Instantaneous Drop Research Articles

순시전압강하 보상 기능을 가지는 무정전전원공급장치의 개발

In this paper, UPS, with a built-in instantaneous sag drop compensation features, was developed to improve performance. The improved UPS, using instantaneous moving average method, compensates by quickly measuring the voltage and series inverter of half-bridge type, using line-interactive method that links with the voltage of the battery and power source, was developed. In addition, by developing a parallel inverter that uses a high-efficiency PWM switching method, overall UPS system was enhanced. To verify the performance of the proposed algorithm, single-phase 5[kVA] UPS systems were designed and the experimental system was constructed. The low-cost type of Cortex-M3 module CPU STM32F103R8T6 (32[bit]) is attached and the switching time of mode transfer was set within 4 [ms]. THD of the linear load operates in less than 3[%], and the stability of the output voltage operates in approximately ±2[%] range. The superior performance of the operations was confirmed with the system set as above.

Multiple knickpoints in an alluvial river generated by a single instantaneous drop in base level: experimental investigation

Abstract. Knickpoints often form in bedrock rivers in response to base-level lowering. These knickpoints can migrate upstream without dissipating. In the case of alluvial rivers, an impulsive lowering of base level due to, for example, a fault associated with an earthquake or dam removal commonly produces smooth, upstream-progressing degradation; the knickpoint associated with suddenly lowered base level quickly dissipates. Here, however, we use experiments to demonstrate that under conditions of Froude-supercritical flow over an alluvial bed, an instantaneous drop in base level can lead to the formation of upstream-migrating knickpoints that do not dissipate. The base-level fall can generate a single knickpoint, or multiple knickpoints. Multiple knickpoints take the form of cyclic steps, that is, trains of upstream-migrating bedforms, each bounded by a hydraulic jump upstream and downstream. In our experiments, trains of knickpoints were transient, eventually migrating out of the alluvial reach as the bed evolved to a new equilibrium state regulated with lowered base level. Thus the allogenic perturbation of base-level fall can trigger the autogenic generation of multiple knickpoints which are sustained until the alluvial reach recovers a graded state.

Detecting Subtle Plasma Membrane Perturbation in Living Cells Using Second Harmonic Generation Imaging

The requirement of center asymmetry for the creation of second harmonic generation (SHG) signals makes it an attractive technique for visualizing changes in interfacial layers such as the plasma membrane of biological cells. In this article, we explore the use of lipophilic SHG probes to detect minute perturbations in the plasma membrane. Three candidate probes, Di-4-ANEPPDHQ (Di-4), FM4-64, and all-trans-retinol, were evaluated for SHG effectiveness in Jurkat cells. Di-4 proved superior with both strong SHG signal and limited bleaching artifacts. To test whether rapid changes in membrane symmetry could be detected using SHG, we exposed cells to nanosecond-pulsed electric fields, which are believed to cause formation of nanopores in the plasma membrane. Upon nanosecond-pulsed electric fields exposure, we observed an instantaneous drop of ∼50% in SHG signal from the anodic pole of the cell. When compared to the simultaneously acquired fluorescence signals, it appears that the signal change was not due to the probe diffusing out of the membrane or changes in membrane potential or fluidity. We hypothesize that this loss in SHG signal is due to disruption in the interfacial nature of the membrane. The results show that SHG imaging has great potential as a tool for measuring rapid and subtle plasma membrane disturbance in living cells.

Green extraction processes of natural products as tools for biorefinery

AbstractThis review introduces a new and innovative area in the frontiers of chemistry, biology and processing: green extraction with special emphasis on natural products processing. Green extraction is a part of the sustainable development and industrial strategy; its history, concept, principles, and fundamentals are described. We pay special attention to the strategies and the tools available to make biorefinery greener. This review presents the innovative research in this area in the past five years in terms of innovative techniques (microwave, ultrasound, instantaneous pressure drop, supercritical fluid extraction, pressing) applied to green extraction of natural products with special examples applied to biorefinery concept.

Seeding optimization for instantaneous volumetric velocimetry. Application to a jet in crossflow

Every volumetric velocimetry measurements based on tracer (particles, bubbles, etc.) detection can be strongly influenced by the optical screening phenomenon. It has to be taken into account when the statistical properties associated to the performances of the particle detection and tracking algorithms are significantly affected. It leads to a maximum concentration of particles in the images thus limiting the final spatial resolution of the instantaneous three-dimensional three-components (3D3C) velocity fields. A volumetric velocimetry system based on Defocused Digital Particle Image Velocimetry (DDPIV), named Volumetric 3-Components Velocimetry (V3V), is used to show that above a critical visual concentration of particles in the images, the concentration and accuracy of the final instantaneous raw velocity vector field drop. The critical concentration depends on physical parameters as well as on the processing algorithms. Three distinct regimes are identified. In the first regime, the concentration is well adapted to volumetric velocimetry, the largest concentration being optimal to maximize the number of valid velocity vectors. In the second regime, the performances of the detection and tracking algorithms are no longer optimal. Finally, the third regime is strongly influenced by optical screening. A rigorous methodology is proposed to optimize volumetric measurements taking into account the system specifications (pixel size, focal length, system magnification, etc.). An optimal particle concentration of 4.5×10−2particlespixel−1 (ppp) is found. A relationship between the imaged concentration and the optimal final spatial resolution for fully interpolated instantaneous velocity field is obtained. The present study can be used as a guideline to achieve the measurement of instantaneous three-dimensional velocity fields with a good spatial resolution. It is finally successfully applied to a complex 3D flow test case: a jet in cross-flow.

On the contact region of a diffusion-limited evaporating drop: a local analysis

AbstractMotivated by experiments showing that a sessile drop of volatile perfectly wetting liquid initially advances over the substrate, but then reverses, we formulate the problem describing the contact region at reversal. Assuming a separation of scales, so that the radial extent of this region is small compared with the instantaneous radius$a$of the apparent contact line, we show that the time scale characterizing the contact region is small compared with that on which the bulk drop is evolving. As a result, the contact region is governed by a boundary-value problem, rather than an initial-value problem: the contact region has no memory, and all its properties are determined by conditions at the instant of reversal. We conclude that the apparent contact angle$\theta $is a function of the instantaneous drop radius$a$, as found in the experiments. We then non-dimensionalize the boundary-value problem, and find that its solution depends on one parameter$\mathscr{L}$, a dimensionless surface tension. According to this formulation, the apparent contact angle is well-defined: at the outer edge of the contact region, the film slope approaches a limit that is independent of the curvature of bulk drop. In this, it differs from the dynamic contact angle observed during spreading of non-volatile drops. Next, we analyse the boundary-value problem assuming$\mathscr{L}$to be small. Though, for arbitrary$\mathscr{L}$, determining$\theta $requires solving the steady diffusion equation for the vapour, there is, for small$\mathscr{L}$, a further separation of scales within the contact region. As a result,$\theta $is now determined by solving an ordinary differential equation. We predict that$\theta $varies as${a}^{- 1/ 6} $, as found experimentally for small drops ($a\lt 1~\mathrm{mm} $). For these drops, predicted and measured angles agree to within 10–30 %. Because the discrepancy increases with$a$, but$\mathscr{L}$is a decreasing function of$a$, we infer that some process occurring outside the contact region is required to explain the observed behaviour of larger drops having$a\gt 1~\mathrm{mm} $.

Black holes in short period X-ray binaries and the transition to radiatively inefficient accretion

By comparing the orbital period distributions of black hole and neutron star low mass X-ray binaries (LMXBs) in the Ritter-Kolb catalogue we show that there is statistical evidence for a dearth of black hole systems at short orbital periods (P_orb < 4h). This could either be due to a true divergence in orbital period distributions of these two types of system, or to black hole LMXBs being preferentially hidden from view at short orbital periods. We explore the latter possibility, by investigating whether black hole LMXBs could be concealed by a switch to radiatively inefficient accretion at low luminosities. The peak luminosity and the duration of X-ray binary outbursts are related to the disc radius and, hence, the orbital period. At short periods, where the peak outburst luminosity drops close to the threshold for radiatively inefficient accretion, black hole LMXBs have lower outburst luminosities, shorter outburst durations and lower X-ray duty cycles than comparable neutron star systems. These factors can combine to severely reduce the detection probability of short period black hole LMXBs relative to those containing neutron stars. We estimate the outburst properties and orbital period distribution of black hole LMXBs using two models of the transition to radiatively inefficient accretion: an instantaneous drop in accretion efficiency (eta) to zero, at a fraction (f) of the Eddington luminosity (L_Edd) and a power-law efficiency decrease, eta \propto \dot{M}^n, for L < f*L_Edd. We show that a population of black hole LMXBs at short orbital periods can only be hidden by a sharp drop in efficiency, either instantaneous or for n >= 3. This could be achieved by a genuine drop in luminosity or through abrupt spectral changes that shift the accretion power out of a given X-ray band.

Effect of induced airflow on the surface static pressure of pleated fabric filter cartridges during pulse jet cleaning

Filter cartridges with higher pleat ratios and larger filter surfaces are often cleaned incompletely because of the great variation in the static pressure distribution along the surface of filter cartridges during the pulse jet cleaning process. This study examined the static pressure distribution of filter cartridges and attempted to reduce the incidence of incomplete cleaning, particularly at the top of a filter cartridge, where less static pressure could cause systematic unstable operations. Pressure loss and static pressure behavior were observed across pleated filter cartridges in a dust collector during the pulse jet cleaning process. The instantaneous pressure drops of pleated filters were measured, and filter aging over time was recorded. The pressure drops of pleated filters with induced airflows are less significant than those without induced airflows. The static pressure and the continuous pressure time on the filter cartridges surfaces were obtained using a pressure transducer. The induced airflow was used to alter the static pressure distribution along the filter cartridge surface. The air axial velocity gradually decreased from the supersonic induced nozzle and through the air diffuser. Otherwise, radial velocity increased before encountering the filter cartridge surface, and the dynamic pressure was quickly converted into static pressure at the top of the filter cartridge before being transported to the middle of the filter cartridge and then immediately to the bottom. Sometimes, partial airflow moved into the filter cartridges and rebounded from the bottom of the filter cartridges, thereby forming partial static pressure at the bottom. Thus, the static pressure decreased from the top of the filter cartridge to the bottom. The experimental results show that the static pressure at the top area of the filter cartridges is 23–17kPa and the static pressure at the bottom area of the filter cartridges is 4.7–1.6kPa via the operational time with the 0.6MPa tank pressure in our experiment. The measured results are in good agreement with our photos. This variation resolved the cleaning difficulty at the top of the filter cartridge and maintained the entire systematic sustainable operation.

Role of Nanoparticles and Relaxation on Strain-Induced Crystallization Behavior in Uniaxially Stretched Polyethylene Naphthalate Films: A Mechano-Optical Study

The effects of nanoparticle concentration and processing conditions on the relaxation behavior of PEN nanocomposites are investigated using mechano optical techniques where birefringence, true stress and true strain are measured while subjecting the polymer films to uniaxial deformation followed by relaxation. For this purpose, two different stretching temperatures were employed to stretch the films containing 0.5 and 2 wt % nanoparticles: one above and the other below the Tll (liquid–liquid transition). Increasing the temperature as well as the addition of nanoparticles suppresses the spontaneous deformation processes leading to sharp increase in true strain. An instantaneous stress drop is observed during relaxation below the Tll corresponding to the initial glassy component observed in the stress-optical behavior during stretching. This stress is attributed to the presence of segmental rigid correlations that were not broken during the stretching stage. This behavior was found to be absent above the li...

3-D microscale simulation of dust-loading in thin flat-sheet filters: A comparison with 1-D macroscale simulations

In this work, a microscale approach is undertaken to simulate the instantaneous pressure drop and collection efficiency of fibrous media exposed to particle loading, i.e., filter aging. The air flow field through 3-D disordered geometries representing the internal microstructure of a fibrous filter is obtained by numerically solving Stokes' equations. A Lagrangian approach is used to track the trajectory of particles through our virtual filter media and determine the filter's collection efficiency under different dust-load conditions. The calculations were conducted using the ANSYS CFD code enhanced with a series of in-house C++ subroutines. To better illustrate the value of such CPU-intensive 3-D microscale modeling, we compared the results of our simulations with those obtained from a 1-D macroscale model developed based on some of the pioneering studies reported in the literature. It was found that while the 1-D macroscale models can provide fast predictions for the pressure drop and collection efficiency of a given filter, they require a series of empirical correction factors or case-specific assumptions that limit their usage for design and development of new filter media. The 3-D microscale simulation methods, in contrast, are self-sufficient as they are developed based on first principles. With the current rate of progress in developing high-speed computers, it is expected that 3-D microscale simulations will be the preferred method of filter design in the near future.

아크사고 발생 시 전압 왜형파를 이용한 아크차단기 개발

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The principal factor of the fire is electric arc or spark accompanied with such electric faults. Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB), that is, Residual Current Protective Devices (RCDs) used on low voltage distribution lines cut off earth leakage and overload, but the RCD can not cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied in low voltage distribution panel are prescribed to rated breaking time about 30[ms] (KS C 4613), the RCDs can"t perceive to the periodic electric arc or spark of more short wavelength level. To improve such problems, this paper studies on an arc fault circuit interrupter (AFCI) using the distorted voltage wave in electric arc faults. The proposed voltage sensing type AFCI is an electrical fire prevention apparatus of new conception that operates a circuit breaker with sensing the instantaneous voltage drop of line voltage at electrical faults occurrence. The proposed AFCI is composed of control circuit topology using some semiconductor switching devices. Some experimental tests of the proposed AFCI confirm practicality and the validity of the analytical results.

Timescales of seawater intrusion and retreat

Quantifying the timescales associated with moving freshwater–seawater interfaces is critical for effective management of coastal groundwater resources. In this study, timescales of interface movement in response to both inland and coastal water level variations are investigated. We first assume that seawater intrusion (SWI) and retreat (SWR) are driven by an instantaneous freshwater-level variation at the inland boundary. Numerical modelling results reveal that logarithmic timescales of SWI (lnTi) and SWR (lnTr) can be described respectively by various simple linear equations. For example, SWI timescales are described by lnTi=a+blnh′f–s, where a and b are linear regression coefficients and h′f–s is the boundary head difference after an instantaneous drop of inland freshwater head. For SWR cases with the same initial conditions, but with different increases in freshwater head, lnTr=c+dΔXT, where c and d are regression coefficients and ΔXT is the distance of toe response that can be estimated by a steady-state, sharp-interface analytical solution. For SWR cases with the same freshwater head increase, but with different initial conditions, in contrast, lnTr=e+flnΔXT, where e and f are regression coefficients. The timescale of toe response caused by an instantaneous variation of sea level is almost equivalent to that induced by an instantaneous inland head variation with the same magnitude of water level change, but opposite in direction. Accordingly, the empirical equations of this study are also applicable for sea-level variations in head-controlled systems or for simultaneous variations of both inland and coastal water levels. Despite the idealised conceptual models adopted in this study, the results imply that for a particular coastal aquifer, SWI timescales are controlled by the boundary water levels after variations, whereas SWR timescales are dominated by the distance of toe response.

DropBot: An open-source digital microfluidic control system with precise control of electrostatic driving force and instantaneous drop velocity measurement

We introduce DropBot: an open-source instrument for digital microfluidics (http://microfluidics.utoronto.ca/dropbot). DropBot features two key functionalities for digital microfluidics: (1) real-time monitoring of instantaneous drop velocity (which we propose is a proxy for resistive forces), and (2) application of constant electrostatic driving forces through compensation for amplifier-loading and device capacitance. We anticipate that this system will enhance insight into failure modes and lead to new strategies for improved device reliability, and will be useful for the growing number of users who are adopting digital microfluidics for automated, miniaturized laboratory operation.

Estimation of Battery State of Health Using Probabilistic Neural Network

In this study, a probabilistic neural network (PNN) is used to estimate the state of health (SOH) of Li-ion batteries. The accurate prediction of SOH can help avoid inconveniences or fatal accidents from the sudden malfunction of the battery. A total of 110 pieces of Li-Co batteries are used. Constant current/voltage recharging and constant current discharging are performed for the life-cycle test of the battery. The data obtained from the recharging and discharging electric characteristics as well as the life-cycle test of the battery are used to estimate the SOH of the battery. The test data show that the constant current charging time, the instantaneous voltage drop at the start of discharging, and the open circuit voltage are the most important characteristics for estimating the SOH of the battery. The PNN is trained using 100 pieces of batteries. The remaining 10 pieces are used to verify the feasibility of the proposed method. The effectiveness of the PNN training using a number of samples is discussed and analyzed. The results show that the average error of the prediction is 0.28% and the standard deviation is 1.15%. The computation time of the PNN is 62.5 ms. Thus, the proposed method can accurately estimate the SOH of the battery in a short period.

사고전압 감지형 아크차단 제어회로 개발

본 논문은 사고전압 감지형의 아크차단 제어회로에 대한 연구로써, 전기사고 발생 시 선간전압의 순간적인 전압감쇠를 감지하여 기존 차단기를 동작시키는 전압감지형 전기화재 예방장치이다. 현재 저압배전 계통에 사용중인 누전차단기, 배선용차단기 그리고 RCD 등은 전기화재의 주요 요인인 아크사고에 대해 보호능력이 없는 것으로 분석된다. 본 논문에서는 이러한 문제점들을 개선하기위하여 이전의 전류감지에 의한 아크사고 차단방식이 아닌 사고발생 시 전압파형의 왜곡을 이용한 새로운 전압감지형 아크차단 제어회로를 개발하여 전기화재를 예방하고자 한다. 제안한 아크차단 제어회로는 소형 경량으로 제작되는 장점과 다양한 동작분석을 통하여 그 실용성을 검증하였다. This paper studies on an arc fault interruption control circuit (AFICC) of fault voltage sensing type. The proposed voltage sensing type AFICC (VST_AFICC) is an electrical fire prevention apparatus that operates the existing circuit breaker with sensing the instantaneous voltage drop of line voltage when occurs electrical faults. The existing Earth Leakage Circuit Breaker (ELB), Molded_case Circuit Breaker (MCCB), and Residual Current Protective Devices (RCDs) used in low voltage distributing system don't have protective capability from electric arc faults to be a major factor of electrical fire. In this paper to improve such problems, a new VST_AFICC using the distortion of voltage waveform when occurs electrical faults is proposed to prevent electrical fire. There is characteristic that the control method of proposed apparatus is different from previous current sensing type. The proposed AFICC has merit that is manufactured by small size and light weight. The practicality of a new VST_AFICC is also verified through various operation analysis.

Statistical optimization of operating conditions for supercritical carbon dioxide-based pretreatment of guayule bagasse

A central composite design (CCD) was used to find the optimal temperature, pressure, moisture and duration for the supercritical CO2-based pretreatment of guayule, a desert shrub for commercial production of hypoallergenic latex. The pretreatment involved: adding water to the biomass, raising system temperature, pressurizing with supercritical CO2, holding the system for a period of time, and exploding the biomass by rapidly opening the vent valve. The pretreated biomass was then hydrolyzed at 30 °C for 72 h in an enzyme solution with 5% (w/v) solid loading. The yields of released glucose and pentose were determined and used as the CCD response variables. Statistical analysis of results led to the following recommended condition: 175 °C, 26.2 MPa (3800 psi), 60% moisture and 30 min. The corresponding glucose and pentose yields were 56% and 61%. X-ray diffraction analysis was done to get the crystallinity index of the bagasse before and after pretreatment. Scanning electron microscopy was also used to examine the structural changes caused by pretreatment. These characterizations indicated that at milder conditions, the pretreatment exposed cellulose and hemicellulose for subsequent enzyme attack; at harsher conditions, the pretreatment destroyed cellulose crystallinity and gave higher glucose yields. To isolate the explosion effect (caused by instantaneous pressure drop, ΔP) from the reaction (pressure) effect, a series of experiments was made with the bagasse pretreated at the same condition (27.6 MPa) but exploded against different back pressures. The explosion needed to be severe enough (with ΔP > 17 MPa) to give a sugar yield of over 50%.

Dynamic high pressure microfluidization-assisted extraction and antioxidant activities of sweet potato (Ipomoea batatas L.) leaves flavonoid

Dynamic high pressure microfluidization (DHPM) is an emerging technology utilizing the collective forces of high-velocity impact, high-frequency vibration, instantaneous pressure drop, intense shear, cavitation, and ultra-high pressures. DHPM technology was applied to improve the extraction of flavonoids from sweet potato leaves, and its effect was evaluated using six samples under various conditions. Pretreatment with DHPM was found to strengthen the antioxidant activities of the flavonoid, while no treatment or post-treatment with DHPM, produced weaker antioxidant activities. This suggests that the DHPM technology may provide a promising method of utilizing sweet potato leaves as a natural antioxidant in food and pharmaceutical industry.

A macroscale model for simulating pressure drop and collection efficiency of pleated filters over time

In this work, a computationally affordable macroscale model is developed to simulate the instantaneous collection efficiency and pressure drop of pleated depth filters. The numerical scheme presented here allows for the deposition of particles inside the fibrous fabric of a pleated filter, and accordingly varies its permeability and capture efficiency to simulate aging of the filter over time. This has been accomplished by developing a series of in-house subroutines that remarkably enhance the capabilities of the commercially available computational fluid dynamics code from ANSYS. This model is used to quantify the influence of pleat count, particle diameter, and flow velocity on the instantaneous performance of pleated filters with V-shaped pleats. Our results indicate that increasing the number of pleats reduces the rate of increase of a filter’s pressure drop and capture efficiency. Predictions of our model have been compared against available experimental data, and good agreement has been observed.

Impact of the European Russia drought in 2010 on the Caspian Sea level

Abstract. The hydrological budgets of the Volga basin (VB) and the Caspian Sea (CS) have been analysed. The components of the water balance for the CS were calculated for the period 1993 to 2010 with emphasis on summer 2010 when a severe drought developed over European Russia. A drop in precipitation over the VB in July 2010 occurs simultaneously with a decrease in evaporation for the same area, an increase of evaporation over the CS itself and a drop of the Caspian Sea level (CSL). The drop in the precipitation over the VB cannot lead to an instantaneous drop of the CSL because the precipitated water needs some months to reach the CS. The delay is estimated here to be 1 to 3 months for excessive precipitation in summer, longer for deficient precipitation and for winter cases. However, the evaporation over the CS itself is considered to be responsible for a simultaneous drop of the CSL from July to September 2010. The impact on the CSL from the precipitation deficit over the VB occurs in the months following the drought. The water deficit from July to September 2010 calculated from the anomalous precipitation minus evaporation over the VB would decrease the CSL by 22 cm, of which only 2 cm had been observed until the end of September (observed Volga River discharge anomaly). So the remaining drop of 20 cm can be expected in the months to follow if no other anomalies happen. In previous studies the precipitation over the VB has been identified as the main cause for CSL changes, but here from a 10 cm drop from beginning of July to end of September, 6 cm can be directly assigned to the enhanced evaporation over the CS itself and 2 cm due to reduced precipitation over the CS. Further periods with strong changes of the CSL are also investigated, which provide some estimates concerning the accuracy of the analysis data. The investigation was possible due to the new ECMWF interim reanalysis data which are used to provide data also for sensitive quantities like surface evaporation and precipitation. The comparison with independent data and the consistency between such data for calculating the water budget over the CS gives a high confidence in the quality of the data used. This investigation provides some scope for making forecasts of the CSL few months ahead to allow for mitigating societal impacts.

Characterization of a microfluidic in vitro model of the blood-brain barrier (μBBB)

The blood-brain barrier (BBB), a unique selective barrier for the central nervous system (CNS), hinders the passage of most compounds to the CNS, complicating drug development. Innovative in vitro models of the BBB can provide useful insights into its role in CNS disease progression and drug delivery. Static transwell models lack fluidic shear stress, while the conventional dynamic in vitro BBB lacks a thin dual cell layer interface. To address both limitations, we developed a microfluidic blood-brain barrier (μBBB) which closely mimics the in vivo BBB with a dynamic environment and a comparatively thin culture membrane (10 μm). To test validity of the fabricated BBB model, μBBBs were cultured with b.End3 endothelial cells, both with and without co-cultured C8-D1A astrocytes, and their key properties were tested with optical imaging, trans-endothelial electrical resistance (TEER), and permeability assays. The resultant imaging of ZO-1 revealed clearly expressed tight junctions in b.End3 cells, Live/Dead assays indicated high cell viability, and astrocytic morphology of C8-D1A cells were confirmed by ESEM and GFAP immunostains. By day 3 of endothelial culture, TEER levels typically exceeded 250 Ω cm(2) in μBBB co-cultures, and 25 Ω cm(2) for transwell co-cultures. Instantaneous transient drop in TEER in response to histamine exposure was observed in real-time, followed by recovery, implying stability of the fabricated μBBB model. Resultant permeability coefficients were comparable to previous BBB models, and were significantly increased at higher pH (>10). These results demonstrate that the developed μBBB system is a valid model for some studies of BBB function and drug delivery.