31 for Bhutan indicated that up to 60-days of the outbreak COVID-19, the epidemic was more severe in Bangladesh and less severe in Bhutan among all the SAARC countries. Our predictions can be helpful in planning alertness and taking the appropriate measures to monitor it

Development of a robust multi-scale featured local binary pattern for improved facial expression recognition

Compelling facial expression recognition (FER) processes have been utilized in very successful fields like computer vision, robotics, artificial intelligence, and dynamic texture recognition. However, the FER’s critical problem with traditional local binary pattern (LBP) is the loss of neighboring pixels related to different scales that can affect the texture of facial images. To overcome such limitations, this study describes a new extended LBP method to extract feature vectors from images, detecting each image from facial expressions. The proposed method is based on the bitwise AND operation of two rotational kernels applied on LBP(8,1)and LBP(8,2)and utilizes two accessible datasets. Firstly, the facial parts are detected and the essential components of a face are observed, such as eyes, nose, and lips. The portion of the face is then cropped to reduce the dimensions and an unsharp masking kernel is applied to sharpen the image. The filtered images then go through the feature extraction method and wait for the classification process. Four machine learning classifiers were used to verify the proposed method. This study shows that the proposed multi-scale featured local binary pattern (MSFLBP), together with Support Vector Machine (SVM), outperformed the recent LBP-based state-of-the-art approaches resulting in an accuracy of 99.12% for the Extended Cohn–Kanade(CK+) dataset and 89.08% for the Karolinska Directed Emotional Faces(KDEF)dataset

Modeling on population growth and its adaptation: A comparative analysis between Bangladesh and India

The biggest challenge in the world is population growth and determining how society and the state adapt to it as it directly affects the fundamental human rights such as food, clothing, housing, education, medical care, etc. The population estimates of any country play an important role in making the right decision about socio-economic and population development projects. Unpredictable population growth can be a curse. The purpose of this research article is to compare the accuracy process and proximity of three mathematical model such as Malthusian or exponential growth model, Logistic growth model and Least Square model to make predictions about the population growth of Bangladesh and India at the end of 21st century. Based on the results, it has been observed that the population is expected to be 429.32(in million) in Bangladesh and 3768.53 (in million) in India by exponential model, 211.70(in million) in Bangladesh and 1712.94(in million) in India by logistic model and 309.28 (in million) in Bangladesh and 2686.30 (in million) in India by least square method at the end of 2100. It was found that the projection data from 2000 to 2020 using the Logistic Growth Model was very close to the actual data. From that point of view, it can be predicted that the population will be 212 million in Bangladesh and 1713 million in India at the end of the 21st century. Although transgender people are recognized as the third sex but their accurate statistics data is not available. The work also provides a comparative scenario of how the state has adapted to the growing population in the past and how they will adapt in the future

Enhancement of the shielding capability of soda–lime glasses with sb2o3 dopant: A potential material for radiation safety in nuclear installations

Elastic moduli were theoretically computed using the Makishima–Mackenzie model for SiO2–Na2O–CaO glasses doped with Sb2O3 contents. The calculated elastic moduli (Young’s, bulk, shear, and longitudinal modulus) were observed to increase with an increase in the Sb2O3 contents. The micro hardness showed an increase, while Poisson’s ratio decreased with the rise of the Sb2O3 contents. In addition, gamma-ray and neutron shielding parameters were evaluated for the investigated glasses. The linear attenuation coefficient (LAC) was simulated using the Monte Carlo N particle transport code (MCNP-5). Other parameters, such as the mass attenuation coefficient (MAC), transmission factor (TF), and half-value layer, were calculated based on the simulated LAC. The addition of Sb2O3 content was observed to enhance the investigated glasses’ shielding parameters, where the highest LAC was achieved for the SCNSb10 glass with 10 mol% Sb2O3 and decreased from 0.441 to 0.154 cm-1 at gamma energies between 0.248 and 1.406 MeV. Furthermore, the fast neutron effective removal cross-section (ΣR) was computed theoretically. The calculated results showed that the highest ΣR was equal to 0.0341 cm2g-1 and was obtained for the SCNSb0 glass, which had no Sb2O3 content, while the lowest ΣRwas equal to 0.0286 cm2 g-1 for the SCNSb10 glass sample. The present work was carried out to examine the advantages of the soda–lime glasses with different Sb2O3 contents in several photon shielding applications, especially for radiation safety in nuclear installations. © 2020 by the authors.This work was funded by the Research Universiti Grant, Universiti Kebangsaan Malaysia, Geran Universiti Penyelidikan (GUP), code: 2018-133, and the APC was funded by code: 2018-133

Evaluation of radiation shielding features of co and ni-based superalloys using mcnp-5 code: Potential use in nuclear safety

Due to their excellent heat resistance, superalloys are used predominantly in the manufacturing of engine parts and accessories for aircraft and aerospace equipment. The Monte Carlo simulation (MCNP-5) code was performed to estimate the mean track length of the incident photons inside six different alloys. Then, based on the simulated track length, other important γ-ray shielding parameters were calculated. In this study, the highest mass attenuation coefficient was obtained for alloys encoded MAR-302 and MAR-247 and varied in the range 0.035–72.94 and 0.035–71.98 cm2·g−1, respectively. The lowest mass attenuation coefficient was found for alloys coded Inconel-718 and Nimocast-75 with a range of 0.033–59.25 and 0.32–59.30 cm2·g−1, respectively. Use was made of a recently developed online program Phy-X/PD to calculate the effective atomic number, equivalent atomic number, and the buildup factors for the alloys of interest. The effective removal cross-section for the fast neutron was also calculated for the studied alloys: the highest value was found for the alloys coded with Inconel-718 (∑R = 0.01945 cm2·g−1) and Nimocast-75 (∑R = 0.01940 cm2·g−1), and the lowest value was obtained for alloy coded MAR-302 (∑R = 0.01841 cm2·g−1). Calculated data indicate that MAR-302 and MAR-247 are superior candidates for shielding of gamma-rays, while Inconel-718 and Nimocast-75 MAR-302 are suitable for the shielding of fast neutrons. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.This work was funded by the Research Universiti Grant, Universiti Kebangsaan Malaysia, Geran Universiti Penyelidikan (GUP), code: 2018-134

Effects of Radiation sterilization Dose on the Molecular Weight and Gelling Properties of Commercial Alginate Samples

From Frontiers via Jisc Publications RouterHistory: collection 2021, received 2021-08-20, accepted 2021-11-12, epub 2021-12-20Publication status: PublishedTo estimate the molecular weight (Mw) and gelling properties, a total of 26 alginate samples consisting of control (n = 13) and 15 kGy γ-irradiated (n = 13) samples were characterized through viscometric and gel permeation chromatography (GPC-MALLS) methods. Based on the observations, a remarkable decrease in the intrinsic viscosity of all samples of alginates was evident due to the effects of radiation, with a linear relationship between viscosity and concentration in 0.01 M NaCl solution. The correlation among the Mw, percentage mass recovery, radii of gyration (Rz/Rg), and percentage reduction of Mw assessed by GPC was significant. The Mw decreased dramatically (from 3.1 × 105 to 0.49 × 105 mole/g in sample no. 12) by the effect of radiation with momentous relation to the % reduction of the molecular weight. The highest molecular weight reduction (84%), which is the most sensitive to γ-radiation, and the average reduction rate was ≥50%. The mass recovery was 100% obtained from samples no. 1,3,4,5,7,12, and 13, while the rest of the samples’ recovery rate was significantly higher. The reduction rate of mass molecular weight (Mw) is higher than the average molecular weight (Mv), but they showed a sensitivity towards radiation, consequently their performance are different from each other. The stability test was performed as a critical behaviour in the control, recurrently same as in the irradiated samples. Thus, the sterilization dose of 15 kGy for the Mw distribution, and subsequently for the characterization, was significantly effective