Effect of GNWs/NiO-WO3/GNWs Heterostructure for NO2 Gas Sensing at Room Temperature

Recently, as air pollution and particulate matter worsen, the importance of a platform that can monitor the air environment is emerging. Especially, among air pollutants, nitrogen dioxide (NO2) is a toxic gas that can not only generate secondary particulate matter, but can also derive numerous toxic gases. To detect such NO2 gas at low concentration, we fabricated a GNWs/NiO-WO3/GNWs heterostructure-based gas sensor using microwave plasma-enhanced chemical vapor deposition (MPECVD) and sputter, and we confirmed the NO2 detection characteristics between 10 and 50 ppm at room temperature. The morphology and carbon lattice characteristics of the sensing layer were investigated using field emission scanning electron microscopy (FESEM) and Raman spectroscopy. In the gas detection measurement, the resistance negative change according to the NO2 gas concentration was recorded. Moreover, it reacted even at low concentrations such as 5–7 ppm, and showed excellent recovery characteristics of more than 98%. Furthermore, it also showed a change in which the reactivity decreased with respect to humidity of 33% and 66%.

Algorithms with Area under the Curve for Daily Urinary Estrone-3-Glucuronide and Pregnanediol-3-Glucuronide to Signal the Transition to the Luteal Phase

Background and Objectives: Home fertility assessment methods (FAMs) for natural family planning (NFP) have technically evolved with the objective metrics of urinary luteinizing hormone (LH), estrone-3-glucuronide (E3G) and pregnanediol-3-glucuronide (PDG). Practical and reliable algorithms for timing the phase of cycle based upon E3G and PDG levels are mostly unpublished and still lacking. Materials and Methods: A novel formulation to signal the transition to the luteal phase was discovered, tested, and developed with a data set of daily E3G and PDG levels from 25 women, 78 cycles, indexed to putative ovulation (day after the urinary LH surge), Day 0. The algorithm is based upon a daily relative progressive change in the ratio, E3G-AUC/PDG-AUC, where E3G-AUC and PDG-AUC are the area under the curve for E3G and PDG, respectively. To improve accuracy the algorithm incorporated a three-fold cycle-specific increase of PDG. Results: An extended negative change in E3G-AUC/PDG-AUC of at least nine consecutive days provided a strong signal for timing the luteal phase. The algorithm correctly identified the luteal transition interval in 78/78 cycles and predicted the start day of the safe period as: Day + 2 in 10/78 cycles, Day + 3 in 21/78 cycles, Day + 4 in 28/78 cycles, Day + 5 in 15/78 cycles, and Day + 6 in 4/78 cycles. The mean number of safe luteal days with this algorithm was 10.3 ± 1.3 (SD). Conclusions: An algorithm based upon the ratio of the area under the curve for daily E3G and PDG levels along with a relative PDG increase offers another approach to time the phase of cycle. This may have applications for NFP/FAMs and clinical evaluation of ovarian function.

CHANGES IN LEVELS OF MAIZE PRODUCTIVITY IN HIMACHAL PRADESH: 1990-91 TO 2014-15

The chief objective of the present study is to reveal spatial patterns of maize productivity and Changes in Himachal Pradesh during 1990-91 to 2014-15. For achieving this purpose, the study is divided into three parts. First part deals with spatial patterns of maize productivity. It is found that the index value of maize productivity varied from minimum of 47.55 percent in Spiti tehsil to 155.90 percent in Churah tehsil in 1990-91. While in 2002-03, it varied from 47.45 percent in Lahaul tehsil to 143.14 percent in Churah tehsil. Whereas in 2014-15, it is lowest of 47.97 percent in Spiti tehsil and highest of 141.51 percent in Churah tehsil. It is also observed that in all time periods, magnitude of maize productivity starts declining from west to east. In second part, it is found that in Himachal Pradesh, the highest index value of maize productivity has declined from 150.90 percent to 141.15 percent during 1990-91 to 2014-15 and registered overall negative change of 8.39 percent index value. Whereas the lowest index value of maize productivity has increased from 47.55 percent in 1990-91 to 47.97 percent in 2014-15 and experience 0.42 percent increase in lowest index value of maize productivity during study period, thus the gap between high and low magnitude of maize productivity has minimized which shows that sign of healthy maize cultivation. In third part, major problems are identified and suggestions are made to solve these problems for increasing the maize productivity in the state. The present study is empirical in nature and based on secondary sources of data. Three time periods are taken and averages are derived for each time period, because 1990-91 is the year of liberalization era and 2002-03 and 2014-15 are post liberalization period. Singh (1976), technique is used for deriving the results and choropleth method is applied for mapping the results.

Dilatometry of Steel for the Production of 5.56 mm Calibre Rifle Barrels

During high rates of fire, the bore of the firearm barrel is exposed to high temperatures. This exposure induces structural changes in the barrel material, which is especially significant for the substrate of the galvanic chrome plating. The alloy steel grades used currently for firearm barrels, when exposed to heating above the ferrite stability limits, develop a phase transition with a discrete negative change in the material volume, which results in typical crazing in the bore. This effect is destructive to the galvanic chrome plating, leading to a loss of adhesion, which reduces the ballistic performance of the firearm, especially its muzzle velocity. This can be prevented by manufacturing barrels from steels having a limited range of phase transitions. The primary method for determining the presence of distinct volume changes in steel due to phase transition is dilatometry over a wide temperature range, which includes the interval within which the barrel bore is heated. This paper presents the dilatometry results for four steel grades, which included a steel grade currently used for firearm barrels, and an analysis of the effects of phase transition on the degradation of the barrel bore.

Temperature dependence of Raman shift in defective single-walled carbon nanotubes

Raman scatterings of both pristine and defective single-walled carbon nanotubes were measured. Defects on carbon nanotubes (CNTs) were induced by UV/O3 treatment, and the correlation between the temperature dependence of the Raman shift of the G-band and the crystallinity of CNTs was investigated. In the temperature range of 250–600 K, a gradual negative change in the slope was observed; the linear shift of the Raman G-band frequency with respect to temperature increased as the crystallinity deteriorated. This phenomenon is attributed to the increase in the fourth-order phonon-phonon scattering interaction resulting from the induced defects.

In situ regulation of microstructure and microwave-absorbing properties of FeSiAl through HNO3 oxidation

Wrapping insulation of coatings is effective for enhancing the microwave-absorbing properties (MAPs) of ferromagnetic absorbents (FMAs). However, the process is still limited by the low bonding strength with the matrix. Herein, an in situ regulation strategy based on the preparation of thin thickness and strong adhesion insulating layers through HNO3 oxidation was developed to address the limitations. The oxidation process of FeSiAl (FSA) powders was carried out by HNO3 following three main steps. First, the original oxide layer first reacted with HNO3 to form Fe3+ and Al3+. Second, the oxide layer composed of Al2O3 and Fe3O4 was preferentially formed due to the negative change in Gibbs free energy. Finally, the oxide and pigment-deposition layers were subjected to competitive growth and dissolution accompanied by the dissolution of Fe and Al atoms. Oxidation time up to 10 min resulted in the formation of a bilayer structure with a thickness of ∼50 nm on the FSA surface, as well as an outer layer crammed of Al(OH)3 and Fe(OH)3, and an inner layer containing mixed Fe2O3, Fe3O4, Al2O3, and SiO2. The MAPs of as-treated FSA achieved minimum reflection loss (RL) of −25.90 dB at 13.36 GHz, as well as absorption bandwidth of 5.61 GHz (RL < −10 dB) at 10.13–15.74 GHz and thickness of 2.5 mm. In sum, the developed route looks promising for the preparation of high-performance FMAs.

Adhesive and Magnetic Properties of Polyvinyl Butyral Composites with Embedded Metallic Nanoparticles

Magnetic metallic nanoparticles (MNPs) of Ni, Ni82Fe18, Ni50Fe50, Ni64Fe36, and Fe were prepared by the technique of the electrical explosion of metal wire. The average size of the MNPs of all types was in the interval of 50 to 100 nm. Magnetic polymeric composites based on polyvinyl butyral with embedded metal MNPs were synthesized and their structural, adhesive, and magnetic properties were comparatively analyzed. The interaction of polyvinyl butyral (supplied as commercial GE cryogenic varnish) with metal MNPs was studied by microcalorimetry. The enthalpy of adhesion was also evaluated. The positive values of the enthalpy of interaction with GE increase in the series Ni82Fe18, Ni64Fe36, Ni50Fe50, and Fe. Interaction of Ni MNPs with GE polymer showed the negative change in the enthalpy. No interfacial adhesion of GE polymer to the surface of Fe and permalloy MNPs in composites was observed. The enthalpy of interaction with GE polymer was close to zero for Ni95Fe5 composite. Structural characterization of the GE/Ni composites with the MNPs with the lowest saturation magnetization confirmed that they tended to be aggregated even for the materials with lowest MNPs concentrations due to magnetic interaction between permalloy MNPs. In the case of GE composites with Ni MNPs, a favorable adhesion of GE polymer to the surface of MNPs was observed.

Vegetation Change Detection in the Niger Delta Region of Nigeria using Remote Sensing and GIS Techniques from 2000 to 2020

Generally, vegetation change through the conversion of the world’s forest land to other uses has assumed an increasing scale due to the unprecedented growth of the human population which increases the demand for food and land. Some believed that decrease in vegetation in the area is attributed to oil exploration and exploitation activities only. This study aimed to find out the nature of the vegetation change in the region from 2000 to 2020. The data used was remotely sensed images as Enhanced Vegetation Index (EVI) observed by Terra-MODIS, downloaded via United States Geological Survey (USGS). The Simple Image Differencing was performed on two images (February 18, 2000 and February 18, 2020) using IDRISI software. The result shows that all the states in the Niger Delta region experience both positive and negative change in vegetation cover. The positive change was observed around locations where agricultural plantations exists and within urban areas followed by oil and gas exploration and exploitation that damage the natural forest cover, while negative change was observed around farms where intensive rainy season farming takes place. It was recommended that deforested areas in the region should be reclaimed by planting economic trees as plantation to enhance greenness and maintain balance of the ecosystem. If intensive farming is necessary, it should be practiced sustainably to save the environment.

Disruptiveness of COVID-19: Differences in Course Engagement, Self-appraisal, and Learning

We investigated how the transition to remote instruction amidst the COVID-19 pandemic affected students’ engagement, self-appraisals, and learning in advanced placement (AP) Statistics courses. Participants included 681 (Mage=16.7 years, SDage=.90; %female=55.4) students enrolled in the course during 2017-2018 (N=266), 2018-2019 (N=200), and the pandemic-affected 2019-2020 (N=215) year. Students enrolled during the pandemic-affected year reported a greater improvement in affective engagement but a decrease in cognitive engagement in the spring semester relative to a previous year. Females enrolled in the pandemic-affected year experienced a greater negative change in affective and behavioral engagement. Students enrolled during the pandemic-affected year reported a greater decrease in their anticipated AP exam scores and received lower scores on a practice exam aligned with the AP exam compared to a prior year. Though resilient in some respects, students’ self-appraisal and learning appeared negatively affected by pandemic circumstances.

Research on Multi-Agent Systems in a Smart Small Grid for Resource Apportionment and Planning

With the advancement in the technology, deployment of sensors in the industrial or public building is increasing rapidly. The basic aim is to obtain the data from the environment and decision making to the energy saving. The activities caused by the human results the undergoing negative change in the environment. There are many techniques available for decision making and consider the environmental factors solely which cause the energy consumption. However, user’s preferences are not adapted by the systems, but at energy consumption optimization, these systems are very successful. The end-users use the system which considers the factors and their wellbeing are get affected. The distributed generation is incorporated by the Smart Small Grid (SSG), communication network and the sensors for the more reliable, flexible and efficient grid. The energy saving system is presented in this paper which also adapts to the inhabitants preferences apart from environmental conditions consideration. The architecture of Multi-Agent System (MAS) and the agents are utilized for negotiation process performance between the users comfort preferences and optimization degree that according to these preferences, achievement of system is done. The energy consumption of 40% is obtained and in the inhabitants' behavior pattern, the algorithm was specialized. The 16.89% of reduction is obtained by the existing system and it was focused to obtain the agreement between the system and users for user preference satisfaction and the energy optimization is also performed at the same time.