Graphene-based materials for microstrip patch antenna

Microstrip patch antennas are becoming increasingly relevant because of their advantages such as light weight, low costs, and ease of fabrication. To enhance the performance of an antenna, graphene was included into the fabrication of the microstrip patch antenna. Because of its numerous excellent characteristics, graphene has gained attention in recent years as a leading material. In this research, a microstrip patch antenna based on graphene was fabricated and tested at 5 GHz. The fabrication started with the production of graphene paste and was screen printed onto RT duroid 5880 substrates. To verify the binding between the graphene paste and the substrate, an adhesion test was performed on the finished graphene-based patch antenna using the Scotch tape method. The performance of fabricated antenna was measured using vector network analyzer (VNA) which includes return loss and bandwidth. The findings of the measurements were compared with the simulation results that were generated by the High Frequency Structure Simulator (HFSS). The return loss of the graphene-based antenna was measured to be -17.6314 dB, which is a little bit lower than the simulated value of -18.0597 dB that was generated by the HFSS software. The calculated bandwidth for simulated and fabricated graphene-based patch antenna were found at 156 MHz and 297.4 MHz, respectively. Based on the findings, it can be concluded that the return loss result indicates that the fabricated graphene-based patch antenna agrees well with the simulated patch antenna, although the fabricated patch antenna has a greater bandwidth than the simulated antenna

Graphene-based material for microstrip bandpass filter

Graphene has become one of the most essential materials in recent years due to its numerous advantages and benefits. Because of its features, graphene is becoming more widespread in a variety of applications, particularly in electrical devices. In this research, graphene thick film paste (GTP) has been used to fabricate a microstrip bandpass filter (BPF). To obtain graphene nanoparticle powder, graphene oxide (GO) was synthesized from nanoparticle graphite using the Improved Hummers Method (IHM). The graphene oxide (GO) was chemically reduced to reduced graphene oxide or graphene (rGO) using ascorbic acid as the reducing agent. The structural and morphological properties of three nanoparticle powders, G, GO, and rGO, were investigated. An X-ray Diffractometer (XRD) (Rigaku Miniflex) with a diffraction angle of 10◦ to 60◦ was used to differentiate and determine the structure of crystalline materials. Thermal stability of the samples was identified using thermogravimetric analysis (TGA). The synthesized rGO has been used to fabricate BPF circuit. The obtained nanoparticle rGO was mixed with an organic carrier composed of linseed oil, m-xylene, and α-terpineol to form GTP. The GTP was screen printed on RT duroid 5880 substrates to form BPF circuit. The BPF circuit that was created was tested for paste-to-substrate adhesion. Then, the fabricated BPF circuit was tested using vector network analyzer (VNA) and compared with conventional BPF to obtain scattering parameter results which include return loss, insertion loss, and bandwidth. The graphene BPF circuit demonstrated a good performance with return loss and insertion loss at −27.481 dB and −0.725 dB, respectively, and a bandwidth of 1.5916 GHz while conventional return loss was −26.750 dB and insertion loss value the same as graphene which is −0.725 dB and bandwidth 0.7077 GHz. From the result graphene BPF showed better result than conventional BPF

Structural, morphological and shielding effectiveness properties of Yttrium Iron Garnet/Epoxy composites at X-Band frequency prepared via solid state reaction method

The fast progression of microwave absorption technology has caused electromagnetic interference (EMI) or electromagnetic pollution into a worrying situation. Aside from causing adverse effects on industrial apparatus, EM pollution also carries a threat to human health as well. This problem can be prevented by applying Yttrium Iron Garnet (YIG) from Yttrium (III) oxide, Y2O3 and Iron (II) oxide, Fe2O3 as EM shielding material to lessen the EM pollution and interferences. The YIG samples were prepared using a solid-state reaction method and sintered at 900 °C to obtain a single phase of garnet. An epoxy resin was used as a matrix and mixed with YIG with 0 wt%, 5 wt% and 20 wt% compositions of the fillers. The stretching vibrations of the functional groups were analyzed using Fourier Transform Infrared (FTIR). The X-Ray Diffraction (XRD) analysis at a diffraction angle of 10° to 80° confirmed the presence of YIG phase at 900 °C with the average crystallite size was 49.28 nm calculated using Scherrer calculator in X’pert Highscore software. The morphology was determined by Field Emission Scanning Electron Microscope (FESEM) where it is smoother and more homogeneous embedded in the polymer matrix as the composition increases. A Vector Network Analyzer (VNA) was used to measure the shielding effectiveness and the introduction of the sample with the composition of 20 wt% YIG as the filler showed the increment of shielding effectiveness with 1.91 dB which is 4 times higher compared to pure epoxy at the X-band frequency. The results show that the structure and properties of filler materials strongly influence the shielding effectiveness of the composite

Public Awareness and Practices Towards Self-Medication with Antibiotics Among Malaysian Population: Questionnaire Development and Pilot Testing

Not Availabl

Mapping geographical inequalities in access to drinking water and sanitation facilities in low-income and middle-income countries, 2000–17

Abstract Background: Universal access to safe drinking water and sanitation facilities is an essential human right, recognised in the Sustainable Development Goals as crucial for preventing disease and improving human wellbeing. Comprehensive, high-resolution estimates are important to inform progress towards achieving this goal. We aimed to produce high-resolution geospatial estimates of access to drinking water and sanitation facilities. Methods: We used a Bayesian geostatistical model and data from 600 sources across more than 88 low-income and middle-income countries (LMICs) to estimate access to drinking water and sanitation facilities on continuous continent-wide surfaces from 2000 to 2017, and aggregated results to policy-relevant administrative units. We estimated mutually exclusive and collectively exhaustive subcategories of facilities for drinking water (piped water on or off premises, other improved facilities, unimproved, and surface water) and sanitation facilities (septic or sewer sanitation, other improved, unimproved, and open defecation) with use of ordinal regression. We also estimated the number of diarrhoeal deaths in children younger than 5 years attributed to unsafe facilities and estimated deaths that were averted by increased access to safe facilities in 2017, and analysed geographical inequality in access within LMICs. Findings: Across LMICs, access to both piped water and improved water overall increased between 2000 and 2017, with progress varying spatially. For piped water, the safest water facility type, access increased from 40·0% (95% uncertainty interval [UI] 39·4–40·7) to 50·3% (50·0–50·5), but was lowest in sub-Saharan Africa, where access to piped water was mostly concentrated in urban centres. Access to both sewer or septic sanitation and improved sanitation overall also increased across all LMICs during the study period. For sewer or septic sanitation, access was 46·3% (95% UI 46·1–46·5) in 2017, compared with 28·7% (28·5–29·0) in 2000. Although some units improved access to the safest drinking water or sanitation facilities since 2000, a large absolute number of people continued to not have access in several units with high access to such facilities (>80%) in 2017. More than 253 000 people did not have access to sewer or septic sanitation facilities in the city of Harare, Zimbabwe, despite 88·6% (95% UI 87·2–89·7) access overall. Many units were able to transition from the least safe facilities in 2000 to safe facilities by 2017; for units in which populations primarily practised open defecation in 2000, 686 (95% UI 664–711) of the 1830 (1797–1863) units transitioned to the use of improved sanitation. Geographical disparities in access to improved water across units decreased in 76·1% (95% UI 71·6–80·7) of countries from 2000 to 2017, and in 53·9% (50·6–59·6) of countries for access to improved sanitation, but remained evident subnationally in most countries in 2017. Interpretation: Our estimates, combined with geospatial trends in diarrhoeal burden, identify where efforts to increase access to safe drinking water and sanitation facilities are most needed. By highlighting areas with successful approaches or in need of targeted interventions, our estimates can enable precision public health to effectively progress towards universal access to safe water and sanitation