Successive Discharges Research Articles

The boost of force in unfused tetanic contractions at variable interpulse intervals in fast motor units of the rat medial gastrocnemius

Previously, boost and sag effects seen in unfused tetanic contractions have been studied exclusively at constant stimulation frequency. However, intervals between successive discharges of motoneurons vary during voluntary movements. We therefore aimed to test whether the extra-efficient force production at the onset of contraction (boost) occurs during stimulation with variable intervals, and to what extent it depends on the level of interpulse interval (IPI) variability and history of stimulation. Four sets of three repeated unfused tetani (the first set with constant IPIs at 35 Hz; the other three sets with mean frequency 35 Hz and variable IPIs 28 ± 2 ms, ± 5 ms, and ± 7 ms, respectively) were recorded with 3 min breaks in fast fatigable and fast fatigue-resistant motor units of the rat medial gastrocnemius. We show that boost occurred in the first tetanic contraction of each set for stimulation at both constant and variable IPIs in two fast types of motor units; additionally, it was present in different IPIs variability for a given range. Mathematical decomposition of first (sagging) and second (non-sagging) tetanic contractions into twitch-like responses to successive stimuli in the tested IPIs variability showed that the changes underlying boost are pattern independent. This implies that boost probably occurs in daily activity when motoneurons fire with an unstable firing rate. The effect may therefore contribute to the development and regulation of force in voluntary daily activities, especially in short powerful contractions.

Suicide Attempt by Successive Nail Gun Discharges to the Head and Chest: A Case Report

As firearms are frequently used in suicide attempts, there is wide recognition of this potential danger with restrictions and barriers present in many jurisdictions to limit the purchase and possession of firearms. However since nail guns were introduced in the 1950s, nail gun discharge (NGD) injuries have been an increasing phenomenon due to more widespread availability and ease of use without restrictions on possession. Although existing literature has described suicide attempts by NGD to single body sites, reports of injuries to multiple body sites are rarer. In this case report, we present the case of a patient who survived multiple, severe, self-inflicted penetrating wounds secondary to a suicide attempt by NGD. Through this case report, we aim to identify future opportunities to tailor aspects of risk assessment for patients who may have occupational access to tools such as nail guns, as this should be a consideration when screening for risk and safety planning. [ Psychiatr Ann . 2023;53(11):525–527.]

Construction of Binder-Free, Self-Supported, Hetero-Core-Shell Honeycomb Structured CuCo2 O4 @Ni0.5 Co0.5 (OH)2 with Abundant Mesopores and High Conductivity for High-Performance Energy Storage.

Clever and rational design of structural hierarchy, along with precise component adjustment, holds profound significance for the construction of high-performance supercapacitor electrode materials. In this study, a binder-free self-supported CCO@N0.5 C0.5 OH/NF cathode material is constructed with hierarchical hetero-core-shell honeycomb nanostructure by first growing CuCo2 O4 (CCO) nanopin arrays uniformly on highly conductive nickel foam (NF) substrate, and then anchoring Ni0.5 Co0.5 (OH)2 (N0.5 C0.5 OH) bimetallic hydroxide nanosheet arrays on the CCO nanopin arrays by adjusting the molar ratio of Ni(OH)2 and Co(OH)2 . The constructed CCO@N0.5 C0.5 OH/NF electrode material showcases a wealth of multivalent metal ions and mesopores, along with good electrical conductivity, excellent electrochemical reaction rates, and robust long-term performance (capacitance retention rate of 87.2%). The CCO@N0.5 C0.5 OH/NF electrode, benefiting from the hierarchical structure of the material and the exceptional synergy between multiple components, demonstrates an excellent specific capacitance (2553.6 F g-1 at 1 A g-1 ). Furthermore, the assembled asymmetric CCO@N0.5 C0.5 OH/NF//AC/NF supercapacitor demonstrates a high energy density (70.1Wh kg-1 at 850W kg-1 ), and maintains robust capacitance cycling stability performance (83.7%) after undergoing 10000 successive charges and discharges. It is noteworthy that the assembled supercapacitor exhibits an operating voltage (1.7V) that is well above the theoretical value (1.5V).

A Silica Capillary-Based Sensor with Access Channels for the Simultaneous Measurement of Pressure and Temperature

A hybrid fiber sensor for the simultaneous measurement of pressure and temperature is proposed. The sensor is constituted of a section of silica capillary tube (SCT) whereat access channels are created with two different methods: instilling a bubble on the fiber by employing successive arc discharges on the SCT whilst under pressure and splicing the SCT with another section of SCT with a smaller inner diameter. The reflection-based sensor enhances Fabry–Perot interference (FPI) and antiresonant (AR) guidance, simultaneously, in a single sensing element of a few millimeters. A comparison study between the access channel methods reveals higher spectral visibility for the bubble method and similar pressure and temperature resolutions. For a 2.58 mm long sensor with a bubble, the sensitivity to pressure is 4.09 ± 0.01 nm/MPa and −3.7 ± 0.1 nm/MPa for the FPI and AR, respectively, while its sensitivity to temperature is −0.20 ± 0.02 pm/°C and 24.0 ± 0.5 pm/°C, respectively, for the FPI and AR, which are within the numerically calculated sensitivities. The sensor is robust and has a convenient reflective probe with easy and low-cost fabrication, granting high competitiveness in actual applications.

Electrical discharge machining assessment of AA7075/Rice Husk Ash composite using response surface methodology

This study aims to explore electrical discharge machining of green AA7075 composite supplemented with rice husk ash (an agricultural waste) using response surface methodology. Central composite rotatable design for three factors – current, pulse duration and gap voltage – was used for carrying out machining experiments. The effect of these input parameters was evaluated on performance parameters including material removal rate, tool wear rate and surface roughness. Regression models are developed for each response, and model adequacy was checked using the analysis of variance technique. Furthermore, Pareto charts for the standardized effects, normal probability distribution plots, residuals vs fits plots, residual vs order plots, main effect plots and contour plots were also developed for output parameters. Peak current was found to be the major process parameter affecting every response variable. The influence of other linear, squared and interaction effects that are found to be significant for each response are discussed. Multi-response optimization for different process parameters using the composite desirability approach is also highlighted. Confirmatory experiments at optimum process parameters are carried out to analyze variations in predicted values and experimental values. Electrical discharge machined sample was characterized through scanning electron microscopy to study its surface after successive spark discharges.

Influence of B-field on the characteristics of pulsed spark discharges in water

Spark discharges in water have great potential for use in various technological fields, including pollutant degradation, precision micromachining, and nanomaterial production. However, the large-scale application of these discharges is limited by the complexity of the implicated physical and chemical phenomena, which cannot be easily controlled. In this study, we assess the effect of an external B-field on the electrical characteristics of multiple successive discharges, as well as on the erosion of the electrode. In addition to the B = 0 condition, two configurations of the B-field are investigated: B-parallel and B-perpendicular to the electrode axis, both at the magnitude of 125 mT. The obtained results demonstrate that discharge electrical characteristics and electrode erosion are significantly affected by the B-field. Using a W electrode, the highest and lowest discharge currents are measured in the case of B-perpendicular and B = 0, respectively. Meanwhile, the highest erosion volume is obtained in the case of B = 0. To assess the influence of electrode nature and magnetic properties on the discharges, the results obtained using W (paramagnetic) electrodes were compared to those obtained with Ni (ferromagnetic). The comparison shows that the discharge electrical data are tightly distributed when the Ni electrode is utilized, regardless of the B-condition, whereas the data obtained with the W electrode exhibit significant statistical variations in the presence of the B-field. Overall, the data reported herein indicate that the electrical properties of a spark discharge may be varied and controlled by applying an external B-field.

Placed Riprap Deformation Related to Axial Load at Toe Support: Physical Modelling

Rockfill dams are hydraulic structures of major importance. They can be exposed to extreme flood events, in turn leading to overtopping. These phenomena erode and affect structural and geotechnical integrity, which in turn can cause dam breach. Ripraps are broadly used for rockfill dam protection against such erosion processes. For steep slopes, as the one considered in this study (S = 1:1.5, vertical: horizontal), understanding the riprap behavior during overtopping is an important issue to improve dam design and reinforcement techniques. In this work, datasets are obtained from five experimental models of placed riprap built on a rock filter layer in a flume, at the hydraulic laboratory of the Norwegian University of Science and Technology, Trondheim. The riprap stones were placed in an interlocking pattern with a metallic support at the toe. The models were subjected to successive and incremental overtopping discharges until their complete failure. A laser traverse system was used to measure the coordinates (3D) of individual marked riprap stones between each discharge increase. Six load cells located at the toe measured the imposed loads during the entire procedure. From the total load values, two different types of load contributions could be distinguished: the self-weight of the stones and the hydraulic load depending on the discharge level of the overflow. This article highlights the strong relation in each of the five tests between riprap stone displacements, axial reaction load values measured at the toe and overtopping discharges. Moreover, as demonstrated in previous works, a buckling deformation of the riprap layer was observed and described. The results demonstrate that as the hydraulic load induces 2D deformations of the riprap, a larger part of the riprap weight is supported at the toe. Thus, the measured axial load during overtopping arises both from the hydraulic load and from the load imparted due to the compaction of the riprap layer. This compaction effect induces an even greater load than the one imposed due to the hydraulic contribution. The results from this study are finally put into perspective with the Norwegian Water Resources and Energy Directorate recommendations for full scale dams and suggest the great resistance of supported riprap at the toe.

Investigation on surface integrity in novel micro-EDM with two-dimensional ultrasonic circular vibration (UCV) electrode

The failure of Ti-6Al-4V components caused by poor surface integrity is a challenging problem in micro-EDM field. This paper presents a novel micro-EDM method adopting two-dimensional ultrasonic circular vibration (UCV) electrode instead of traditional rotating electrode, aiming to enhance the Ti-6Al-4V surface integrity from the perspective of increasing relative velocity between electrode and workpiece. The driving device for UCV electrode is developed and its working principle is analyzed. Based on simulation as well as experimental works, the integrity of surface machined by UCV electrode and rotating electrode are comparatively investigated. Results show that the sliding phenomenon of heat source generated in single pulse discharge is enhanced, thus the temperature gradient on machined surface is decreased. Meanwhile, the discharge energy in successive discharges becomes more consistent, which is beneficial to reduce the size fluctuation of discharge craters. In addition, the UCV electrode is helpful to suppress the abnormal discharges under the condition of ultra-high pulse frequency, thus the occurrence of long arc can be effectively prevented. As a result, the surface integrity are significantly improved in terms of surface roughness, residual stress and debris adhesion when UCV electrode is used, the phenomena of concentrated discharges and local surface ablation have also been effectively avoided. This study is expected to provide a new thought to improve the micro-EDM performance by lowering the surface defects.

Modeling of material removal morphology and prediction of surface roughness based on WEDM successive discharges

In this paper, a successive discharge material removal model is proposed to predict the surface roughness of the EN-GJL-250 (gray cast iron) under different discharge parameters of wire-cut electrical discharge machining (WEDM). Firstly, the finite element method (FEM) was used to analogue simulate the distribution of material surface temperature and flow field in the WEDM single pulse discharge machining process. According to the principle of energy conservation, the surface morphology and characteristic parameter size of a single pulse crater under different discharge parameters are simulated. Secondly, the discharge position is determined by the minimum gap width between the initial surface of the workpiece and the electrode wire during the establishment of the material removal model. Simulation results show that the magnitude of the single pulse discharge energy has an important influence on the morphology and characteristic size of the crater. Due to the different discharge energy, the increasing trend of crater radius, depth, and flanging height is not synchronized, and the increase of crater radius is more obvious and rapid. Meanwhile, the final morphology of the WEDM machined surface is determined by the morphology size of a single pulse crater and the location distribution of discharge points. Finally, the same discharge parameters are used to verify the surface quality of machined materials. Experimental results show that the surface morphology of the WEDM workpiece is in good agreement with the material removal model and the average relative error of surface roughness between the simulation results and the experimental results is 8.26%.

Investigation on the kerf and surface formation in the magnetic field-assisted WEDM-LS based on successive discharges

Magnetic field-assisted low-speed wire electrical discharge machining (MF-assisted WEDM-LS) is an effective technique to improve the surface quality of the workpiece. This paper presents a successive removing model to predict kerf width and the surface topography of nickel–titanium (Nitinol) shape memory alloy in different parameters. Firstly, the motion of an electron was calculated in the magnetic field. It could be obtained that if the length of the discharge channel path was the same with the condition that in traditional WEDM-LS, the width of the discharge gap was decreased because of the deflection of the electron trajectory caused by the magnetic field. Then, a modified gauss heat source equation was derived by calculating the incident angle of the discharge channel. Based on the principle of conservation of energy, the shape of the crater in different parameters was emulated. Moreover, an electrothermal coupling model was established to investigate the surface formation in the successive discharges process. The simulation results show that the average value of the surface roughness of the workpiece in WEDM-LS with magnetic field assisted was decreased by 12.3% compared with that in traditional WEDM-LS. Eventually, experiments of kerf and surface quality were carried out respectively. The experimental results showed that the kerf decreased from 376.2 to 361.7 μm in the magnetic field intensity of 0.4 T. The surface topographies of the workpieces showed good agreement with the simulation results, and the average relative error of surface roughness between simulated results and experimental results is 8.7%.

Study on Structural Parameters and Analysis Method of Soil Successive Impulse Discharge Channel

The transient analysis model of grounding systems is an important tool to analyze the lightning characteristics of grounding devices. When lightning enters the soil through the grounding device, there is a centralized discharge channel. The spatial structure of the discharge channel in the soil has a great effect on the accuracy of the transient analysis model of the soil impulse discharge. In this paper, based on the gray information analysis method, the volume of successive impulse discharge channels in the ground under various currents and soil conditions is calculated, and the changing law with time interval is analyzed. According to the experimental results, an analysis method of the model considering the discharge channel structure is proposed, and an example is analyzed. The results show that the time interval has an effect on the volume of the discharge channel. In a certain range, the volume of the channel increases with the time interval of successive impulse discharges. Taking the critical breakdown electric field strength as the judgment condition and the residual resistivity as the variable, the development process of the discharge channel can be simulated. The calculated results of the model are close to the experimental results.

Influence of Coniferous Wood Conditioning by Pulsed Electric Field on Its Combustion Heat Characteristics

The article presents the impact of sawdust conditioning from coniferous trees with a pulsed electric field (PEF) on the characteristics of the combustion heat. The study used four variants of electric field parameters, i.e., (I) 300 discharges with an electric field intensity of 25 kV·cm−1, (II) 150 discharges with an electric field intensity of 25 kV·cm−1, (III) 300 discharges with an electric field intensity of 30 kV·cm−1, (IV) 150 discharges with an electric field intensity of 30 kV·cm−1. It should be noted that the interval between successive discharges was 10 sec and it was constant for each variant of the experiment. A change in the characteristics of the heat of combustion was found under the influence of a pulsed electric field on sawdust from coniferous trees in each period of the measurement. The highest temperatures were achieved by the interaction of a pulsed electric field with a discharge pulse of 30 kV·cm−1 and the number of discharge cycles amounting to 300, whereas significantly lower temperature values were recorded with the discharge electric field intensity of 25 kV·cm−1. It was found that the longest times from the moment of ignition to reaching the maximum temperature were obtained for the material after the influence of PEF with an electric field intensity of 30 kV·cm−1 and the number of pulses 300 (IV combination), while the shortest time of the analyzed interval was stated for the first combination of the experiment (electric field intensity 25 kV·cm−1 and a number of pulses 150). The use of a pulsed electric field allows modeling the combustion time of a homogeneous material, which enables the improvement of the process control possibilities, and is also important information for the design of devices intended for biomass combustion.

A fossorial petalurid trace fossil from the Albian of Patagonia

Maichnus wetkaroae igen. isp. nov., from the Albian of Patagonia, is composed of two or three ellipsoidal oblate chambers connected to shafts that show swellings and concentrically laminated linings. Such laminated linings are also present in chambers, and probably originated by radial backfilling and/or the successive discharges of liquid organic excretions. This unique morphology occurs in paleosols showing evidence of waterlogging. Trace fossil morphology and the occurrence of traces in clusters in waterlogged soils indicate that M. wetkaroae igen. isp. nov. represents larval burrows of fossorial petalurids. This is the first record of Odonatan trace fossils from paleosols and also the oldest one. M. wetkaroae igen. isp. nov. is one of the oldest insect trace fossils recorded from paleosols. It represents the first and unique paleontological evidence of the ancient origin of the burrowing behavior of petalurids postulated only theoretically until now in evolutionary scenarios of Odonata.

Study on workpiece surface forming mechanism by successive discharges during USV-MF complex–assisted WEDM-LS process

Ultrasonic vibration and magnetic field complex–assisted techniques have been used in low-speed wire electrical discharge machining (USV-MF complex–assisted WEDM-LS) to improve workpiece surface quality. In this paper, a novel approach, which is based on a three-dimensional successive discharge model, is proposed to investigate the interaction between the workpiece surface forming and the vibration of a wire electrode. The influence of USV-MF complex–assisted technique on workpiece surface forming and vibration of a wire electrode is considered by modifying the parameters in this model. During the simulation, the discharge location, which is determined by the minimum gap width in each step, makes it possible to calculate the vibration of a wire electrode in the successive discharge process. Workpiece surface topographies are obtained at the end of simulation, as well as the vibration responses of the wire electrode and the distribution of discharge locations. The simulation results show that the USV-MF complex–assisted technique can increase the vibration amplitude of the wire electrode by 1.12%. The surface roughness values decrease more than 10% and the distribution uniformity of discharge location increases in the USV-MF complex assisted WEDM-LS process. The simulation results are verified by experiments and simulation error of surface roughness value is less than 5% compared with the experimental results. The analysis shows that the servo feed speed increases more than 50% with surface quality unaltered in the USV-MF complex–assisted WEDM-LS process.

EdgeCFD: a parallel residual-based variational multiscale code for multiphysics

High fidelity multiphysics simulations are ubiquitous in science and engineering but still face many challenges to run efficiently in today's supercomputers. This work reports advanced technologies present in EdgeCFD, a hybrid parallel variational multiscale multiphysics finite element software capable of running industrial problems involving turbulent incompressible, compressible, free-surface flows, advection-diffusion of multiple scalar fields, fluid-object interaction using an Arbitrary Lagrangian-Eulerian formulation, and, more recently, used to supporting uncertainty quantification. We also show the strategies to support the solution of large scale problems, including in-situ visualisation and how EdgeCFD handles computational steering. Industrial applications in the oil and gas industry are shown to demonstrate EdgeCFD capabilities. We present the analysis of vortex-induced vibration in cylindrical risers with appendages to reduce drag and lift, and the simulation of successive discharges of turbidity currents, a critical process for understanding the formation of oil reservoirs.

The role of associative ionization reactions in the memory effect of atmospheric pressure Townsend discharges in N2 with a small O2 addition

In this work, we investigate the role played by associative ionization reactions in the memory effect of atmospheric pressure Townsend dielectric barrier discharges working in N2 with a small addition of O2. Systematic laser-induced fluorescence measurements are carried out in order to provide the absolute densities of N and O atoms and NO molecules for different oxygen concentrations. The use of these data in a dedicated model allows us, in particular, to estimate the rate of the reaction suspected of playing a significant role. According to the obtained results, this reaction is found responsible for a significant enhancement in the production of seed electrons between two successive discharges at 25 ppm of O2, in good agreement with experimental observations. It confirms the importance of this associative ionization reaction in these experimental conditions.

Use of high-water marks and effective discharge calculation to optimize the height of bank revetments in an incised river channel

In deeply incised rivers, bankfull discharge (i.e. the flow filling the channel to the top of the banks) does not represent channel forming flow and increasingly large flows are associated with increasingly large boundary shear stress. In such rivers, solid bank revetments (rip-rap, gabions, retaining wall) are usually constructed to the top of the banks—similarly as in vertically stable rivers—despite the fact that the upper parts of the banks may never be flooded. To optimize the height of solid bank revetments in deeply incised channels, it is thus important to determine whether a flood magnitude can be identified, for which the combination of flow duration and bedload transport rate results in the highest river efficiency to transport bedload and perform geomorphic work. This question was explored in the Morávka River, Czech Carpathians, which deeply incised into non-resistant flysch bedrock over the past few decades. Observations of high-water marks (e.g. trash lines, wash lines) after a flood in 2014 enabled reconstruction of the peak flood stage in the deeply incised reach and the adjacent, vertically stable reach. These observations, together with post-flood measurements of cross-sectional channel geometry, distances between consecutive cross sections and estimates of channel roughness, were used in one-dimensional hydraulic modelling aimed to determine a peak discharge of the flood in a number of cross sections in both reaches. Despite the close proximity of both reaches, markedly higher discharge values were obtained for the incised reach and the discrepancy was used to calibrate roughness coefficients for the incised reach. A flow-duration curve determined on the basis of a 25-year series of daily discharges in the upstream gauging station together with data about channel geometry and roughness in the incised cross sections were used to simulate bedload transport at successive discharges with the BAGS sediment transport model. The calculations indicated the effective discharge for bedload transport in the incised reach to have the recurrence interval of 7–12 years. The upper limit of the reach-average effective discharge is associated with the stage slightly higher than a half of the bankfull depth. This highlights the disparity between effective and bankfull discharges and indicates that in incised channels, channel forming flow should be linked with the former. The vertical extent of the reach-average effective discharge is proposed as an indicator of the optimal, cost-effective height of solid bank-protection structures in the deeply incised channel and the suitability of this approach is discussed.

Effect of vibrationally excited N2(v) on atomic nitrogen generation using two consecutive pulse corona discharges under atmospheric pressure N2

Herein, we report on experimental results showing that vibrationally excited N2(v) plays an important role in producing nitrogen atoms in successive two-pulsed corona discharges. To investigate the effect of vibrationally excited N2(v) on the generation of atomic nitrogen, two pulses were generated such that their pulse intervals could be varied in a controlled manner. The resulting nitrogen atoms were measured using TALIF under atmospheric pressure N2 at different time points after each pulse. Firstly, the effect of pulse-to-pulse intervals (Δt) on the streamer formation of the second pulse discharge was observed. The results suggest that a decrease of Δt cause a reduction in the consumption of energy and inhibit streamer formation and propagation of a second pulse discharge. The energy efficiency of atomic nitrogen generation in the second pulse discharge near the anode tip was a maximum of approximately three times that of the first pulse. This efficiency decreases with increasing Δt and eventually became approximately equivalent to the value of the first pulse within Δt = 300 µs. This behavior is correlated with the temporal profile of the vibrational temperature after pulse discharge, which indicates that vibrationally excited N2(v) generated by the first pulse discharge plays a significant role in atomic nitrogen generation in the second pulse. The local densities of atomic nitrogen in the streamer channel for the first and second pulse discharges were estimated from their decay rate. The results suggest that the second pulse discharge generates atomic nitrogen while maintaining the local density of the first discharge pulse in the streamer channel, irrespective of Δt. Moreover, it indicates that the main generation region of atomic nitrogen in the second pulse discharge is different from that of the first pulse, although the second pulse discharge uses vibrationally excited N2(v) to generate atomic nitrogen.

Characterization of Various Air Plasma Discharge Modes in Contact with Water and Their Effect on the Degradation of Reactive Dyes

Plasma in- or in-contact-with liquid is an emerging technology that has high potential for use in liquid treatment applications. Due to the simultaneous production of highly reactive species, plasmas can efficiently eliminate pollutants that are difficult to remove using conventional methods. In this study, we investigate an AC-driven air plasma in contact with water, generated using five discharge modes. Modes 1, 2, and 3 are run at air-gap distance of 1, 3, and 3.5 mm, respectively, at a repetition rate of 10 kHz (sinusoidal waveform). Water polarity alternates between cathode and anode in modes 1 and 2, whereas mode 3 produces anode polarity only. Mode 4 is similar to mode 1, but with a repetition rate of 5 kHz, while mode 5 is similar to mode 3, but without the high-voltage preceding discharge when water is anode. The electrical characteristics of each discharge mode are presented in detail, and variations in water properties (namely water acidity and conductivity) are also discussed. The effect of discharge mode on the degradation rate of methylene blue (MB), a standard pollutant, is also investigated. Modes 1, 2, and 4 exhibit comparable MB degradation efficiencies, indicating insignificant dependence neither on air-gap distance or number of discharges. The difference between the efficiencies obtained using modes 3 and 5 suggests a substantial effect of the electric field applied between two successive discharges.

Water retention and drainage capability of expanded cork agglomerate boards intended for application in green vertical systems

The expansion of urban centres, together with the increasing frequency of extreme weather phenomena, have prompted the need to study and implement Natural-Based Solutions that can enhance the sustainability and resilience of cities. In this context, green vertical systems (GVS) have been referred to as eco-efficient solutions with potential benefits in terms of building insulation and urban environment. Nonetheless, the sustainability of these solutions has been questioned due to the possible low environmental performance of some of the materials used and the irrigation needed to support vegetation.This work describes studies that have been performed to evaluate expanded cork agglomerate as an alternative eco-friendly material for building GVS. Expanded cork agglomerate is an insulation material produced with by-products from the industry, which may have benefits when used in GVS in terms of regulating the moisture in the planted facade. Experimental tests were carried out to evaluate the water retention and drainage capability of expanded cork agglomerate boards of varying density, height and thickness.For this, board specimens were fully laterally confined in a watertight box with open ends at the top and bottom, with successive water discharges being carried out on the top. Other tests were performed with the front of the box removed, thus allowing the water to drain from the facade too. The results suggest that expanded cork agglomerate is suitable for use in GVS, with the boards achieving water retention up to 20 kg/m3 and providing rapid drainage of excess of water.