Search Results (51)

Sustainable planning in New Sohag City, Egypt, can be significantly enhanced by employing integrated geophysical techniques. The current research presents the applicability of multiple integrated geophysical methods to prepare the optimal land use plans for the sustainable development of the new urban extension of Sohag Governorate, Upper Egypt, to tackle residential density and overcrowding in the governorate. The utilized geophysical techniques were electrical resistivity tomography (ERT), seismic refraction (SR), and ground penetrating radar (GPR). All these applied geophysical techniques concluded the near-surface stratigraphic sequence, which can be summarized by a generic subsurface model: variable wadi-fill deposits due to the variation in the flooding nature of the Nile River over the past millions of years, with an average thickness of 4.1 m; wet sand with intercalations of silt and clay, with an average thickness of 9.2 m. The model ends with highly saturated sand and gravel deposits, representing the groundwater aquifer throughout the studied area. The integration of the geophysical techniques, as well as the geological investigation, proved a clear efficacy for preparing the optimal land-use plan of the studied site, in the form of the proposed extensions of the agricultural activities, green and open areas, old quarrying areas, construction areas, and the groundwater potential throughout the studied area to conserve natural resources and ensure sustainable land use. Full article

Surface optical losses represent one of the critical factors limiting the photogenerated current density and power conversion efficiency (PCE) of perovskite solar cells (PSCs). To address this issue, this paper introduces a pyramid/porous composite structure on the light-facing surface of PSCs. The pyramids and porous structures are obtained on silicon surfaces via alkaline wet etching and metal-assisted chemical etching, respectively, and then replicated onto the cell surface using nanoimprint technology. The research findings indicate that the micrometer-scale pyramids induce multiple refractions of incident light, enhancing the probability of photons entering the interior of the cell. Moreover, the nanoscale porous structures on the pyramid mitigate the refractive index difference between air and the pyramid material, thereby reducing reflection losses for single-incident light. For the optimized pyramid/porous structure, a reduction in surface reflectivity from 40.3% to 5.1% is observed on silicon. Benefiting from the suppression of surface reflection losses by the pyramid/porous structure, the response spectrum of the PSCs is significantly improved. Consequently, the photogenerated current density of the device increases from 21.62 to 23.86 mA cm⁻², with a relative enhancement in PCE by 9.5%. Full article

SiN_x:H film deposition via plasma-enhanced chemical vapor deposition has been widely used in semiconductor devices. However, the relationship between the chemical bonds and the physical and chemical properties has rarely been studied for films deposited using tools in terms of the actual volume production. In this study, we investigated the effects of the deposition conditions on the H-related chemical bonding, physical and chemical properties, yield, and quality of SiN_x:H films used as passivation layers at the 28 nm technology node. The radiofrequency (RF) power, electrode plate spacing, temperature, chamber pressure, and SiH₄:NH₃ gas flow ratio were selected as the deposition parameters. The results show a clear relationship between the H-related chemical bonds and the examined film properties. The difference in the refractive index (RI) and breakdown field (E_B) of the SiN_x:H films is mainly attributed to the change in the Si–H:N–H ratio. As the Si–H:N–H ratio increased, the RI and E_B showed linear growth and exponential downward trends, respectively. In addition, compared with the Si–H:N–H ratio, the total Si–H and N–H contents had a greater impact on the wet etching rates of the SiN_x:H films, but the stress was not entirely dependent on the total Si–H and N–H contents. Notably, excessive electrode plate spacing can lead to a significant undesired increase in the non-uniformity and surface roughness of SiN_x:H films. This study provides industry-level processing guidance for the development of advanced silicon nitride film deposition technology. Full article

Wet milling is a fractionation process widely used in the corn industry, which allows the separation of its main chemical components (starch, proteins, fiber and lipids) with high efficiency and purity compared to dry milling. The first stage of this process consists of maceration; after softening the grain, the actual milling is carried out, and the germ is separated by flotation because of its high lipid content. The chemical composition of pseudocereals is similar to that of cereals, hence their name, so they could be processed in the same way. In this way, the traditional corn wet milling process was adapted to quinoa. The objective of this work is to isolate the germ of red Bolivian Royal quinoa using wet milling, and evaluate its efficiency and physicochemical characteristics due to its large size and nutrient concentration. By cold pressing the red quinoa germ, crude oil was obtained and characterized in terms of: Acid Index, Iodine Index, Saponification Index, K Index, Refractive Index (20 °C) and fatty acid composition, determined by gas chromatography coupled to a mass detector (GC-MS). This profile was compared with the fatty acid profile of the solvent-extracted quinoa oil, and it was observed that there were no significant differences between the two oil samples. In addition, the sample obtained via cold pressing showed similar characteristics to corn oil, except for a higher Saponification Index and proportion of linolenic acid (omega-3). Full article

Sample homogeneity dictates whether analyzing a test portion of an entire sample can provide representative information about incurred mycotoxins. In this study, we evaluated particle-size-distribution-based homogeneity of laboratory mycotoxin samples using laser diffraction particle size analysis and International Organization for Standardization (ISO) Guide 35: 2017. Incurred whole corn, compound feed, peanut butter, and wheat flour (500 g each) were comminuted using wet, cryogenic, or dry milling. We used a sample dividing (riffling) device to obtain representative subsamples (25 g each) and developed a laser diffraction particle size analysis procedure by optimizing key parameters such as the refractive index, absorption, and stirring rate. The homogeneity of the particle size distribution within laboratory subsamples was characterized using the optimized laser diffraction procedure. An assessment of homogeneity was also performed for individual mycotoxins in each incurred matrix sample following the procedure described in ISO Guide 35. The concentrations of the incurred mycotoxins were determined using liquid chromatography–mass spectrometry (LC-MS). Within- and between-subsample variances of incurred aflatoxin B1 in peanut butter; deoxynivalenol in corn, compound feed, and wheat flour; and fumonisins in compound feed corroborated that when the particle size measurements were less than 850 µm, mycotoxins concentrations were consistent across independent test portions, which was confirmed using an analysis of variance (F-test). This study highlights the benefits of laser diffraction particle size analysis and suggests its use as a test procedure to evaluate homogeneity in new sample commodities. Full article

A distributed optical fiber refractive index sensor based on etched Ge-doped SMF in optical frequency domain reflection (OFDR) was proposed and demonstrated. The etched Ge-doped SMF was obtained by only using wet-etching, i.e., hydrofluoric acid solution. The distributed refractive index sensing is achieved by measuring the spectral shift of the local RBS spectra using OFDR. The sensing length of 10 cm and the spatial resolution of 5.25 mm are achieved in the experiment. The refractive index sensing range is as wide as 1.33–1.44 refractive index units (RIU), where the average sensitivity was about 757 GHz/RIU. Moreover, the maximum sensitivity of 2396.9 GHZ/RIU is obtained between 1.43 and 1.44 RIU. Full article

To meet the requirements of trellis grape crop root irrigation, spraying pesticides on branches and leaves, an integrated sprinkler was designed, which relies on the flow pressure to change the irrigation water and spray pesticide working modes. The structural parameters that affect the hydraulic performance were selected based on the working principle of the sprinkler. The key parameters for the irrigation mode included diversion hole inclination angle, refractive cone angle, refractive cone length, and cone hole distance. The key parameters for the spray pesticide mode included diversion chute width, the number of diversion chutes, the diversion chute inclination angle, the rotary acceleration chamber height, and the nozzle outlet cylindrical section length. The central composite design response surface tests of the water–pesticide integrated sprinkler were carried out; the analysis of variance and regression analysis were selected; the main influence rules and interactions of key structural parameters on irrigation performance and pesticide spraying performance of sprinkler irrigation system were obtained. The optimal parameters of the water–pesticide integrated sprinkler were: the diversion hole inclination angle is 20.8°, the refractive cone angle is 123.7°, the refractive cone length is 8.8 mm, the cone hole distance is 3.6 mm, the diversion chute width is 2.5 mm, the number of diversion chutes is 2, the diversion chute inclination angle is 10°, the rotary acceleration chamber height is 1.3 mm, and the nozzle outlet cylindrical section length is 0.7 mm. The irrigation hydraulic performance of the wetted radius is 3.4 m, the average irrigation application rate is 0.65 mm/h, and the uniformity coefficient is 88%. The spraying pesticide performance of the droplet volume mid-diameter is 200.2 μm, the droplet spectrum width is 2.2, and the droplet coverage is 9.4%. Full article

A series of poly(vinyl acetate-co-2-hydroxyethylmethacrylate)/acyclovir drug carrier systems (HEMAVAC) containing different acyclovir contents was prepared through bulk free radical polymerization of 2-hydroxyethyl methacrylate with vinyl acetate (VAc) in presence of acyclovir (ACVR) as the drug using a LED lamp in presence of camphorquinone as the photoinitiator. The structure of the drug carrier system was confirmed by FTIR and ¹HNMR analysis, and the uniform dispersion of the drug particles in the carrier was proved by DSC and XRD analysis. The study of the physico-chemical properties of the prepared materials, such as the transparency, swelling capacity, wettability and optical refraction, was carried out by UV–visible analysis, a swelling test and measurement of the contact angle and the refractive index, respectively. The elastic modulus and the yield strength of the wet prepared materials were examined by dynamic mechanical analysis. The cytotoxicity of the prepared materials and cell adhesion on these systems were studied by LDH assay and the MTT test, respectively. The results obtained were comparable to those of standard lenses with a transparency of 76.90–89.51%, a swelling capacity of 42.23–81.80% by weight, a wettability of 75.95–89.04°, a refractive index of 1.4301–1.4526 and a modulus of elasticity of 0.67–1.50 MPa, depending on the ACVR content. It was also shown that these materials exhibit no significant cytotoxicity; on the other hand, they show significant cell adhesion. The in vitro dynamic release of ACVR in water revealed that the HEMAVAC drug carrier can consistently deliver uniformly adequate amounts of ACVR (5.04–36 wt%) over a long period (7 days) in two steps. It was also found that the solubility of ACVR obtained from the release process was improved by 1.4 times that obtained by direct solubility of the drug in powder form at the same temperature. Full article

Constructing accurate models that provide information about water vapor content in the troposphere improves the reliability of numerical weather forecasts and the position accuracy of low-cost Global Navigation Satellite System (GNSS) receivers. However, developing models with high spatial-temporal resolution demands compact observational datasets in the regions of interest. Empirical models, such as the Global Pressure and Temperature 3 (GPT3w), have been constructed based on the monthly averaged outputs of numerical weather models. These models are based on the assimilation of existing measurements to provide estimations of atmospheric parameters. Therefore, their accuracy may be reduced over regions with a low resolution of radiosonde or continuous GNSS stations. By emerging and increasing the Low-Earth-Orbiting (LEO) satellites that measure atmospheric parameter profiles using the Radio Occultation (RO) technique, new opportunities have appeared to acquire high-resolution atmospheric observations at different altitudes. This study aims to apply these RO observations to improve the accuracy of the GPT3w model over Iran, which is sparse in terms of long-term GNSS and radiosonde measurements. The temperature, pressure, and water vapor pressure parameters from the GPT3w model have been used as the input layers of the Extremely Learning Machine (ELM) technique. The wet refractivity indices from the RO technique are considered target parameters in the output layer to train the ELM. The RO observations of 2007–2020 are applied for training, and those of 2020–2022 for evaluating the performance of the developed ELM. Our numerical results indicate that the developed ELM decreases the Root-Mean-Square Error (RMSE) values of the wet refractivity indices by about 17 percent, compared to the original GPT3w RMSE values. Additionally, the wet refractivity indices from ELM have revealed correlation coefficients of about 0.64, which is about 1.9 times those related to the original GPT3w model. The performance of ELM has also been examined by comparison with the data of six located radiosonde stations covering the year 2020. This comparison shows an improvement of about 14 percent in the average RMSE values of the estimated wet refractivity indices. Full article

According to GPS radio occultation data from previous studies, the height of the planetary boundary layer (PBLH) is defined as the altitude at which the vertical gradient of refractivity N is at its local minimum, called the gradient approach. As with its density, the atmosphere’s refractivity falls broadly exponentially with height. The spherically symmetric refractivity N_ss(r) was established to account for the standard deviation of atmospheric refractivity with altitude. N_i is the residual from the fundamental vertical variations of refractivity, defined as N_i(r) = N(r) − N_ss(r). In this study, the vertical gradient of N is replaced by the vertical gradient of N_i to optimize the gradient approach, called the local gradient approach. Using the US radiosonde and Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) radio occultations (ROs) data from 2007–2011, these two PBLH-determining approaches are evaluated. The PBLHs estimated by the gradient approach and the local gradient approach have RMSE values of 0.73 km and 0.65 km, respectively. The PBLH obtained by the local gradient approach is closer to the radiosonde-derived value. In this paper, the COSMIC-2 ROs data and the western Pacific typhoon best track data are collocated in time and space during 2020–2021, and the axisymmetric composite structural characteristics of the tropical cyclone (TC) PBLs are analyzed. The lowest vertical gradients of N and N_i of TCs correspond closely with the average PBLHs. We find that the mean PBLHs of tropical depressions (TD), tropical storms (TS), and typhoons (TY) all have their local maxima at a radial distance of 125 km with heights of 1.03 km, 1.12 km, and 1.36 km, respectively. After 375 km, 575 km, and 935 km of TD, TS, and TY radial distances, the mean PBLHs become stable and cease to vary. The mean PBLH undulations increase significantly with the increase in tropical cyclone intensity. N_iwet is the residual from the fundamental vertical variations of wet refractivity, defined as N_iwet(r) = N_wet(r) − N_sswet(r). Local minima of N_iwet and N_i vertical gradients of TD, TS, and TY have comparable distributions and are concentrated between 0.5 km and 1 km. Full article

Port fuel injection is an important technical route in methanol engines. To obtain a theoretical basis for injector arrangement and injection strategy development in methanol engines, an optimal experimental platform based on diffuse back-illumination and the refractive index matching method (RIM) was designed and built in this study. The experiments on the behavior of low-pressure methanol spray-wall impingement and wall film were carried out and the influence of the three boundary conditions of spray distance (D_imp), wall temperature (T_wall), and injection pressure (P_inj) were analyzed comprehensively. Results showed that with the increase of D_imp, the overall shape of spray before impinging the wall changed from conical to cylindrical. The impinging spray height H_i and impinging spray width W_i increased with the decrease of D_imp and the increase of P_inj. Adhesive fuel film mass M_f increased with the increase of D_imp due to the decrease of kinetic energy during wall impact. In addition, the increase of the wall temperature T_wall reduced M_f due to evaporation, but when T_wall reached 423 K, M_f rebounded due to the Leidenfrost effect. The results of this study are helpful to improve the accuracy of the numerical methanol engine model. Full article

Time-series interferometric synthetic aperture radar (TS-InSAR) is often affected by tropospheric artifacts caused by temporal and spatial variability in the atmospheric refractive index. Conventional temporal and spatial filtering cannot effectively distinguish topography-related stratified delays, leading to biased estimates of the deformation phases. Here, we propose a TS-InSAR atmospheric delay correction method based on ERA-5; the robustness and accuracy of ERA-5 data under the influence of different atmospheric delays were explored. Notably, (1) wet delay was the main factor affecting tropospheric delay within the interferogram; the higher spatial and temporal resolution of ERA-5 can capture the wet delay signal better than MERRA-2. (2) The proposed method can mitigate the atmospheric delay component in the interferogram; the average standard deviation (STD) reduction for the Radarsat-2 and Sentinel-1A interferograms were 19.68 and 14.75%, respectively. (3) Compared to the empirical linear model, the correlation between the stratified delays estimated by the two methods reached 0.73. We applied this method for the first time to a ground subsidence study in the Yuxi Basin and successfully detected three subsidence centers. We analyzed and discussed ground deformation causes based on rainfall and fault zones. Finally, we verified the accuracy of the proposed method by using leveling monitoring data. Full article

The global navigation satellite system (GNSS) radio occultation (RO) is becoming an essential component of National Oceanic and Atmospheric Administration (NOAA) observation systems. The constellation observing system for meteorology, ionosphere, and climate (COSMIC) 2 mission and the Formosa satellite mission 7, a COSMIC follow-on mission, is now the NOAA’s backbone RO mission. The NOAA’s dedicated GNSS RO SAtellite processing and science Application Center (RO-SAAC) was established at the Center for Satellite Applications and Research (STAR). To better quantify how the observation uncertainty from clock error and geometry determination may propagate to bending angle and refractivity profiles, STAR has developed the GNSS RO data processing and validation system. This study describes the COSMIC-2 neutral atmospheric temperature and moisture profile inversion algorithms at STAR. We used RS41 and ERA5, and UCAR 1D-Var products (wetPrf2) to validate the accuracy and uncertainty of the STAR 1D-Var thermal profiles. The STAR-RS41 temperature differences are less than a few tenths of 1 K from 8 km to 30 km altitude with a standard deviation (std) of 1.5–2 K. The mean STAR-RS41 water vapor specific humidity difference and the standard deviation are −0.35 g/kg and 1.2 g/kg, respectively. We also used the 1D-Var-derived temperature and water vapor profiles to compute the simulated brightness temperature (BTs) for advanced technology microwave sounder (ATMS) and cross-track infrared sounder (CrIS) channels and compared them to the collocated ATMS and CrIS measurements. The BT differences of STAR COSMIC-2-simulated BTs relative to SNPP ATMS are less than 0.1 K over all ATMS channels. Full article

The use of pergola trellis crops has led to a need for irrigation and the spraying of pesticides. Thus, a new integrated micro-nozzle was designed to provide water and pesticides. The structural parameters that affect the irrigation performance were selected based on the working principle of the sprinkler. They included the outlet diameter, refractive surface angle, and the distance from the outlet plane to the refractive surface (cone hole distance). The structural parameters that affect the performance of spraying pesticide included the number of diversion chutes, nozzle diameter, and nozzle outer cone angle. The structural optimization of the water–pesticide integrated sprinkler was determined by a single-factor and a three-factors four-levels orthogonal tests. The indices used to evaluate the performance of the sprinkler were irrigation flow rate, wetted radius, and uniformity coefficient. Those used to evaluate the performance at spraying pesticides included the flow rate of spraying pesticides, spray cone angle, and relative size range of the droplets. The entropy weight and the extreme difference analytical methods were used to process the test data. The main order of the influence of key structural parameters on the irrigation performance was obtained as follows: outlet diameter, refractive surface angle, and cone hole distance. The primary and secondary order of the influence on the performance of spraying pesticide was as follows: the number of diversion chutes, angle of the outer cone of the nozzle, and nozzle diameter. The optimal combination of parameters for this water–pesticide integrated micro sprinkler was obtained as follows: outlet diameter 2.0 mm, refractive surface angle 30°, cone hole distance 1.0 d, nozzle diameter 3.0 mm, two diversion chutes, and nozzle outer cone angle 90°. The performance indices included the irrigation water flow rate 0.284 m³/h, wetted radius 4.26 m, uniformity coefficient 91.07%, flow rate of pesticides spread 0.097 m³/h, spray cone angle 121.25°, and average relative distribution span of droplets 1.18. The results provide an important theoretical basis for the practical application of sprinklers. Full article

The temperature distribution of shallow sectors of coastal aquifers are highly influenced by the atmospheric temperature and recharge. However, geothermal heat or vertical fluxes due to the presence of the saline wedge have more influence at deeper locations. In this study, using numerical models that account for variable density, periodic oscillations of temperature have been detected, and their origin has been attributed to the influence exerted by recharge and tides. The combined analysis of field data and numerical models showed that the alternation of dry and wet periods modifies heat distribution in deep zones (>100 m) of the aquifer. Oscillations with diurnal and semidiurnal frequencies have been detected for groundwater temperature, but they show differences in terms of amplitudes and delay with electrical conductivity (EC). The main driver of the temperature oscillations is the forward and backward displacement of the freshwater–saltwater interface, and the associated thermal plume generated by the upward flow from the aquifer basement. These oscillations are amplified at the interfaces between layers with different hydraulic conductivity, where thermal contours are affected by refraction. Full article