Rate Of Ingress Research Articles

Analysis of water ingress, grouting effort, and pore pressure reduction caused by hard rock tunnels in the Oslo region

Many subsurface projects in Scandinavia face challenges with settlement risk from water ingress into tunnels, due to challenging ground conditions featuring hard bedrock underlying soft, marine clay deposits. Pore pressure reduction in these clay-filled depressions can cause damage to nearby buildings and is one of the main risks associated with infrastructure development in Oslo. This paper presents an extensive database from 44 tunnels in the Oslo region, constructed between 1975 and 2020. The data consists of measured water ingress after pre-excavation grouting, reduction in pore pressure, pre-excavation grouting effort, and geological parameters. The data is analysed to identify trends and relations between key parameters, such as expected pore pressure reduction for a given water ingress rate and necessary grouting effort to obtain a given hydraulic conductivity of the grouted zone. The analysis shows that it is necessary to focus on pore pressure monitoring in future projects, rather than water ingress, to reduce the risk of unacceptable pore pressure reduction. Suggestions are given on how to optimise monitoring and follow-up of pre-excavation grouting to ensure that required watertightness is met.

Influence of invasive crayfish on fine sediment transport, ingress and bed storage in lowland rivers

AbstractHistorically it has been assumed that abiotic forces dominate fluvial sediment dynamics. However, a growing body of work indicates that biological energy can also exert a significant control over sediment dynamics. The role that invasive species may play in altering fine sediment dynamics is particularly pertinent given that any influence may disrupt the natural equilibrium of the ecosystem. Here we investigated the effect of invasive signal crayfish (Pacisfastcus leniusculus) on the transport and storage of fine sediment in a densely populated river compared with a nearby control river without crayfish, over an 18‐week period. We observed clear evidence of diurnal fluctuations in turbidity associated with crayfish presence including periodograms with power peaks at a period of 1 day. Fine sediment fluxes indicated that crayfish contributed on average 18.5% extra to baseflow loads than would be likely under abiotic forcing alone. Temporal variations in suspended sediment concentrations were also observed at the control site but these were different in character and exhibited no clear temporal pattern or consistency as confirmed by periodogram analysis. Crayfish did not have an effect on sediment ingress rates relative to the control site and, at the crayfish site, the reach scale sediment budget was in net equilibrium during the sampling period. Our results provide further evidence that biological energy alters riverine fine sediment dynamics and warrants consideration in sediment dynamic models.

Influence of Textile Structure on the Hygroscopic Behavior of Bamboo Textile-Reinforced Polymer

ABSTRACT Although bamboo fiber-reinforced polymer has been extensively studied, its utilization has been limited by its unfavorable performance. This study developed a non twisting bamboo textile-reinforced polymer (BTRP) through vacuum resin transfer molding and then used two weaving methods, different layers, different edge treatments, two stacking sequences, and two sizes as factors to investigate the effect of woven structures on the hygroscopic behavior of BTRP, such as water absorption, diffusion, dimensional stability, and moisture transportation. The differences in the results of long-term immersion and the swelling at different locations of BTRP were also examined. The results of this study indicate that the weaving method directly affected the water absorption from the fiber area and that the size of the specimens affected the saturation rate. The swelling behavior differed with the weaving method and number of layers, which indicates that rate of water ingress and transverse fiber swelling were the reasons that cause the different swelling behavior. This study found that moisture may be transferred differently through different parts of BTRP due to variations in fiber saturation. Moreover, the analysis of the center and periphery of BTRP specimens indicated that textile structure significantly affected water uptake and indirectly caused two moisture transport mechanisms.

Near-infrared fluorescence imaging during ex vivo lung perfusion: Noninvasive real-time evaluation of regional lung perfusion and edema

ObjectiveEx vivo lung perfusion (EVLP) is an excellent platform to evaluate donor lung function before transplantation, but novel methods are needed to accurately confirm transplant quality. Near-infrared fluorescence (NIRF) imaging with indocyanine green (ICG) has been used in various clinical perioperative applications to evaluate tissue perfusion. We used NIRF imaging during pig and human EVLP to evaluate donor lung perfusion and edema. MethodsPig lungs with various degrees of lung injury (n = 10) and human lungs rejected from clinical transplantation (n = 3) were imaged during EVLP using intravascular ICG and a SPY Elite (Stryker) NIRF imaging unit. Optimal ICG and imaging conditions, and perfusion and edema quantification methods, were established. Pig lung transplants with extended graft preservation (n = 5) and control native lungs (n = 6) were also imaged. ResultsA single ICG dose resulted in sustained donor lung NIRF throughout the EVLP. Even and homogenous ICG signal was demonstrated in areas of normal lung. Low NIRF was present in regions with poor tissue perfusion, and rapid, intense ICG accumulation occurred in damaged and edematous areas. Segmental perfusion defects were common in the peripheral and elevated regions of the lungs, and serial imaging showed gradual perfusion recovery during EVLP. Impaired microvascular reperfusion, indicated by a decreased NIRF ingress rate, was detected in transplanted pig lungs early after reperfusion. ConclusionsNIRF imaging enables noninvasive real-time evaluation of lung perfusion and edema during EVLP. Prospective clinical studies are needed to determine the role of NIRF imaging in donor lung assessment and selection, and prediction of posttransplant outcomes.

MOLECULAR CONFIRMATION OF TWO HONEYBEE SPECIES (Apis mellifera L. and A. cerana F.) IN APIARY AND THEIR FORAGING BEHAVIOR IN LITCHI ORCHARD

The foraging of honeybees is one of the most well-organized and admirable behaviors that exists among social insects and being greatly influenced by nectarine sources and habitat adaptability. In Bangladesh, apiculture is mostly confined to rearing of European honeybee Apis mellifera L. despite of having the native A. cerana F. due to lack of information about comparative foraging efficiency and productibility of two species in Asian cropland ecosystem. The present study aimed to molecular characterization of two honeybee species in apiary and their foraging performance on litchi orchard. The genetic identity was revealed thorough phylogenetic analysis with >90% bootstrap value using mitochondrial cytochrome oxidase sub unit- 1 (CO1) gene and nucleotide sequence data deposited to NCBI GenBank with accession number ON680900- ON680902 for A. mellifera and ON703291-ON703293 of A. cerana. Upon placing the identified bee hives in litchi orchard, the foraging efficiency were studied based on egression and ingression rate, number of bees visited flowers per minutes, and nectar and pollen collection efficiency in varied time series of the day. Principal component analysis (PCA) for measuring the contribution of different foraging parameters and the species wise PCA biplot revealed the better foraging efficiency by A. mellifera L. compared to A. cerana F. in litchi blooms. However, foraging efficiency of other nectarine sources should be analyzed for suggesting best performing bee species in apiculture.

OVERCROWDING IN INDIAN PRISONS: DURING PRE COVID-19 AND ONGOING PANDEMIC

The Prison administration in India usually faces several challenges in prison management even during the normal times. These challenges got aggravated during the ongoing pandemic COVID-19. One of the main challenges has been the overcrowding in prisons in India. The Supreme Court of India (SC) took suo-moto cognizance of the issue of overcrowding in prisons during the pandemic and considered the situation that the prison inmates were at a high risk of transmission of COVID-19 virus due to the high rate of ingress and egress, in prisons. Thus, the Supreme Court directed the state governments to constitute a High Power Committee (HPC) and identify the prisoners including undertrials who could be released on interim bail or parole. The authors of this research paper have undertaken a study of the issue of overcrowding in Indian prisons in pre COVID-19 times and finding out if the overcrowding actually reduced in the last one year during the ongoing pandemic in view of the SC order. The authors have also explored and an alysed the reasons behind such high overcrowding in India Prisons and have made some suggestions to overcome these in future.

Deformations in Cement Pastes during Capillary Imbibition and Their Relation to Water and Isopropanol as Imbibing Liquids.

The traditional approach for evaluating capillary imbibition, which describes the phenomena as a linear relationship between mass gain and the square root of time, considers a rigid pore structure. The common deviation from the linearity when using the square-root law (manifested in a downward curvature, i.e., slower water ingress) can be explained by considering a changing pore structure during the process caused by the swelling of calcium silicate hydrate (C-S-H) during water ingress. Analysing how the combination of deforming phase (C-S-H), non-deforming phase, and porosity affects the capillary water ingress rate is relevant for a deeper understanding of concrete durability. In this research, the C-S-H content was quantified by means of XRD diffraction coupled with Rietveld + PONKCS, dynamic water sorption (DVS), and SEM/BSE images coupled with phase mapping using PhAse Recognition and Characterization (PARC) software. The porosity was assessed by mercury intrusion porosimetry, water absorption under vacuum, and DVS. Furthermore, to assess deformations occurring with water and a non-aqueous imbibant, capillary imbibition tests with water and isopropanol as invading liquids were performed along with simultaneous deformation measurements. The relation between the relative C-S-H content and porosity has a great impact on the transport process. Samples exposed to isopropanol presented a much larger liquid uptake but significantly fewer deformations in comparison to imbibition with water. The effects of the changing pore structure were also evaluated with the Thomas and Jennings model, from which calculations indicated that pore shrink during imbibition. A comprehensive description of the relation between deformations and capillary imbibition in cement pastes reveals that liquid ingress is highly influenced by deformations.

Optogenetic relaxation of actomyosin contractility uncovers mechanistic roles of cortical tension during cytokinesis

Actomyosin contractility generated cooperatively by nonmuscle myosin II and actin filaments plays essential roles in a wide range of biological processes, such as cell motility, cytokinesis, and tissue morphogenesis. However, subcellular dynamics of actomyosin contractility underlying such processes remains elusive. Here, we demonstrate an optogenetic method to induce relaxation of actomyosin contractility at the subcellular level. The system, named OptoMYPT, combines a protein phosphatase 1c (PP1c)-binding domain of MYPT1 with an optogenetic dimerizer, so that it allows light-dependent recruitment of endogenous PP1c to the plasma membrane. Blue-light illumination is sufficient to induce dephosphorylation of myosin regulatory light chains and a decrease in actomyosin contractile force in mammalian cells and Xenopus embryos. The OptoMYPT system is further employed to understand the mechanics of actomyosin-based cortical tension and contractile ring tension during cytokinesis. We find that the relaxation of cortical tension at both poles by OptoMYPT accelerated the furrow ingression rate, revealing that the cortical tension substantially antagonizes constriction of the cleavage furrow. Based on these results, the OptoMYPT system provides opportunities to understand cellular and tissue mechanics.

The role of environmental conditions on the carbonation of an alkali-activated cementitious waste form

Cast Stone is a cementitious waste form being considered for the solidification of low activity waste at the DOE Hanford Site. Under near-surface disposal conditions in an arid environment, Cast Stone is subject to drying and carbonation which may impact retention of waste constituents. This study investigates the effects of environmental CO2 concentration and relative humidity (RH) on the carbonation of Cast Stone. The rate of carbonation front ingress and the extent of carbonation reaction were characterized for samples aged up to 48 weeks at three RH levels and two CO2 concentrations. While the 68% RH environment allowed the greatest reaction extent, the 15% RH environment yielded the deepest carbonation front ingress. At 68% RH, there was a linear relationship between the ingress rate and CO2 concentration. Carbonation reactions increased the drying rate of Cast Stone. Redistribution of sodium toward the wetting front was observed under drying and carbonation conditions.

Predicting Clinical Outcomes in a Diabetic Foot Ulcer Population Using Fluorescence Imaging.

To retrospectively evaluate a cohort of patients with diabetic foot ulcers to determine if the rate of microcirculatory flow detected by fluorescence imaging within the wound and surrounding tissue is associated with healing outcomes. Tissue perfusion parameters used for the current analysis were the ingress rate (IR) within the wound bed (R01) and in an area remote from the wound (REF), as well as time to first blush. Wounds were then categorized based on their outcome (healed, healing, chronic nonhealing, partial foot amputation, proximal amputation below the knee) and compared between patients with positive or negative wound healing outcomes. The final study cohort included 61 wounds and demonstrated that a higher IR within R01 and REF areas was significantly associated with positive outcomes, whereas time to first blush was not. A two-predictor logistic model found a significant relationship between IR (R01 and REF) and odds of wound healing. Fluorescence imaging evaluation of a diabetic foot ulcer can provide valuable information on healing outcomes that can help determine if a wound is progressing toward healing and therefore may help inform the need for advanced wound modalities, referrals, and amputation.

Perfusion Patterns in Patients with Chronic Limb-Threatening Ischemia versus Control Patients Using Near-Infrared Fluorescence Imaging with Indocyanine Green.

In assessing the severity of lower extremity arterial disease (LEAD), physicians rely on clinical judgements supported by conventional measurements of macrovascular blood flow. However, current diagnostic techniques provide no information about regional tissue perfusion and are of limited value in patients with chronic limb-threatening ischemia (CLTI). Near-infrared (NIR) fluorescence imaging using indocyanine green (ICG) has been used extensively in perfusion studies and is a possible modality for tissue perfusion measurement in patients with CLTI. In this prospective cohort study, ICG NIR fluorescence imaging was performed in patients with CLTI and control patients using the Quest Spectrum Platform® (Middenmeer, The Netherlands). The time–intensity curves were analyzed using the Quest Research Framework. Fourteen parameters were extracted. Successful ICG NIR fluorescence imaging was performed in 19 patients with CLTI and in 16 control patients. The time to maximum intensity (seconds) was lower for CLTI patients (90.5 vs. 143.3, p = 0.002). For the inflow parameters, the maximum slope, the normalized maximum slope and the ingress rate were all significantly higher in the CLTI group. The inflow parameters observed in patients with CLTI were superior to the control group. Possible explanations for the increased inflow include damage to the regulatory mechanisms of the microcirculation, arterial stiffness, and transcapillary leakage.

Chloride ingress rate and threshold content, as determined by the ‘Integral’ test method, in concrete with several w/c ratios in saturated and unsaturated conditions

The ‘integral’ test method aims at the simultaneous determination of the chloride migration rate and chloride threshold content. This information is required for durability performance design of reinforced concrete structures in the marine environment. Standard tests are generally designed to be applied on saturated samples to improve their repeatability and reproducibility, but this condition differs from the actual conditions of depassivation in structures in service. This paper compares results of the ‘integral’ test method applied on concrete made with ordinary Portland cement and a water-to-cement ratio ranging 0.35–0.50, preconditioned for full saturation and a saturation degree of 77%. Results are contrasted with concrete properties commonly associated with its performance concerning chloride ingress. The variation in the saturation degree in the range 77–100% showed a greater effect on the chloride ingress rate than in the chloride threshold content. The determined chloride threshold decreases with increasing w/c ratio.

EXPERIMENTAL STUDY ON THE RATE OF ABSORPTION OF WATER OF BASALT, POLYPROPYLENE, AND STEEL FIBERS REINFORCED CONCRETE

Good durability of concrete is an essential part of the design process, and tests to determine sustainability have been developed for both laboratory and site use. The main feature of durable concrete is low water absorption. Almost all forms of deterioration in reinforced concrete involve deleterious fluid ingress through the concretes pore structure. In wet concrete, the water ingress rate or other liquids is mostly controlled by absorption due to capillary rise. This study examines the effect of basalt, polypropylene, and steel fiber in different volume fractions at 0.3%, 0.6%, and 0.9% for absorption tests. A total of 8 specimens for different fiber were examined based on the rate of water absorption test recommended by ASTM C1585-04. A result obtained has been analyzed and compared with the control specimen. A relationship between absorption rate and the square root of time for both concrete mixtures was represented graphically and linearly. Result data showed a precise decrease in absorption due to incorporating both types of fiber. Also, from the result data, basalt and polypropylene showed greater uptake than steel fiber and enhances mass transport of water into concrete specimens. However, steel fiber addition showed high resistance to absorption rater than the control specimen and other fiber.

Performance-Based Approach for Deciding the Age of New Concrete for Thin Epoxy Overlay Application

A thin epoxy overlay application is a capital preventive maintenance activity. Epoxy overlays reduce the rate of chloride ion ingress and extend bridge deck service life. Highway agency policies and manufacturer specifications require maintaining a 28-day curing period (7-day wet and 21-day dry curing) before the application of an epoxy overlay on bridge decks requiring new concrete for patches and repairs. Consequently, the contractors wait for 28 days to apply an epoxy overlay. Delaying application time increases project completion time and the cost of construction and mobility. The suitability of new concrete to receive epoxy overlays and the performance of overlays depend on several parameters including concrete strength, moisture, and tendency to crack. Such parameters depend on concrete mixture ingredients and wet and dry curing periods. This paper presents a performance-based procedure for evaluating the possibility of reducing the 28-day waiting period for a thin epoxy overlay application on new concrete. An experimental program was developed and executed to evaluate the impact of epoxy overlay application parameters and overlay performance using a tensile bond pull-off strength test. The results support developing a performance-based procedure for deciding on the suitable age of new concrete to receive a thin epoxy overlay. The pull-off bond strength of epoxy overlays applied at 7, 14, and 21 days, following a 7-day moist curing, shows the possibility of applying an epoxy overlay before the end of the 28-day curing period stipulated in the current specifications.

Effect of curing regimes on chloride binding capacity of geopolymer

Chloride attack on reinforced concrete is considered the most important aspect in concrete durability investigation. This study is carried out to investigate effect of curing condition on the chloride binding capacity of fly ash geopolymer pastes containing a range of cast in chloride contents (NaCL), varying from 1%, 2% and 4% by mass of binder. The applied curing regimes were normal, oven, steam and microwave. The impact of induced chlorides on the compressive strength and on the chloride binding capacity of fly ash geopolymers under different curing conditions is determined. A detailed microstructure and phase composition analysis were conducted through SEM and XRD tests. It was observed that applying thermal curing conditions could increase the chloride binding capacity to the formed geopolyric hydration product. High curing temperatures promote the precursor dissolution reactions and will increase the overall generation of polymerization reaction products, while under normal curing a lot of fly ash grains did not fully react. Therefore, thermal curing is important in the activation of geopolymerization process that increase aluminosilicate gel and result in dense and less porous geopolymer matrix and yields in high compressive strength. This results in the physical adsorption and chemical binding of chloride ions on the gel surface, and hence reducing the rate of chloride ingress. It was concluded that the ingress of chlorides can be particularly controlled better through binding the free chloride ions under steam and microwave curing in the fly ash geopolymer concrete.

Multibody approach for reactive transport modeling in discontinuous-heterogeneous porous media

In the context of long-term degradation of porous media, the coupling between fracture mechanics and reactive transport is investigated. A reactive transport model in a cracked discontinuous and heterogeneous porous medium is proposed. The species transport through and along the crack network are taken into account in a multibody approach. A dedicated geochemistry solver is developed and allows to take into account a significant number of chemical reactions. The model is validated via a benchmark for a porous medium without discontinuity. The applications deal with two kinds of chemical attacks in a pre-cracked concrete sample and highlight the impact of the discontinuities in the reactive transport kinetic and on the localization of the chemical degradation. The results bring out that a unidirectional descriptor, such as the depth of ingress rate, is not sufficient to describe the material degradation correctly.

Approximate Model-based State Estimation in Simplified Receding Horizon Control

Multiple variable systems often have to be so controlled that in the lack of appropriate sensors no satisfactory information is available for the complete estimation of their state variables. Normally only their certain components are kept under observation and control, while the other ones evolve according to the consequences of the exerted control signal. In control-based treatment of patients suffering from "Type 1 Diabetes Mellitus (T1DM)", the only directly measured quantity is the subcutaneous glucose concentration in the blood controlled by a single control signal, the insulin ingress rate. The applied model may use several components in the state variable. The traditional "Receding Horizon Controller (RHC)" requires the estimation of the complete state variable for the calculation of the control signal. In this paper preliminary simulations are persented in which the operation of the RHC is studied in the control of two vertically connected, oscillating masspoints so coupled by springs that only the state of the upper one is observed and directly controlled. Instead sensor-based observations, the lower point’s coordinate is calculated by the use of an available "rough" model. Preliminary calculations were made for a particular human glucose-insulin model, too. In the implementation of the RHC special simplifications were introduced. In our further work we wish to apply this method for investigating various T1DM treatment models.

The chloride-induced corrosion of a fly ash concrete with nanoparticles and corrosion inhibitor

The urge to reduce the carbon footprints from cement production warrants the development of more sustainable approaches in the construction industry. Towards this, the long term corrosion resistance of the embedded steel rebar in a novel ternary-blended reinforced concrete system with 56 wt% Ordinary Portland cement (OPC), 40 wt% fly ash, 2 wt% nanomodifiers, and 2 wt% corrosion inhibitor (referred to as CFNI) was studied by chemical and electrochemical tests in a simulated chloride environment for 180 days. The performance was compared with three other concrete systems (CC (100% OPC), CF (60 wt% OPC and 40 wt% fly ash) and CFN (58 wt% OPC, 40 wt% fly ash and 2 wt% nanomodifiers). The electrochemical results indicated a significant enhancement in the corrosion resistance of steel in the CFNI concrete as compared to other systems. A five times higher value of polarization resistance (Rp) is obtained in CFNI, as compared to the control concrete, indicate the better resistance of CFNI. Further, in CFNI specimen, the chloride ingress rate was significantly lower and the Field Emission Scanning Electron Microscopy (FESEM) images showed no microcracks or pores at the corroded concrete-steel interface of CFNI specimens. The apparent diffusion coefficient (Dcl) of the concrete system was determined using the bulk diffusion test and chloride profiling. The value of Dcl for CFNI concrete was found to be one order less in magnitude than other concrete specimens, indicating the enhanced resistance against chloride attack. These results show that CFNI concrete is a promising ternary-blended concrete mix to achieve long corrosion-free service life for the structures in aggressive chloride environments.

Terahertz pulsed imaging as a new method for investigating the liquid transport kinetics of α-alumina powder compacts

Investigating the liquid transport kinetics of solid catalysts is of great importance for gaining a better understanding of the manufacturing and performance of such catalysts during reaction upon contact with the liquid. Terahertz pulsed imaging (TPI) coupled with a newly designed flow cell was used to quantify the rate of water ingress into α-alumina pellets with a range of different porosities. A wide range of compaction forces (cold compaction, 7–58kN) and sintering conditions (no firing and sintering at 1200 and 1300°C) was investigated to explore the optimal pellet microstructure, i.e. mechanically strong but sufficiently porous for fast liquid transport kinetics. The results confirm that both the microstructure characteristics, particularly porosity, as well as the surface properties, i.e. wettability, influence the liquid transport kinetics. Fitting the TPI penetration rates with a power law shows that the type of observed mass transport characteristics is consistent with Darcy flow. The Lucas–Washburn equation was used to calculate the hydraulic radius based on the transport data. In summary, the results demonstrate that TPI has great potential to study the liquid transport kinetics of porous ceramic catalysts and catalyst supports and that can comfortably quantify transport processes at rates of 250μms−1 and beyond in such substrates for better quality control and optimised design and performance of such materials.

Stability of GFRP composites with varied fractions of reinforcement exposed to ageing processes outdoors

The effects of outdoor ageing on various compositions of glass fibre reinforced plastic (GFRP) composites were studied. Changes in the interlaminar shear strength (ILSS) of hand-laid samples with 50–60 wt.% of fibre were determined by three-point bending and glass transition temperature (Tg) measurements. SEM analysis was carried out for exploring the mode of failure. The moisture ingress rate and extent were concentration-dependent at first, but became increasingly dependent on the fibre-matrix interfacial area. The ILSS initially fluctuated and then showed a decreasing trend with time, especially for the higher fibre concentrations. ILSS variations were zigzag initially and showed a lowering trend after the initial periods. Rate of lowering of ILSS was the highest for samples with the highest fraction reinforcement. Weight fraction reinforcement didn’t have any significant effect on the Tg variations. SEM fractograph revealed excessive fracture and fragmentation for the composite samples with the highest weight percentage reinforcement.