Absorption Zone Research Articles

Synthesis, characterization and film preparation of 6FDA-based polyimides with polar groups arranged for thermal crosslinking

Abstract Thermal crosslinking of polyimides is a relevant methodology to increase their chemical resistance. This reaction is induced by heating after polymerization. Although this reaction is considered a viable route to modify polyimides, there is controversy over the specific temperature for the reaction. To contribute to the knowledge of crosslinked structures, we performed a differential scanning calorimetric (DSC) and solubility test studies on a series of polyimides with different molar ratios of carboxylic acid groups. With 3,5-diaminobenzoic acid (DABA) as a source of carboxylic acid groups, the copolyimides were synthesized from 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA) and 4,4ʹ-hexafluoropropylidenebis(p-phenylenoxy)dianiline (6FPA) to form blocks of 6FDA:6FPA (n) and 6FDA:DABA (m) from m = 0–100 %. Flat films were prepared at 50 ± 3 µm with polyimides. In the thermogram of the flat films, a heat absorption zone associated with the decarboxylation reaction was identified with an endothermic minimum at 260 °C, which was assigned to the crosslinking temperature. Furthermore, heating time was varied for 3–36 h to determine the insolubility of the thermally crosslinked polyimide; from 24 h of heating the polyimide were insoluble. The polyimides were thoroughly characterized by ATR-FTIR, 1H NMR, TGA, SEM, the fractional free volume (FFV) was determined by the Bondi’s group contribution method and solubility to different organic solvents. The FFV of crosslinked polyimides increases relative to pristine polyimides by 2 % for those with higher DABA content and 40 % for those with lower DABA content. Finally, also the glass transition temperature increases in the crosslinked polyimides relative to the pristine ones from 280 °C for the lowest DABA content to 402 °C for the highest DABA content, demonstrating the increase in the thermal resistance of the structure.

Mussel-inspired structure based CsPbBr3/Aramid nanofiber composite film for lightweight, flexible and superior X-ray shielding

Excessive exposure to X-rays risks human health and the proper functioning of precision instruments. Conventional materials have high atomic numbers, but their unsatisfactory mechanical properties hinder commercial application. Currently, X-ray shielding materials must fulfill the characteristics of high strength, lightweight, flexibility, high shielding efficiency, and low secondary radiation to alleviate urgent radiation risks. Here, this work introduces a mussel-inspired structure into the construction of the lightweight and flexible CsPbBr3/aramid nanofiber (ANF) composite films to enhance the ability of X-ray absorption. The CsPbBr3 provides effective X-ray shielding in millimeter thickness and addresses the challenge of absorption zone matching by containing both Cs and Pb elements. The interlayer reflection caused by the mussel-inspired structure increases the photon travel distance in the film, which synergizes with the absorption of X-rays by the elements, significantly improving shielding performance and weakening secondary radiation. The CsPbBr3/ANF composite film with 60 wt% CsPbBr3 content demonstrates robust tensile stress (57.6 MPa), lightweight (0.87 g/cm3), superior heat resistance, exceptional flexibility with a notable mass attenuation coefficient (58.2–65.6 cm2/g in the 20–70 kV range), which is much higher than Pb plate. Considering its comprehensive performance advantages, the CsPbBr3/ANF composite film significantly impacts the landscape of X-ray shielding.

Gastroretentive Drug Delivery Systems with improved Floating and Swelling Capabilities

For medications with an absorption window in the stomach and upper part of small intestine, a controlled drug delivery system with a longer stomach residence duration can be particularly useful. Rapid gastrointestinal transit may cause drug delivery system above the absorption zone to only partially release drug, which would reduce the supplied dose's effectiveness. The main drawbacks are linked to the non-uniformity of drug absorption across the alimentary canal and the inter- and intra-subject variability of gastro-intestinal transit time. The bioavailability of medications is predicted to be improved by floating delivery systems, which are designed to stay buoyant on the gastric contents for an extended period of time. Floating in combination with swellable system gaining attention due to their wide applicability in the targeting of drugs to stomach. These floating and swellable tablet have the advantage that they remain buoyant and swells to 2-3 folds in gastric fluid.

Mitigation of salt stress in lettuce by a biostimulant that protects the root absorption zone and improves biochemical responses.

Horticultural crops constantly face abiotic stress factors such as salinity, which have intensified in recent years due to accelerated climate change, significantly affecting their yields and profitability. Under these conditions, it has become necessary to implement effective and sustainable solutions to guarantee agricultural productivity and food security. The influence of BALOX®, a biostimulant of plant origin, was tested on the responses to salinity of Lactuca sativa L. var. longifolia plants exposed to salt concentrations up to 150 mM NaCl, evaluating different biometric and biochemical properties after 25 days of treatment. Control plants were cultivated under the same conditions but without the biostimulant treatment. An in situ analysis of root characteristics using a non-destructive, real-time method was also performed. The salt stress treatments inhibited plant growth, reduced chlorophyll and carotenoid contents, and increased the concentrations of Na+ and Cl- in roots and leaves while reducing those of Ca2+. BALOX® application had a positive effect because it stimulated plant growth and the level of Ca2+ and photosynthetic pigments. In addition, it reduced the content of Na+ and Cl- in the presence and the absence of salt. The biostimulant also reduced the salt-induced accumulation of stress biomarkers, such as proline, malondialdehyde (MDA), and hydrogen peroxide (H2O2). Therefore, BALOX® appears to significantly reduce osmotic, ionic and oxidative stress levels in salt-treated plants. Furthermore, the analysis of the salt treatments' and the biostimulant's direct effects on roots indicated that BALOX®'s primary mechanism of action probably involves improving plant nutrition, even under severe salt stress conditions, by protecting and stimulating the root absorption zone.

Fierce Feedback in an Obscured, Sub-Eddington State of the Seyfert 1.2 Markarian 817

Mrk 817 is a bright and variable Seyfert 1.2 active galactic nucleus (AGN). X-ray monitoring of Mrk 817 with the Neil Gehrels Swift Observatory in 2022 revealed that the source flux had declined to a lower level than recorded at any prior point in the then 19 yr mission. We present an analysis of deep XMM-Newton and NuSTAR observations obtained in this low flux state. The spectra reveal a complex X-ray wind consisting of neutral and ionized absorption zones. Three separate velocity components are detected as part of a structured ultrafast outflow (UFO), with v/c=0.043−0.003+0.007 , v/c=0.079−0.0008+0.003 , and v/c=0.074−0.005+0.004 . These projected velocities suggest that the wind likely arises at radii that are much smaller than the optical broad-line region. In order for each component of the outflow to contribute significant feedback, the volume filling factors must be greater than f ≃ 0.009, f ≃ 0.003, and f ≃ 0.3, respectively. For plausible, data-driven volume filling factors, these limits are passed, and the total outflow likely delivers the fierce feedback required to reshape its host environment, despite a modest radiative Eddington fraction of λ ≃ 0.008–0.016 (this range reflects plausible masses). UFOs are often detected at or above the Eddington limit; this result signals that black hole accretion has the potential to shape host galaxies even at modest Eddington fractions and over a larger fraction of a typical AGN lifetime. We discuss our findings in terms of models for disk winds and black hole feedback in this and other AGN.

Design and Development of Insulin Loaded Microspheres for Oral Delivery

Protease inhibitor-encapsulated human insulin microspheres were developed and evaluated in this research in order to determine the optimal formulation. Manufacturing human insulin microspheres involved coating them with eudragit S-100, stabilizing them with polyvinyl alcohol, and evaporating the solvent from w/o/w multiple emulsions. Excellent encapsulation efficiency and pH-dependent controlled release were demonstrated by human insulin-loaded eudragit L-100 microspheres with a protease inhibitor. This helped encapsulate and transfer insulin to the best absorption zone. Thus, insulin absorption and physiological response increased. Thus, insulin formulations enhance efficacy, making microsphere insulin injection more efficient as a diabetic treatment. Drug-polymer ratio affects microsphere size and form. The effect of emulsifying agent amount on microsphere size and manufacturing yield. Eudrajit RL, microspheres loaded with insulin, are more successfully formulated and manufactured at optimal concentrations of polymer and emulsifying agent

Flexible lightweight Bi2O3-rubber based materials for X-ray protection

The flexible X-ray protective materials are commonly made of lead rubber. They have heavy weight, high biological toxicity, poor flexibility and aging resistance. The "weak absorption zone" in the energy range of 40–88 keV threaten environmental safety and human health. Bi2O3-rubber based flexible X-ray protective materials were prepared by rubber production process. The micromorphology, shore hardness, specific gravity, mechanical properties and radiation protective properties were characterized and analyzed. The results showed that Bi2O3 particles dispersed in natural rubber (R) matrix uniformly. The shore hardness of samples fluctuated between 41° and 46° with the increasing Bi2O3 content, lower than the Level 1 index requirement of the hardness (≤80°) of lead-free composite protective materials. The specific gravity increased from 1.35 g/cm3 to 2.38 g/cm3, which reduced approximately 34% comparing with the commercial protective materials containing Pb. The breaking strength and breaking elongation meet the index requirements in National standard GB 16757-2016. When Bi2O3 content reached 300 parts, the highest lead equivalent and maximum shielding ratio were 0.3012 mmPb and 52.95% respectively. It meets the index requirement of lead equivalent of 0.25 mmPb≤Pb≤0.35 mmPb for the front sheet of protective clothing. The effective shielding range of the protective material R/Bi2O3(100/300) was mainly in the range of incident energy of 65∼100 keV and 164–250 keV, which covered the “weak absorption zone” of lead.

Effect of different aggregates on the properties of carbonated self-pulverized low-calcium clinker mortar

This study investigated the effects of four aggregates - standard sand, manufactured sand, slag, and coal gangue - on the properties of carbonated self-pulverized low-calcium clinker (SPLCC) mortars. The SPLCC, aggregates, and water were mixed in a mass ratio of 1.00:2.50:0.15 and compaction molded, then carbonation cured by 99.99 % CO2 exposure at 0.2 MPa. Tests determined the weight gain, compressive strength, water absorption, and interfacial transition zone (ITZ) microstructure after 1, 4, and 24 h of curing. Results showed the manufactured sand mortar had the highest compressive strength (39.7 MPa) and lowest water absorption (3.50 %) at 24 h, indicating the best macroscopic performance. This was due to the manufactured sand's stone powder content improving SPLCC binding and accelerating calcium carbonate accumulation in the ITZ. Nanoindentation revealed the manufactured sand mortar had the narrowest ITZ width (15 μm). SEM-BSE also showed higher Ca content in its ITZ. The Ca: Si ratio in the ITZ strongly correlated with strength and absorption. Overall, manufactured sand as aggregate can enhance carbonated SPLCC mortar properties, providing potential for precast products.

Susceptibility of Selected Crops to Simulated Imazethapyr Carryover: A Morpho-Anatomical Analysis

A bioassay study was conducted to determine the differences in the susceptibility of selected crops to simulated imazethapyr residues based on morphological and anatomical parameters. Sugar beet, white mustard, and rapeseed oil were found to be the most sensitive based on ED50 values for the root length and the root fresh weight. Corn and sunflower were less sensitive, and wheat was the least sensitive. The measured anatomical parameters confirmed the different sensitivities of the tested plants, as evidenced by a shortening of the meristem and elongation zones, a reduction in the distance between the root tip and the absorption zone, and the distance between the root tip and the point where the primordium of the lateral root appears. An imazethapyr residue level equivalent to ED20 (for root length) did not cause serious morphological changes in the less sensitive plants, nor did it cause significant changes in the length of the root cap, the beginning of the root absorption zone (root hair region), the beginning of lateral root formation (i.e., the permanent region), and the number of root primordia per root length. Therefore, ED20 could be proposed as an acceptable residue level (ARL) or herbicide residue level at which these plants can be safely sown.

Gamma radiation shielding simulation for thermoplastic elastomer and silicon rubber/alloy dopant with functional nanoparticle

With the global energy crisis worsening, the research and application of new energy have become a strategic objective for the major countries’ long-term development in the twenty-first century. Nuclear energy technology development and application have become central to new energy development. Numerous types of high-energy radiation (such as X-rays, gamma rays, and neutron rays) produced by nuclear materials not only impose stricter requirements on the radiation-resistant materials used in the reactor but also risk causing significant environmental pollution (nuclear pollution) and serious harm to human life and health if a leak does not form. As a result, the prudent control and protection of nuclear radiation have become critical issues in the development of nuclear energy. With the rapid development of nuclear power today, it is necessary to seek new nuclear radiation protection materials, particularly those with high energy, penetrating ability, and other neutron-protective material characteristics. This is a new type of nuclear power design and construction of critical materials. In this study, WinXCom software is used to simulate the shielding properties of the used functional shielding element, compounds of metal oxide, and the mixture of RTV and TPE with the functional nanoparticle and observe the K-edge absorption of the material used. Based on the simulation, the shielding performance of the selected element of Sm was observed to have the smallest weak gap absorption zone of 40-47 MeV in common medical radiation of 30-150 KeV. Different sets of combinations of shielding material were simulated and found that the combination of WO3 with Sm2O3 gave the most pronounced radiation shielding performance with two strong absorption peaks at 46.8 KeV and 69.5 KeV. RTV composite (Sm2O3+RTV+ WO3) with WO3 as matrix gave the best shielding performance and was used as a reference for the manufacture of the new type of shielding materials.

A Near-Infrared Enhanced Field-Line Crowding Based CMOS-Integrated Avalanche Photodiode

This paper presents a CMOS-integrated linear-mode avalanche photodiode based on electric field-line crowding (EFLC-APD) to form an effective multiplication zone and a wide absorption zone. The EFLC-APD possesses a hemispherical avalanching electric field at the n-well/p- epi junction formed due to the curvature of the half-sphere cathode. A lower electric field extends radially across the entire volume of the EFLC-APD towards the substrate and towards the surface anode. Because of such a distribution of the electric field, electrons photogenerated within the whole volume drift towards the cathode. Therefore, the EFLC-APD provides a large sensitive-area to total-area ratio while offering high responsivity and bandwidth for red and near-infrared light due to its thick absorption zone and drift-based carrier transport. It is shown that the electric field distribution can be modified by the design parameters such as cathode radius and diode size in addition to doping profiles. The EFLC-APD achieves a responsivity-bandwidth (R-BW) product of 49.5 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\frac{\mathrm{A}}{\mathrm{W}}\cdot$</tex-math></inline-formula> GHz, corresponding to the responsivity and bandwidth of 33 A/W and 1.5 GHz, respectively, at the wavelength of 850 nm. In addition, a maximum responsivity of 3.05 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\times\, 10^{\mathrm{3}}$</tex-math></inline-formula> A/W at 2 nW optical power is achieved for the red and near-infrared spectral range. Noise characterization resulted in an excess noise factor F = 6 measured at an avalanche gain of 56.7. Due to the high sensitive-area to total-area ratio, high responsivity, large bandwidth, and CMOS compatibility, this APD is a promising optical detector for many applications.

Cold plasma modes in the chiral Maxwell-Carroll-Field-Jackiw electrodynamics

In this work, we study the propagation and absorption of plasma waves in the chiral Maxwell-Carroll-Field-Jackiw (MCFJ) electrodynamics. The Maxwell equations are rewritten for a cold, uniform, and collisionless fluid plasma model, allowing us to determine the new refractive indices and propagating modes. The cases of propagation parallel and orthogonal to the magnetic field are examined considering a purely timelike CFJ background that plays the role of the magnetic conductivity chiral parameter. The collective electromagnetic modes are associated with four distinct refractive indices associated with right-circularly polarized and left-circularly polarized waves. For each index, the propagation and absorption zones are illustrated for some specific parameter values. In low-frequency regime, we have obtained modified helicons with right- and left-circularly polarizations. The optical behavior is investigated by means of the rotatory power (RP) and dichroism coefficient. The existence of a negative refraction zone enhances the rotatory power. It is also observed RP sign reversal, a feature of rotating plasmas.

Frequency spectrum of radiation transfer in high voltage circuit breaker arcs for polymer nozzle ablation in C4F7N and CO2 gas mixture

Arc radiation-induced polymer nozzle ablation plays a crucial role in the operation of self-blast circuit breakers. Up to now, there is no study specifically on the spectral distribution of radiated power from a switching arc towards the nozzle surface and its implication to nozzle ablation. Three-dimensional radiation transfer calculation has been performed in this study for arcs burning in the mixture of , a gaseous environment that is under significant focus in the development of SF6 free switching technology to aim net-zero by the middle of this century. Results show that photons from infrared to extreme ultraviolet (UV, up to 5 × 1015 Hz) are emitted from the core of high current arcs. However, the high-frequency photons are mostly absorbed within the arc column, especially at the arc edge, and only photons up to (far UV, 7 eV) can penetrate the arc edge and cold gas and reach the nozzle surface. The spectral distribution of the radiative energy at different instantaneous currents (15 kA, 28 kA and 60 kA peak) and different locations of the nozzle is presented and compared in detail. The location of the radiation absorption zone at the arc edge and the radiative power reaching the nozzle wall as a function of the instantaneous current is, in particular, purposely considered.

Weak Seismicity and Strongest Earthquakes Against the Background of the Variations of &lt;i&gt;S&lt;/i&gt;-wave Attenuation Field

The paper considers the role of relatively weak earthquakes as a tool for studying the environment, including of strong earthquake process. The spatial structure of the attenuation field of several seismically active regions (of the Garm prognostic polygon in Tajikistan, Altai, the Caucasus, Eastern Anatolia, the Western Tien Shan), as well as the epicentral regions of a number of strong earthquakes, and the confinement of deepened seismicity to it are considered. It is shown that the attenuation field obtained from the short-period code of weak earthquakes in seismically active regions is inhomogeneous and consists of blocks with a high Q factor and weakened zones of strong attenuation. An uneven distribution of deepened earthquakes is noted. It is associated with the block structure: in weakened zones, their share is greater than in blocks with a high Q factor. Examples of variations in the of deepened seismic activity in weakened zones are demonstrated. It varies over time, increasing before strong earthquakes. Facts are presented that testify to the existence of a relationship between the Earth’s rotation rate and the activity of deepened seismicity. Examples are given of the activation of weak seismicity in the form of seismic swarms (series of weak earthquakes concentrated in space and time) in connection with strong events. A characteristic feature of these swarm series is the isometry of the earthquake localization areas in plan view and vertical elongation. As a rule, they coincide with weakened zones of strong absorption of S-waves. Intense localized seismicity, confined to one-dimensional volumes, is most likely associated with increased conductivity channels through which deep fluids migrate. The activation of swarm series is the result of active migration of deep fluids and an increase in fluid saturation of weakened zones. Fluids, in turn, are a catalyst for processes that lead to a decrease in the strength of rocks and the destruction of blocks in epicentral zones. In this case, the clusters to which the swarm series belong can be considered as local seismogenic zones. The appearance of compact isometric in plan and nearly vertical in section clusters of weak seismicity is often observed outside the epicentral zones of strong earthquakes. Such zones may simply be indicators of the seismotectonic situation in the region as a whole. It is assumed that a sharp change in the dynamics of atmospheric pressure during the preparation of a strong earthquake at hydrometeorological stations located in such areas is a consequence of the intergeospheric interaction of the lithosphere and atmosphere. Deep degassing seems to be one of the main mechanisms of the anomalous behavior of atmospheric pressure during the implementation of strong events. It is most active in weakened zones. The mechanisms of the impact of deep degassing on the outer geospheres remain the subject of discussion.

Study of lead free double perovskites Na2XAgCl6 (X = Ga, In Tl) for solar cells and transport applications

The double perovskites are rich merchant to harvest energy from solar cells and thermoelectric generators to cover up its shortfall. Therefore, in this article, the electronic, optical, and thermoelectric characteristics of Na2XAgCl6 (X = Ga, In Tl) are briefly elaborated. The tolerance and octahedral factors are calculated for structural stability and formations energy for thermodynamically existence. The band structures are show the tuning of band gap from 2.57 eV to 1.30 eV by the changing cations from Ga to Tl. The density of states shows the p-d hybridization among X, Ag and Cl ions is responsible for decreasing band gap. The optical analysis in terms of dielectric constant, absorption and other dependent parameters illustrate broad absorption bands in ultraviolet region (Ga, In) and in visible region (Tl). The shifting of absorption zone to visible region increase their potential for solar cells. Thermoelectric calculations have been performed to evaluate the electrical conductivity, Seebeck coefficient, and thermal conductivity by BoltzTraP code. The large figure of merit and extremely small lattice thermal conductivity at room temperature also make them important for thermoelectric generators fabrication to harvest heat energy.

Estimating the Effects of Deficit Irrigation on Water Absorption and Utilization of Tomatoes Grown in Greenhouse with Hydrus-1D Model

Quantitative analysis of tomato root water uptake and soil water utilization in the root zone under deficit irrigation is an important tool to improve agricultural water utilization efficiency. In this study, three different deficit irrigation levels were set at the flowering and fruit development stage (Stage I) and the fruit-ripening stage (Stage II), respectively. The Hydrus-1D model and field data were used to analyze the effects of deficit irrigation on tomato root growth, soil water uptake and utilization in the root zone. The results showed that deficit irrigation could reduce the total root length density of water-absorbed roots but increase the water-absorbed root length density of the underlying soil (30–60 cm). Moderate and severe water deficits at Stage II increased the water-absorbed root length density of the underlying soil by 0.10–6.26% and 2.12–11.71% compared with a mild water deficit. Considering tomato root growth, the Hydrus-1D model can improve the accuracy of soil moisture simulation. The main water absorption zone of tomato roots was 0–30 cm. Compared with full irrigation, the ratio of water absorption by the underlying root system (30–60 cm) to the total water absorption of the profile (0–60 cm) increased by 2.16–2.82% and 5.34–6.34% due to mild and moderate water deficits at Stage I. At Stage I and Stage II, a water deficit could reduce soil evaporation. T3 had the highest water use efficiency in two years, which was 24.07% (T9) and 20.47% (T8) higher than the lowest value, respectively. The optimal deficit irrigation scheme under this experiment condition is as follows: the soil water content was 70–90% θf (field capacity) at Stage I and was 40–60% θf at Stage II (T3).

Sharp-edged pencil type ZnO flowers and BiOI flakes combined with carbon nanofibers as heterostructured hybrid photocatalysts for the removal of hazardous pollutants from contaminated water

The growth of advanced micro-and nanostructures with metal oxides has consistently generated extraordinary interest in energy and environmental applications. Cutting-edge nanostructures exhibit superior reactive sites and surface areas, thus improving the performance in crucial domains. In this study, sharp-edged pencil-type ZnO flowers and BiOI flakes as pristine materials, and their composition with carbon nanofibers (CNFs) (ZnO–BiOI@CNFs) as a hetero hybrid catalyst as well as binary compositions such as ZnO–BiOI, ZnO@CNFs, and BiOI@CNFs catalysts were fabricated using a simple and convenient hydrothermal synthesis process. The composition of newly produced innovative nanostructures was examined for azo dye degradation under solar simulator exposure. Dye degradation of ∼95% was achieved by the hybrid catalyst (ZnO–BiOI@CNFs) during 120 min of irradiation, which was ∼1.8 and 2.1-times higher than pristine ZnO and BiOI nanostructures, respectively.The improved hybrid catalysts were able to degrade methyl orange (MO) and rhodamine B (RhB) dyes. Importantly, mixed dyes RhB, MO, and azo dye demonstrated 47% dye degradation using a hybrid catalyst. These mixed dye-scalable hybrid catalyst performances offer additional insights into commercialization/industrialization. The outstanding performance of the hybrid catalyst is attributed to the unidirectional electron flow with pencil-like ZnO, a catalyst with a larger absorption zone, high surface area, and reactive sites, particularly ZnO and BiOI nanostructures, and decreased recombination rate with a heterojunction interface. In addition, CNFs can operate as electron traps and sinks, providing very quick redox reactions. To produce the sophisticated nanostructures with homogeneous morphologies, this work presents new insights into energy and environmental applications.

Synthesis, crystal structure, and photo-luminescence properties of a cyan-emitting β-Mg2.25Al3·5Si5·25O18:Eu2+

At the synthesis temperature of α-cordierite (α-Mg2Al4Si5O18), compositions of Mg2+xAl4-2xSi5+xO18 crystallized as β-cordierite (β-Mg2+xAl4-2xSi5+xO18) when x is over 0.2. By doping Eu2+ into optimal host β-Mg2.25Al3·5Si5·25O18 (β-MASO), a series of novel cyan luminescence materials were obtained. Excitation spectra ranged from 250 to 450 nm, and peaked around 365 nm. Under wavelength of excitation peaks, emission maximum of series samples moves from 464 nm to 485 nm with the increase of Eu2+. Decay behaviors and Gaussian multiple fitting results of emission spectrum, consistent with crystal analysis that the Eu2+ occupy three kinds of crystallographic sites. For representative sample β-MASO:0.02Eu2+, internal quantum efficiencies (η1) is about ∼56.96%, and its emission intensity remains at 66% of initial intensity at 150 °C. Under excitation at UV (365 nm) lamp, the white light with warm tune was obtained by mixing β-MASO:0.02Eu2+ with red CaAlSiN3:Eu2+. The electro-luminescence spectrum mainly distributes in blue (400–520 nm) and red (600–740 nm) regions and overlap with main absorption zone of plants.

Assessment of rainwater absorption zone in Citarum Watershed using GIS and AHP

Watershed performance can be seen from various aspects, including the ability of the land to absorb water, the amount of erosion, water quality, and water regime index. This study is an effort to manage critical watersheds in managing water absorption based on biophysical parameters such as soil type, slope, geology, rainfall, and land cover. This research was conducted in 2021 in the Citarum watershed, limited to shallow aquifers. It is important to be mapped because it is part of 15 critical watersheds in Indonesia. The method used is to integrate RS, GIS, and Analytical Hierarchy Process (AHP). The results showed that there was a distribution of water absorption in the Citarum watershed, including very low 1.04%, low 21.33%, Medium 25.20%, high 38.80%, and very high 13.63%, with a total area of 638,511.57 ha. The dominant absorption rate is relatively high, 38.8%, and very high, 13.63%, influencing water availability in the Citarum watershed. From this study, AHP shows that the most influential in water infiltration into shallow aquifers is soil, with a score of 0.5, followed by Rainfall Criteria with a score of 0.26, followed by the land cover at 0.13, then slope and geology.

Geophysical imaging of tree root absorption and conduction zones under field conditions: a comparison of common geoelectrical methods

Geophysical imaging of tree root absorption and conduction zones under field conditions: a comparison of common geoelectrical methods