Detection

Journal Information
ISSN / EISSN: 23312076 / 23312084
Total articles ≅ 34

Latest articles in this journal

Daniel Nelson Russell
Published: 1 January 2023
Journal: Detection
Detection, Volume 10, pp 1-6; https://doi.org/10.4236/detection.2023.101001

Abstract:
Preferably 20 ppm anhydrous ammonia (NH3) is proposed to be added to hydrogen fuel (H) made from renewable energy sources (green hydrogen), so that H leaks may be easily detectable by smell, but not dangerously toxic. Including this odor agent, would allow H to be distributed safely in pipes, as required by law, and it would allow H to be safely stored, transported, and exported for sale, and widely commercialized. Further research is suggested to identify optimum pressure, temperature, and automated technique for injecting NH3 into H, and to chart the minimum concentration needed, as a function of temperature and humidity. An application to make hypersonic H burning aircraft safer for ground maintenance crews is proposed. An ability to make, store and distribute H, made from local sources of renewable energy, would reduce a need for fossil fuels, especially in poor, remote communities, where it could improve their economy by creating an export product for sale, while reducing pollution.
Sylvester Obum Anyikwa, Obineche Charles Ndukwe, Theresa Chinwendu Umeojiakor, Pat Chukwudi Nnaji, Ndidiamaka Martina Amadi
Published: 1 January 2022
Journal: Detection
Detection, Volume 09, pp 37-49; https://doi.org/10.4236/detection.2022.94004

Abstract:
The work of “Monitoring and Evaluation of Air Pollution” the main aim of this work is to measure the concentrations of gases which include CO2, CO, NOx, SOx and thermal radiation and carry out an analysis of the measured data. This experiment was scheduled to take place at Egbema flow station which is managed by NPDC (Nigerian Petroleum Development Commission) Shell location 2 in Obiakpu, Ohaji Imo state. The bad effects of these pollutant gases on the community can include cause of diseases to plants and animals, causes of physical ailments in the respiratory tract of humans, and death and degradation of the surrounding environment. The parameters measured during this exercise include the distance from the flow station, latitude and longitude of the distance measured on the earth’s surface, time for the experiment and the concentration of pollutant gases. The instrument used includes CO meter, CO2 meter, SOx and NOx meters, and thermal radiation meter. The gases were measured in three different time intervals between 10:50 am - 11:23 am (for CO: 0.02 ppm, 0.01 ppm, 0 ppm, 0 ppm, 0.01 ppm, 0 ppm; for CO2: 0.04 ppm, 0.01 ppm, 0.01 ppm, 0.02 ppm, 0.01 ppm, 0 ppm; for SOx: 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3; for NOx: 0.127 mg/m3, 0.098 mg/m3, 0.12 mg/m3, 0.122 mg/m3, 0.113 mg/m3, 0.103 mg/m3; for thermal radiation: 57.4 W/m2, 61.5 W/m2, 65.1 W/m2, 64.9 W/m2, 81.9 W/m2, 148.3 W/m2), 1:30 pm - 2:13 pm (for CO: 0.01 ppm, 0.02 ppm, 0 ppm, 0 ppm, 0.1 ppm, 0 ppm; for CO2: 0.01 ppm, 0.01 ppm, 0.01 ppm, 0.01 ppm, 0 ppm, 0 ppm; for SOx: 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3; for NOx: 0.122 mg/m3, 0.117 mg/m3, 0.114 mg/m3, 0.115 mg/m3, 0.122 mg/m3, 0.11 mg/m3; for thermal radiation: 120.5 W/m2, 132.8 W/m2, 156.7 W/m2, 170.5 W/m2, 148.5 W/m2, 95.1 W/m2) and 5 pm - 5:37 pm (for CO: 0.02 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0 ppm, 0 ppm; for CO2: 0.03 ppm, 0.2 ppm, 0.1 ppm, 0.1 ppm, 0 ppm, 0.1 ppm; for SOx: 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3, 0 mg/m3; for NOx: 0.128 mg/m3, 0.118 mg/m3, 0.119 mg/m3, 0.117 mg/m3, 0.124 mg/m3, 0.114 mg/m3; for thermal radiation: 121.4 W/m2, 133.3 W/m2, 160.2 W/m2, 177 W/m2, 161.4 W/m2, 97.2 W/m2) at distances of 0 m, 100 m, 300 m, 500 m, 1000 m and 1500 m respectively. From the values gotten from the gas concentration measurements, we can say that SOx gases are either minute or not available in the environment. Also, from the graph analysis carried out on the gases, we can also say that CO2 concentration is either increasing or at the same level throughout the distance while the concentrations of NOx, CO and thermal radiation reduce with increasing distance. On the part of the “averaging time model” used in the analysis, we can say that at increasing averaging times the concentration of gases reduces. Analysis of whether the environment is polluted and with which gas exactly is also carried out using the Air quality index and it was deduced that the environment is polluted with NOx gases because the concentration is above the normal environmental ambient temperature.
Rafika Mejri, Taoufik Aguili
Published: 1 January 2022
Journal: Detection
Detection, Volume 09, pp 29-36; https://doi.org/10.4236/detection.2022.93003

Abstract:
We are interested in this work to electromagnetic leakage, for example the door of the microwave oven (or shielding of electronic functions working in the microwave band containing holes for ventilation circuit) which must be transparent (chain link) but the level of electromagnetic leakage issued by this device must not exceed certain standards. This work started with this article in which we are interested in a simple structure consisting of a multilayer structure incorporating a radiating aperture. We show in this paper mainly the interests of this study and the limitations of using these structures. Modeling of this device is provided by the wave concept iterative procedure (WCIP) which is simple to implement and is characterized by the fast execution method. The validation of our work is carried out by comparing our results with those calculated by the Ansoft HFSS software which shows a good agreement.
Cuixian Zhang
Published: 1 January 2022
Journal: Detection
Detection, Volume 09, pp 13-27; https://doi.org/10.4236/detection.2022.92002

Abstract:
Just as lead-based perovskites that are hot in solar cell preparation, Bi-based perovskites have demonstrated excellent performance in direct X-ray detection, especially the Cs3Bi2I9 single crystals (SCs). However, compared with lead-halide perovskites, one challenge for the Cs3Bi2I9 SCs for X-ray detection application is that it is difficult to prepare large-sized and high-quality SCs. Therefore, how to get a large area with a high-quality wafer is also as important as Cs3Bi2I9 growth method research. Here, different anti-solvents are used for the preparation of poly-crystalline powder with the Antisolvents precipitation (A) method, as a control, High-energy ball milling (B) was also used to prepare poly-crystalline powders. The resultant two types of Cs3Bi2I9 wafer exhibit a micro-strain of 1.21 × 10-3, a resistivity of 5.13 × 108 Ω cm and a microstrain of 1.21 × 10-3, a resistivity of 2.21 × 109 Ω cm. As a result, an X-ray detector based on the high-quality Cs3Bi2I9 wafer exhibits excellent dose rate linearity, a sensitivity of 588 μC·Gyairs-1·cm-2 and a limit of detection (LoD) of 76 nGyair·s-1.
Weiwei Huang, Yanan Hu, Jinjun Zhu, ZeNan Cen, Jiali Bao
Published: 1 January 2022
Journal: Detection
Detection, Volume 09, pp 1-11; https://doi.org/10.4236/detection.2022.91001

Abstract:
In order to evaluate the electromagnetic environment of 5G base station, measurement and evaluation of the electromagnetic environment are studied. The 12 measuring points are chosen on the roof, inside and outside of the building, which has a 5G base station on the top. The electric field intensity, magnetic field intensity, and power density have been measured. The measurement methods include background measurement and work measurement. Background measurement is the measurement of environmental electromagnetic field (EMF) before the installation of 5G base station while the working measurement is the measurement after the installation of 5G base station. The evaluation methods include t-test for qualitative evaluation and electromagnetic gain for quantitative evaluation. The results show that the electromagnetic environment after the installation of 5G base station in most places is different from that in the background. And the environmental electromagnetic fields in certain parts are lower than those in the background. The conclusions are as follows: 1) The electromagnetic environment of 5G base station is far lower than the control limit of the national standard and conforms to the national standard; 2) The electromagnetic environment of 5G base station has little impact on the electromagnetic environment; 3) It is not sufficient to assume that 5G is harmful to health without the results of the epidemiological investigation; 4) Before the construction of 5G base station, do background EMF detection, which can provide support for future evaluation.
Dabo S. I. Agba, Koudou Djagouri, Bogbe D. L. H. Gogon, Aka A. Koua
Published: 1 January 2021
Journal: Detection
Detection, Volume 08, pp 1-8; https://doi.org/10.4236/detection.2021.81001

Abstract:
In this study, we used strippable LR 115 type 2 which is a Solid State Nuclear Track Detector (SSNTD) widely known for radon gas detection and measurement. The removed thickness of the active layer of samples of this SSNTD, were determined by measuring the average initial thickness (before etching) and residual thickness after 80 to 135 minutes chemical etching in the standard conditions, using an electronic comparator. These results allowed the calculation of the bulk etch rate of this detector in a simple way. The mean value obtained is (3.21 ± 0.21) μm/h. This value is in close agreement with those reported by different authors. It is an important parameter for alpha track counting on the sensitive surface of this polymeric detector after chemical etching because track density depends extremely on its removed layer. This SSNTD was then used for environmental radon gas monitoring in Côte d’Ivoire.
Jamiu Idowu Lawal
Published: 1 January 2019
Journal: Detection
Detection, Volume 07, pp 1-15; https://doi.org/10.4236/detection.2019.71001

Abstract:
Natural radionuclides content in granite from eight functional quarries in Osun State, Southwestern Nigeria was assessed. Eighty granite samples comprise ¾ inches. ½ inch and stone-dust were collected from Wolid, Slava, Ayofe, Espro, Ife/Modakeke, Krystal Vountein, Clario and Omidiran quarries in the State. Measurement was done using a high purity germanium (HPGe) detector. The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) software to determine if granite size has an impact on the activity concentrations. The results revealed that the mean activity concentrations of 238U (12.64 ± 1.89 Bq·kg -1) and 232Th (16.93 ± 2.46 Bq·kg -1) were highest in ¾ inch granite and lowest in stone-dust (5.01 ± 0.77 and 8.97 ± 1.37 Bq·kg -1 respectively), whereas 40K is highest in the ¾ inches (266.19 ± 35.53 Bq·kg -1) and lowest in ½ inches (151.85 ± 25.09 Bq·kg -1) granite. Espro has the highest (23.75 ± 3.74 Bq·kg -1) while Wolid has the lowest (4.11 ± 0.73 Bq·kg -1) 238U activity concentration and Slava has lowest for 232Th (8.21 ± 1.12 Bq·kg -1) and 40K (109.54 ± 11.06 Bq·kg -1). The radiological hazard parameters such as absorbed dose, annual effective dose radium equivalent, gamma index, external index, and internal index, were calculated to assess the radiation hazards associated with granite samples. The results obtained are lower than the recommended limits. The results were compared with the published data of other countries. Although, all the calculated radiation hazard indices were lower than the permissible limits. Therefore, people working in the quarries, granite end-users and the general public are safe from radiological health risks from the quarries, since there is no significant health hazard. The research will give reliable information on activity concentrations of natural radionuclides in granite rocks, contribute to a better understanding of radioactivity distribution in granite, and develop standards.
Xinghua Shi, Quang Phan, , Lance L. McDowell, Jijun Qiu, Zhihua Cai,
Published: 1 January 2018
Journal: Detection
Detection, Volume 06, pp 1-16; https://doi.org/10.4236/detection.2018.61001

Abstract:
This paper provides a theoretical study and calculation of the specific detectivity-D* limit of photovoltaic (PV) mid-wave infrared (MWIR) PbSe n+-p junction detectors operating at both room temperature and TE-cooled temperature. For a typical PbSe p-type doping concentration of 2 × 1017 cm-3 and with high quantum efficiency, the D* limits of a photovoltaic PbSe n+-p junction detector are shown to be 2.8 × 1010 HZ1/2/W and 3.7 × 1010 HZ1/2/W at 300 K and 240 K, with cut-off wavelength of 4.5 μm and 5.0 μm, respectively. It is almost one magnitude higher than the current practical MWIR PV detector. Above 244 K, the detector is Johnson noise limited, and below 191 K the detector reaches background limited infrared photodetector (BLIP) D*. With optimization of carrier concentration, D* and BLIP temperature could be further increased.
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