Reduction In Aperture Research Articles

A Plasma Membrane Intrinsic Protein Gene OfPIP2 Involved in Promoting Petal Expansion and Drought Resistance in Osmanthus fragrans

Osmanthus fragrans, a native to China, is renowned as a highly popular gardening plant. However, this plant faces significant challenges from drought stress, which can adversely affect its flowering. In this study, we found that the plasma membrane-localized gene OfPIP2 exhibited a substantial upregulation during the flowering stages and in response to drought stress. GUS staining has illustrated that the OfPIP2 promoter can drive GUS activity under drought conditions. The overexpression of OfPIP2 was found to enhance petal size by modulating epidermal cell dimensions in Petunia and tobacco. Moreover, this overexpression also bolstered drought tolerance, as evidenced by a reduction in stomatal aperture in both species. Furthermore, yeast one-hybrid (Y1H) and dual-luciferase (Dual-LUC) assays have indicated that the transcription factor OfMYB28 directly binds to the OfPIP2 promoter, thereby regulating its expression. Together, we speculated that a module of OfMYB28-OfPIP2 was not only involved in the enhancement of petal size but also conferred the improvement of drought tolerance in O. fragrans. These results contribute valuable insights into the molecular function of the OfPIP2 gene and lay a foundation for molecular breeding strategies in O. fragrans.

A new diamond-shaped periodic permanent magnet electromagnetic acoustic transducer for side-lobe suppression of shear horizontal ultrasonic waves

Periodic permanent magnet electromagnetic acoustic transducers (PPM EMATs) effectively generate shear horizontal (SH) ultrasonic guided waves in metallic media. Depending on their construction parameters, PPM EMATs can generate ultrasonic waves towards unwanted directions, due to the presence of side lobes in their radiation pattern. In this paper, a new PPM-like EMAT is proposed with the objective of reducing the side-lobe level in the radiation pattern of PPM EMATs. This was achieved by altering the magnets’ dimension in the PPM array following a diamond-like shape, reducing their width as one gets further from the centre of the transducer. The radiation behaviour of the EMAT was evaluated by means of an apodization factor, defined as the aperture reduction ratio. The side-lobe level showed a maximum reduction for an apodization factor of approximately 2. Four different configurations of the new PPM-like EMAT design and two reference conventional PPM EMATs were fabricated and experimentally evaluated on an aluminium plate. Experimental radiation patterns were compared to analytical model results showing good agreement. Relative to the conventional PPM EMAT, the new apodized diamond-shaped PPM EMAT presented a side lobe suppression of up to approximately 8 dB.

Functional characterization of ZjPYL8 from sour jujube: enhancing the sensitivity of stomata and roots to ABA in Arabidopsis thaliana

Abscisic acid (ABA) is a plant hormone that plays a crucial role in regulating plant growth, development, and adaptation to stress. The growth of Ziziphus jujuba Mill. var. spinosa (Bunge) Hu ex H. Chou, commonly known as Suanzao in Chinese, is significantly influenced by environmental factors, particularly drought and salt stresses. In this study, we isolated and characterized a putative ABA receptor, ZjPYL8, from Sour jujube. To investigate the effects of ZjPYL8 overexpression on ABA-responsive pathways, we introduced it into Arabidopsis thaliana (A. thaliana) and examined the resulting phenotypes. Our results demonstrated that overexpression of ZjPYL8 in A. thaliana led to a significant reduction in stomatal aperture and root length under ABA treatment, while the wild type (WT) was relatively insensitive to ABA. Moreover, ZjPYL8 transgenic plants exhibited shorter roots under salt treatment than the WT did. These findings suggest that the overexpression of ZjPYL8 in A. thaliana enhances the plant's resistance to stress and support the hypothesis that ZjPYL8 serves as a putative ABA receptor in Sour jujube, which may improve the plant's adaptability to drought and salt stresses. ZjPYL8 appears to mediate plant responses to ABA, similar to most ABA receptors in A. thaliana, such as stomatal closure and root length.

Influence of injection methods on bio-mediated precipitation of carbonates in fracture-mimicking microfluidic chip

Enzymatically induced carbonate precipitation (EICP) is a potential method to alter the hydraulic properties of fractured rocks. The pore-scale in-situ formation of bio-mediated precipitated carbonates in fracture-mimicking channels was investigated experimentally through a visualization platform and microfluidic technology. Image processing was employed to analyze the precipitation behavior. Three representative biogrouting methods (one-phase continuous injection, one-phase staged injection, and two-phase staged injection) and the role of nucleation agents were examined in this study. Results revealed that more amorphous substances formed during one-phase injection process, and the one-phase staged injection method exhibited superior precipitation efficiency, while two-phase staged injection method demonstrated better effectiveness in channel clogging. The addition of nucleation agents resulted in the channel-like precipitation pattern, compared to formation of more crystals in the absence of additives. The hydrodynamic coupling between precipitation and flow velocity was used to explain the mechanisms of fracture sealing. Precipitation and aggregation led to the reduction in microchannel aperture, thereby influencing the flow field. Under flow-induced shearing, the amorphous substances could be transported and settled on the channel surface, leading to a self-enhancing process in channeling. This study provides insights into the microscopic mechanisms of EICP and advances the application of EICP in fracture repairing.

Numerical modeling on nuclide transport around a nuclear waste repository under coupled thermo-hydro-mechanical condition

Coupled thermo-hydro-mechanical (THM) processes may raise the uncertainty of nuclide transport behavior in long-term operation of nuclear waste repository. A far-field modeling framework on nuclide transport around a nuclear waste repository under coupled THM conditions was developed and verified. Base on conceptual models of high-level waste repository in fractured rocks, a three-dimensional repository model including a vertical fault and a horizontal fracture was built, and influence of coupled THM processes on nuclide transport is numerically investigated. Effects of repository depth, fracture inclination, and internal aperture heterogeneity were investigated using the developed model. The results show that the coupled THM processes significantly affect nuclide transport behavior, especially in the early stages of nuclide leaching. The thermal stress induced by heat release of nuclear waste causes the reduction in fracture aperture around the repository. The nuclide transport under THM conditions is retarded before 103 years than that under hydraulic condition. The deeper locations of the candidate repository exhibit the lower rate of nuclide transport. The inclined fracture induces opposite flow directions between two fractures, which causes the delaying of nuclide transport. Fractures with heterogeneous apertures have preferential flow paths, which results in early arrivals of nuclide transport than fractures with homogenous apertures.

Aperture Reduction Using Downward and Upward Bending Arms for Dual-Polarized Quadruple-Folded-Dipole Antennas

A method to miniaturize the aperture of a dual-polarized quadruple-folded-dipole (QFD) antenna by bending its arms downward or upward is proposed in this letter. Two practical prototypes called downward-bending-arm (DBA) antenna and upward-bending-arm (UBA) antenna are presented and elaborated. Both the DBA and UBA antennas have four pairs of arms bent downward or upward along the four edges of the planar QFDs, respectively, which enable the aperture of the DBA and UBA antennas to shrink to around <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$0.24{\lambda }_0 \times 0.24{\lambda }_0$</tex-math></inline-formula> ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">${{\rm{\lambda }}}_{0}$</tex-math></inline-formula> is the free-space wavelength at 2 GHz). Both antennas can achieve relatively small apertures while ensuring good matching, isolation, and radiation performances within the band of interest. Especially, the DBA antenna has a lower profile than the UBA antenna while the UBA antenna outperforms the DBA antenna in realized gain by approximately 1 dB. Meanwhile, the UBA antenna has narrower half-power beam width, which will be beneficial in compact massive multiple-input–multiple-output antenna arrays for improved radiation patterns.

Particle-Velocity Coarray Augmentation for Direction Finding with Acoustic Vector Sensors

In this paper, the problem of passive direction finding is addressed using an acoustic vector sensor array (AVS), which may be deployed either in free space or near a reflecting boundary. Building upon the \(4 \times 1\) vector field measured by an AVS, the particle-velocity coarray augmentation (PVCA) is proposed to admit the underdetermined direction finding using the spatial difference coarray derived from the vectorization of the array covariance matrix. Unlike the widely used spatial coarray Toeplitz recovery technique, the PVCA is applicable to arbitrary array geometries and imposes no reduction of the spatial difference coarray aperture. For the array located at or near a reflecting boundary, the PVCA allows resolving up to 13 sources, while for the array located in free space, the PVCA can identify 9 sources at most. By applying to the systematically designed nonuniform arrays, such as coprime arrays and nested arrays, the PVCA can be coupled with the spatial smoothing technique to get the number of resolvable sources multiplied. Finally, the effectiveness of the PVCA is verified by numerical simulations.

Application of extension rings in thermography for electronic circuits imaging

ABSTRACT Thermographic cameras are often used in areas, where resolutions below 100 µm per pixel are required, as for example in electronics. Such resolutions can be obtained using dedicated lenses. As an alternative, some manufacturers are offering extension rings to be added between the lens and the camera housing, to increase the final image spatial resolution. To test the latter solution and its impact on thermographic temperature measurements, a set of aluminium extension rings was manufactured and mounted in different combinations between an InSb cooled thermographic camera and its lens. Next, the camera, a blackbody IR source, a thick-film resistor on alumina substrate, a microscope reticle calibration glass, and two integrated test circuits were used to investigate the impact of the rings on the temperature measurement accuracy and the achieved spatial resolution. It was demonstrated, that extension rings are a very useful tool in thermography, as long as their impact on the measurement system is taken into account, considering numerical aperture reduction, rings heating by the operating camera, and the cold stop related vignetting. The impact will greatly depend on the specific design of the camera to be used and its lens configuration.

Coupled effects of elastic and plastic deformation on hydraulic properties of the geothermal fracture induced by cyclic loading-unloading processes

Sustainable and profitable energy production from Enhanced Geothermal System (EGS) requires a comprehensive understanding of the coupled effects of elastic and plastic deformation on the hydraulic evolution of geothermal fractures. Four flow-through tests were conducted on granite samples with a rough single fracture at 25–180 °C. Each test was performed on three cycles of loading-unloading processes within a confining pressure of 5–30 MPa. Experimental results indicated that the hydraulic properties are negatively correlated with confining pressure in a logarithmic manner. The coupled effects of elastic and plastic deformation induced by stress loading are the main factor affecting fracture hydraulic properties. Plastic deformation is associated with the mineral grains crush occurring in fracture contacting asperities, which is a permanent and irreversible process. Compared to the results at 25 °C, a larger reduction in permeability is observed at 180 °C, as revealed by a maximum reduction in hydraulic aperture up to >40% at this temperature. This means that larger plastic deformations in the fractures are associated with higher temperatures. Therefore, the addition of proppant is very important for sustainable geothermal development for fractured geothermal reservoirs under high-stress conditions. The ion concentration detection of the effluent solution confirms the existence of free-face dissolution in high-temperature scenarios. Generally, free-face dissolution is beneficial to low-permeability geothermal reservoirs due to its positive effects on fracture hydraulic properties. As the number of loading-unloading cycles increases, the hysteresis effect induced by plastic deformation becomes less and less. Compared to the first loading-unloading stage, the maximum decline of permeability decreases from 73% to 6% and 1% during the second and third stages, respectively. However, pressure dissolution under long-term stress loading should be further investigated, because it may disrupt the self-propping balance of geothermal fracture asperities.

Angle-dependent vignetting stop

We present an approach for reduction of off-axis aberrations of imaging optical systems. The idea is to reduce aperture-dependent off-axis aberrations of optical systems by reduction of the effective aperture of off-axis beams depending on the angle of incidence. The effective aperture of beams is reduced to a greater extent for beams with greater angle of incidence. This is achieved by the use of specific three-dimensional vignetting stop structures, which can be implemented in different ways. These structures work as angle-dependent vignetting stop for the subsequent optical system. This approach can be applied to various optical systems to improve their off-axis optical resolution and extend the usable field of view, without the use of additional optical elements like lenses or mirrors.

The Physiological Response of Different Brook Willow (Salix acmophylla Boiss.) Ecotypes to Salinity.

Few phytoremediation studies have been conducted under semi-arid conditions where plants are subjected to drought and/or salinity stress. Although the genus Salix is frequently used in phytoremediation, information regarding its tolerance of drought and salinity is limited. In the present study, Salix acmophylla Boiss. cuttings from three sites (Adom, Darom and Mea She’arim) were tested for tolerance to salinity stress by growing them hydroponically under either control or increasing NaCl concentrations corresponding to electrical conductivities of 3 and 6 dS m−1 in a 42-day greenhouse trial. Gas exchange parameters, chlorophyll fluorescence and concentration, and water-use efficiency were measured weekly and biomass was collected at the end of the trial. Root, leaf and stem productivity was significantly reduced in the Adom ecotype, suggesting that Darom and Mea She’arim are the more salt-tolerant of the three ecotypes. Net assimilation and stomatal conductance rates in salt-treated Adom were significantly reduced by the last week of the trial, coinciding with reduced intrinsic water use efficiency and chlorophyll a content and greater stomatal aperture. In contrast, early reductions in stomatal conductance and stomatal aperture in Darom and Mea She’arim stabilized, together with pigment concentrations, especially carotenoids. These results suggest that Darom and Mea She’arim are more tolerant to salt than Adom, and provide further phenotypic support to the recently published data demonstrating their genetic similarities and their usefulness in phytoremediation under saline conditions.

Evolution of fracture aperture and thermal productivity influenced by chemical reaction in enhanced geothermal system

Geothermal reservoir scaling controlled by reactive flow is a common phenomenon during geothermal development, which might lead to the decline of geothermal productivity and abandonment of geothermal projects. It is significant to reveal chemical influence on the geothermal reservoir characteristics and production performance to provide the reference for geothermal sustainable development. In this work, a thermal-hydraulic-chemical coupling model is developed for a triple-well fractured enhanced geothermal system considering the silica dissolution and precipitation at the fracture surface. It is focused on the evolution of fracture aperture and geothermal productivity. The results indicate that undersaturated injection will cause mineral dissolution which leads to the rise of fracture transmissibility and a thermal break. The fracture width is enhanced by 0.093 mm, and the permeability is 8 times the initial value after 20-year production. The oversaturated injection will cause mineral precipitation which leads to the reduction of fracture aperture and the increase of pressure difference. The opening is reduced by 0.041 mm and the permeability goes down by 2 orders of magnitude. The maximum increases of average production temperature and differential pressure are 10 °C and 13.5 MPa respectively in the 20th year from undersaturation to supersaturation. Besides, it is figured out that reaction rate denotes the evolution of fracture aperture. Both of them are distributed as a band at a fracture plane, which is determined by saturation index and temperature together. The former controls the reaction pattern (dissolution/precipitation) while the latter controls the reaction speed. Furthermore, the evolution of opening is uneven around the production well at different exploitation stages. Fracture width is higher on the strong side in the first 8.7 years but is higher on the weak side in later development when undersaturated water (0 mol/kg) is injected. The phenomenon can be employed to judge the production status, guide the descaling, etc. Production analysis indicates that oversaturation delays the heat breakthrough and undersaturation reduces the surface pump input. This study will provide a significant reference for the geothermal sustainable production influenced by chemical reactions in an enhanced geothermal system.

A framework to obtain the formulas of the conductivity and aperture of rough fractures under thermohydromechanical conditions

In this investigation, a framework is proposed to find the equations to describe the fracture conductivity and fracture aperture as the functions of effective stress (the difference between geo-stress and fluid pressure), temperature difference (the difference between rock temperature and fluid temperature), and the rock mechanical properties. The framework consists of several lab experiments and a numerical model, which is time-saving to study the influences of the aforementioned influential factors on the fracture conductivity and aperture. After analyzing the lab experimental data, we find that it’s almost impossible to accurately measure the fracture aperture even with high-precision displacement sensors. Therefore, the numerical model coupling the fluid flow in the rough fracture, the solid deformation, and the heat transfer between the hot rock and the injected fluid is built. Three different distributions of the fracture surfaces are analyzed, and we find that the fracture surface roughness fits the normal distribution. After the data matching between the lab experimental data and the numerical results, a large number of numerical experiments using the numerical model are carried out to study the influences of the effective stress, temperature difference and the rock properties, including the elasticity and Poisson's ratio. When fitting the single variable analysis results, we find that the fracture conductivity and aperture are in different function forms of the aforementioned factors. But the reduction of fracture aperture and the natural logarithm of the normalized fracture conductivity can be described using the binary linear function of the effective stress and the temperature difference. Two key strengths of the research lie with the fact that it is time-saving to obtain the exact formulas of fracture conductivity and fracture aperture, and it can measure the dynamic fracture aperture accurately.

An Amur grape VaHsfC1 is involved in multiple abiotic stresses

Plant heat stress transcription factors (Hsfs) belong to a very large gene family and play dominant roles in response to heat stress. Here, we report the functional analysis of VaHsfC1, a class C Hsf gene from Vitis amurensis, and involved in multiple abiotic stresses. The structure of VaHsfC1 contains a typical HSF domain for DNA-binding at N terminus. Phylogenetic analysis revealed that VaHsfC1 belongs to the C1 family of Hsfs. VaHsfC1 was highly induced by heat, cold, exogenous abscisic acid (ABA) and salinity, respectively. Unusually, VaHsfC1was preferentially localized in nucleus, but less in the cytosol. Also, no transcriptional activation was detected for the protein in yeast cells. Ectopic VaHsfC1 expression in Arabidopsis enhanced heat tolerance characterized by the increased survival rate, higher chlorophyll content, reduced electrolyte leakage, and activated expressions of ascorbate peroxidase (Apx2) and heat shock protein (HSP) expression compared to the WT. Interestingly, overexpression of VaHsfC1 in Arabidopsis could also increase the cold tolerance, as reveled from a series changes at the physiological and biochemical steps, as well as at the transcript levels of CORs in the CBF-dependent responsive pathway. Additionally, the growth of VaHsfC1-overexpressing Arabidopsis showed enhanced seed ABA hypersensitivity during germination and cotyledon development, and a significant reduction in stomatal aperture was also observed in overexpression lines. Furthermore, VaHsfC1-overexpressing lines displayed salt-hypersensitive phenotype with a lower rates both in germination and cotyledon greening, and the inhibition of root growth. Our findings demonstrated that the complex nature of VaHsfC1 in mediating multiple abiotic stress responses, as a key component to further understanding of the ‘crosstalk’ mechanism of multiple abiotic stress response in plants.

Impact of Vocal Effort on Respiratory and Articulatory Kinematics

Purpose: The goal of this study was to examine the effects of increases in vocal effort, without changing speech intensity, on respiratory and articulatory kinematics in young adults with typical voices. Method: A total of 10 participants completed a reading task under three speaking conditions: baseline, mild vocal effort, and maximum vocal effort. Respiratory inductance plethysmography bands around the chest and abdomen were used to estimate lung volumes during speech, and sensor coils for electromagnetic articulography were used to transduce articulatory movements, resulting in the following outcome measures: lung volume at speech initiation (LVSI) and at speech termination (LVST), articulatory kinematic vowel space (AKVS) of two points on the tongue dorsum (body and blade), and lip aperture. Results: With increases in vocal effort, and no statistical changes in speech intensity, speakers showed: (a) no statistically significant differences in LVST, (b) statistically significant increases in LVSI, (c) no statistically significant differences in AKVS measures, and (d) statistically significant reductions in lip aperture. Conclusions: Speakers with typical voices exhibited larger lung volumes at speech initiation during increases in vocal effort, paired with reduced lip displacements. To our knowledge, this is the first study to demonstrate evidence that articulatory kinematics are impacted by modulations in vocal effort. However, the mechanisms underlying vocal effort may differ between speakers with and without voice disorders. Thus, future work should examine the relationship between articulatory kinematics, respiratory kinematics, and laryngeal-level changes during vocal effort in speakers with and without voice disorders. Supplemental Material: https://doi.org/10.23641/asha.17065457

Supercritical CO2-Shale interaction induced natural fracture closure: Implications for scCO2 hydraulic fracturing in shales

Multi-stage hydraulic fracturing has been identified as a must to develop shale gas reservoirs by increasing the stimulated reservoir volume (SRV). Supercritical CO2 (scCO2) has been studied as an alternating fracturing fluid due to its tendency to solve numerous problems associated with conventional aqueous based hydraulic fracturing such as formation damage, clay swelling, water scarcity and ground water contamination. However, its consequences to the host rock are not well understood. It has been recognized that scCO2-shale interaction alters the petrophysical properties during the long-term exposure of shale into scCO2, far little attention has been paid to understand the impact of this process for the short term. Thus, laboratory fracturing experiments using scCO2 on cubic shale samples (50 × 50 × 50 mm) in true triaxial stress cell (TTSC) were conducted. X-ray computed tomography (CT) imaging and low-pressure N2 adsorption were also performed to gain a deeper understanding of the fluid-rock interactions on the studied shales at a short-time process. Post-fracturing x-ray CT scans revealed a significant reduction, in the range of 14% to 46%, in the aperture of the natural fractures, indicating towards a possible scCO2 induced swelling. Mechanical compression test on the sample results in around 12% reduction in the fracture aperture, ruling out the possibility of confining stress being the key factor behind the fracture closure observed during fracturing. scCO2 soaking and N2 adsorption experiments showed the narrowing down of the macropores after scCO2 treatment implying the adsorption swelling as one of the controlling factors for the reduction of fracture aperture. Taken together, our results suggest that scCO2-shale interactions during the short term process of hydraulic fracturing can contribute to decreasing the conductivity of pathways between matrix and hydraulic fractures and hence adversely affecting the post-fracturing productivity of the rock.

Effect of vapor pressure deficit on the photosynthesis, growth, and nutrient absorption of tomato seedlings

Vapor pressure deficit (VPD) is the main driving force of plant water transport and affects the nutrient absorption of plants. Exploring the nutrient absorption, growth, and photosynthetic characteristics of different tomato cultivars under different VPDs is of great importance for the cultivation of tomato. This experiment featured two levels of VPD (high 2.2/low 0.9 kPa) and two tomato cultivars (Solanumlycopersicum L., cv. Jinpeng and cv. Zhongza) for a total of four treatments in two controlled environment growth chambers. After about 4 weeks, the seedlings (at the three true-leaf stage) were transplanted into pots flled with inorganic medium and watered with nutrient solution. The stomatal characteristics, leaf moisture status, net photosynthetic rate (An), and plant growth of Jinpeng were not significantly different under the two VPD treatments, but high VPD resulted in a significantly increased transpiration rate (E) and whole plant hydraulic conductance (Kplant), as well as significantly increased absorption of potassium (K) and calcium (Ca) in various organs. In contrast, Zhongza had lower biomass, smaller stem height, and lower total leaf area under high vs. low VPD conditions. At high VPD, the reduction of photosynthesis in Zhongza was mainly caused by anatomical modifications of the stomata; significant reductions in stomatal aperture and length restricted photosynthesis and biomass accumulation. Moreover, the E and Kplant of Zhongza were reduced by stomatal state changes that prevent excessive transpiration. High VPD limited plant transpiration and mass flow of water, which reduced the absorption and accumulation of nutrients. Overall, these results suggest tomato cultivars differ in their stomatal sensitivity. Specifically, increasing VPD resulted in increased levels of some nutrients in certain organs in the cultivar with lower stomatal sensitivity; however, the cultivar with higher stomatal sensitivity demonstrated opposite trends.

Modeling the orientation- and stress-dependent permeability of anisotropic rock with particle-based discrete element method

A novel physics-based numerical model is proposed to simulate the orientation and effective confining pressure dependent permeability of anisotropic rock . In the two-dimensional discrete element model, presence of anisotropy is explicitly represented by inserting a set of smooth joints. Based on the experimentally obtained effective stress law at sample scale, a physics-based relation is deduced to describe the reduction of pipe aperture upon the normal contact force at grain scale. Darcy test is conducted to validate the model by comparing the flow rate and pressure distributions with analytical solutions. Different parameters are assigned to represent the difference in flow capacity of rock matrix and beddings. Fluid flow tests performed on the isotropic model and anisotropic models with horizontal and vertical beddings reveal that the macro permeability decreases with increasing effective stress, following the same effective stress law. The initial aperture dominates the intrinsic permeability while the reduction of permeability is due to the closure of pipe aperture. Permeability anisotropy is caused by the different apertures assigned to the rock matrix and the bedding while the force sensitivity factors determine the stress-dependence of the permeability anisotropy. Simulations of the stress concentration and fluid dissipation around borehole confirm the capacity of the model in capturing the hydro-mechanical coupled responses of anisotropic rock formation. This study provides a fluid flow model for the exploration of mechanisms underlying the orientation and stress dependent permeability of anisotropic rocks and for the simulation of their engineering responses subjected to hydro-mechanical coupling.

Eyes wide shut: necessity and effect of adjunctive procedures after decompression surgery in patients with endocrine orbitopathy

BackgroundOrbital decompression surgery is frequently the last therapeutic measure in the surgical treatment of endocrine orbitopathy (EO). Additional rehabilitative and corrective surgical treatments are often used to improve the resulting eyelid stigmata, such as an increased lid aperture and scleral show. The aim of the study was to evaluate the effect of adjunctive surgical procedures after orbital decompression surgery in patients with EO.MethodsA total of 120 orbitae from 65 patients with EO from 2010 to 2020 at a tertiary care center in Germany were retrospectively evaluated. Ocular surface area (OSA) and vertical palpebral fissures were three-dimensionally analyzed at the following stages: presurgical decompression, postsurgical decompression, and post-adjunctive surgical procedures. For the analysis of vertical palpebral fissures, predefined vertical line distances were measured on the upper and lower lids in the central, medial, and lateral pupillary regions.ResultsThe initial OSA was 2,98 ± 0.85 cm2, and it decreased significantly after decompression surgery to 2.52 ± 0.62 cm2. After adjunct surgical procedures, OSA further decreased to 2,31 ± 0,55 cm2. Furthermore, a statistically significant reduction in all pupillary parameters was noted after each treatment step. More lid-lengthening procedures were performed on the lower lid than on the upper lid. Canthoplasty (n = 13) was the most frequently performed procedure during rehabilitation.ConclusionSurgical decompression surgery improves OSA and leads to a significant reduction in lid aperture. Adjunctive surgical procedures, addressing the upper and lower lid, have a significant influence on the ongoing clinical course and contribute to a reduction in OSA.

An experimental investigation of the effect of long-term, time-dependent proppant embedment on fracture permeability and fracture aperture reduction

The inability to achieve satisfactory production targets from unconventional oil/gas deposits is a foremost concern for many hydraulic fracturing projects. One potential reason for recovery difficulties is the lack of a clear understanding of the severity of proppant damage mechanisms in fractures exposed to extreme reservoir environments. In this comprehensive laboratory-scale experimental analysis, we evaluate the significance of one such proppant damage mechanism: proppant embedment , which occurs in fractures over extended time frames, and its ultimate effect on fracture permeability and the reduction of fracture aperture . The results reveal that a significant reduction of fracture permeability occurred after only 36 h of exposure to confining stresses in uniformly (49%) and partially (29%) proppant-distributed fractures. Importantly, by 144 h, permeability reductions of 92.3% and 54.6% were observed for uniformly- and partially-distributed fractures. However, improved permeability results were obtained for multilayer proppant-distributed fractures. The effect of creep-induced proppant embedment was comprehensively studied. In uniformly and partially proppant-distributed specimens, both elastic and creep deformation dominate the embedment process. However, in multilayer proppant-distributed fractures, the embedment process is predominantly governed by the initial elastic embedment mechanism. CT scanning of uniformly and partially proppant-distributed fractures confirmed the substantial reduction in fracture aperture due to proppant embedment combined with fracture asperity damage. Nevertheless, CT scanning revealed only a minor degree of proppant embedment in multilayer proppant-distributed fractures, although significant proppant-re-arrangement occurs in multilayer proppant packs under high-stress conditions. Importantly, for both following scenarios: (1) high confining pressures (30 MPa) at lower testing times (12 h), and (2) low confining pressures (20 MPa) at longer testing times (144 h), the impact of the presence of either a uniform or partial proppant arrangement is minimal, as both proppant arrangements lead to significantly lower fracture permeability and aperture.