Wall Force Research Articles

Research on Coordinated Relationship Between Deformation and Force in Shaft Foundation Pit Support Structures

In order to investigate the coordinated relationship between lateral deformation of the diaphragm wall and axial force of the internal strut, this paper first carried out a scaled model test on the mechanical features of a foundation pit support system based on a novel axial force servo device. Then, a finite element model was established to simulate the scaled model test, and the correctness of the finite element modeling approach was validated by comparing test results. After that, the same finite element modeling method was used to analyze the coordinated relationship between axial force and lateral deformation in the prototype foundation pit support structure. The results show that the axial force of the inner strut is negatively correlated with the lateral deformation in the diaphragm wall. The initial maximum lateral deformation in the diaphragm wall of the shaft foundation pit occurs at the bottom of the foundation pit, so changing the length of bottom strut simultaneously is the most effective way to adjust the mechanical behavior of the support structure. Under various support conditions, the maximum lateral deformation of the diaphragm wall in the prototype project is 0.59~0.66‰ of the total excavation depth of the foundation pit, and the maximum axial force of internal support is 11~30% of the yield load of a single steel strut.

Coal‐wall spalling prevention mechanism using advance‐grooving pressure relief in the large‐mining‐height working face of a shallow coal seam

AbstractIn mining, the roof structure of a working face with a large mining height in a shallow‐buried coal seam is prone to cutting instability in front of the support, which causes support crushing and coal‐wall spalling. This study analyzes 2201 working faces with large mining heights in the Haiwan No. 3 Mine by investigating the mechanical response law of coal walls under the transient excitation of roof structure instability. A mechanical model of coal walls under dynamic and static load coupling is established, revealing the formation mechanism of coal wall spalling and its main influencing factors. Prevention and control technologies of advanced grooving and pressure relief are proposed, and grooving parameters are determined. The results show that: During the mining process of large mining height working face in shallow buried coal seam, the step change of static response of coal wall is induced by the transient instability of roof structure, and the high abutment pressure is formed on the coal wall. At the same time, the strain energy and gravitational potential energy of roof cutting instability are released to form a dynamic load. Under the action of dynamic and static load, the plastic failure dissipation power of the coal wall is greater than the critical power, and the coal wall spalling occurs. The main influencing factors are mining load, mining height, and internal friction angle of the coal wall. The method of advanced grooving pressure relief can change the roof structure and coal force mechanism, by cutting off the connection between the coal wall and immediate roof, reducing the height of the coal wall force, effectively controlling the position of the roof cut off break line, reducing the static load effect of the roof on the coal, and transferring the position of the dynamic load response to the depth of the coal wall. When the grooving height‐depth ratio k is 0.75, the peak value of the abutment pressure moves 5.57 m to the front of the working face, and the pressure relief effect is the best. The above research results provide an effective active protection method for controlling coal wall spalling in fully mechanised working face with large mining height.

Turbulent flow and wall forces in staggered square cylinder porous media: An LES Analysis

Abstract The Wall-Modeled-Large Eddy Simulation (WMLES) technique was used to analyze turbulent flow in a porous medium composed of a staggered arrangement of square cylinders. The study focused on a porosity range of 0.3 to 0.8 at a pore Reynolds number of 10×103. The research provides novel information on pressure and shear force distributions around the cylinders and time-averaged values of particle drag and fluctuating lift coefficients. Results indicate that the flow physics are mainly driven by an expansion region in front of the central particle and another in the rear, where the flow is contracted and strongly accelerated. In the first region, velocities, turbulence kinetic energy (k), and its dissipation rate (e) are attenuated by a sudden pressure increase, while in the contraction region, the effect is the opposite. As porosity decreases, flow gradients and the overall levels of k, e, and Reynolds stresses become more significant. Turbulent anisotropy increases as porosity decreases below 0.6. Hydrodynamic stresses in the last interval present relatively uniform levels, which is a unique feature that may be considered in designing dedicated engineering devices with controlled stresses.

Interaction of a self-expandable stent with the arterial wall in the presence of hypocellular and calcified plaques.

Self-expandable stents manufactured from nitinol alloys are commonly utilized alongside traditional balloon-expandable stents to provide scaffolding to stenosed arteries. However, a significant limitation hampering stent efficacy is restenosis, triggered by neointimal hyperplasia and resulting in the loss of gain in lumen size, post-intervention. In this study, a nonlinear finite element model was developed to simulate stent crimping and expansion and its interaction with the surrounding vessel in the presence of a plaque. The main aim was to determine contact pressures and forces induced at the interface between an artery wall with hypocellular and calcified plaques and an expanded stent. The results demonstrated the drawbacks of plaque calcification, which triggered a sharp contact pressure and radial force surge at the interface as well as a significant rise in von Mises stress within the vessel, potentially leading to rupture and restenosis. A regression line was then established to relate hypocellular and calcified plaques. The adjusted coefficient of determination indicated a good correlation between contact pressures for calcified and hypocellular plaque models. Regarding the directionality of wall properties, contact pressure and force observations were not significantly different between isotropic and anisotropic arteries. Moreover, variations in friction coefficients did not substantially affect the interfacial contact pressures.

Optimization of non-spherical particle flow in vertical waste heat recovery devices: Analyzing structural configurations

Vertical waste heat recovery devices are emerging but are immature. The vertical waste heat recovery devices of circular, square, and optimized designs were analyzed for a full capacity of 8 tons of sintered ore. Using DEM theory, the effects of particle size distribution, velocity, and wall forces on void fraction distribution and particle flow were examined. The circular device demonstrated superior mixed particle flow compared to the square device, achieving integrated flow for 50 % of particles in the cone, in contrast to 26 % for the square device. An optimized circular device achieved integral flow for 90 % of particles, significantly enhancing overall flow and reducing wall adhesion, attributed to its improved internal design. Through insert and distributor design, the overall particle flow within the device improved, with almost no particles remaining on the walls. These findings underscore the potential for enhanced heat recovery efficiency through optimized internal structures in waste heat recovery devices.

Splitting of double-core solid-in-water-in-oil droplet in a microfluidic Y-junction

Solid particle-encapsulated droplets have significant applications in biochemistry, advanced materials, and inertial confinement fusion (ICF) experiments. However, there is a problem of encapsulating two solid cores in a single droplet during the preparation of single-core droplets, which reduces the utilization efficiency. In this study, an effective microfluidic approach for continuous splitting of solid-in-water-in-oil droplets encapsulating double solid cores is developed. Visualization experiments are conducted to analyze the movements of solid cores and evolution of liquid–liquid interface during the splitting. The results show that the squeezing stage during the splitting process is shortened due to the presence of solid cores. The splitting mechanisms were also revealed by analyzing the interaction forces between the solid cores and aqueous phase. The force analysis of the aqueous phase showed that sum of squeezing and shear force could overcome the interfacial tension, ensuring the successful splitting of the double-core droplets. The force analysis of the solid cores revealed that the motion of the core could be divided into three typical stages: deceleration, hitting and separation. The combined effect of the aqueous phase, channel wall, and interfacial forces ensured the stable separation of the two solid cores. The length distribution of the daughter droplets exhibited excellent monodispersity. The microfluidic method proposed in this work would effectively improve the controlled preparation efficiency of solid-in-water-in-oil droplets.

Integrated Plug High-Strength Geocell Reinforcement in Foundation Design for Square Footing

This paper develops an analytical model to calculate the ultimate bearing capacity of the integrated plug high-strength geocell (IPGC)-reinforced foundation under a square footing. The high strength and stiffness of the geocell wall and the typical failure of the integrated plug-in joint tearing were considered. The ultimate bearing capacity of the IPGC-reinforced foundation was calculated in two separate parts. The ultimate bearing capacity of an unreinforced foundation was calculated using the modified Terzaghi equation. The increased bearing capacity of the IPGC was calculated as the function of the tearing force of the geocell wall, the height and the diameter of a geocell, the empirical static earth pressure coefficient, and the vertical additional stress coefficient under uniformly distributed rectangular loading. The results showed that the maximum error between the experimental and the theoretical results is less than 18%. The ultimate bearing capacity of IPGC-reinforced foundations decreases with larger geocell diameters. When the diameter of the geocell exceeds 1.8 times the foundation width, the confinement effect of IPGC becomes negligible. The findings of this study offer a robust analytical equation for predicting IPGC-reinforced foundations, along with valuable insights into the efficacy of IPGC reinforcement in enhancing foundation stability.

AI based optimal analysis of electro-osmotic peristaltic motion of non-Newtonian fluid with chemical reaction using artificial neural networks and response surface methodology

PurposeThe present work is devoted to investigating the sensitivity analysis of the electroosmotic peristaltic motion of non-Newtonian Casson fluid with the effect of the chemical reaction and magnetohydrodynamics through the porous medium. The main focus is on flow efficiency quantities such as pressure rise per wavelength, frictional forces on the upper wall and frictional forces on the lower wall. This initiative is to bridge the existing gap in the available literature.Design/methodology/approachThe governing equations of the problem are mathematically formulated and subsequently simplified for sensitivity analysis under the assumptions of a long wavelength and a small Reynolds number. The simplified equations take the form of coupled nonlinear differential equations, which are solved using the built-in Matlab routine bvp4c. The response surface methodology and artificial neural networks are used to develop the empirical model for pressure rise per wavelength, frictional forces on the upper wall and frictional forces on the lower wall.FindingsThe empirical model demonstrates an excellent fit with a coefficient of determination reaching 100% for responses, frictional forces on the upper wall and frictional forces on the lower wall and 99.99% for response, for pressure rise per wavelength. It is revealed through the sensitivity analysis that pressure rise per wavelength, frictional forces on the upper wall and frictional forces on the lower wall are most sensitive to the permeability parameter at all levels.Originality/valueThe objective of this study is to use artificial neural networks simulation and analyze the sensitivity of electroosmotic peristaltic motion of non-Newtonian fluid with the effect of chemical reaction.

Interaction of surface water waves with partial porous structure and floating elastic plate in the presence of sea wall

ABSTRACT This study proposes a model composed of either bottom-standing porous structure (BSPS) or surface-piercing porous structure (SPPS) in combination with an elastic plate (EP) placed at a distance from one another to protect a sea wall. The study uses the governing equation and the boundary conditions to coin a system of equations, and the system of equations is solved to identify the hydrodynamics coefficients. Further, it is noticed that length, frictional coefficient, porosity of the porous structure, and flexural rigidity of EP play a crucial role in reducing the force on the sea wall, water elevation and plate deflection. The SPPS exhibits a nearly 60% reduction in wall force coefficient due to a 50% increase in wave-damping when compared to BSPS for k 0 H = 0.85. These results are crucial for developing floating structures that can resist harsh wave environments and minimize the effects of waves close to the shore.

Non-isothermal simulation on injection/mold temperatures in liquid composite molding process

Liquid composite molding (LCM) is a leading process for manufacturing polymer materials. The LCM process is optimized by designing injection/mold temperatures in actual production. The variety rule of technics parameters such as temperature, curing degree, viscosity, and pressure in the non-isothermal LCM process is the theoretical basis for injection/mold temperatures design. Due to the typical closed mold operation, numerical simulation is the main tool for studying the LCM process. This article used numerical simulation to study the LCM process of typical 3D component. The variation of technics parameters is studied by setting different injection/mold temperatures. This study finds that temperature gradients and curing degree gradients are easily generated along the resin flow direction inside the component. Increasing the injection temperature is more significantly than mold temperature to reduce the resin viscosity and the maximum pressure inside the mold. Meanwhile, increasing the mold temperature is more beneficial than injection temperature for reducing the surface force of the mold wall. Therefore, it is necessary to optimize the injection/mold temperatures in different application scenarios.

Comparison of frontal crash compatibility metrics between battery-electric and internal-combustion-engine passenger vehicles

Objective The objective of this study was to determine if there are any emerging issues related to battery-electric vehicles’ (BEVs’) geometry, force distribution, and extra weight that may make them more aggressive partners in front-to-front crashes through comparisons of stiffness metrics derived from crash tests. Methods We examined load cell wall data from the National Highway Traffic Safety Administration’s (NHTSA’s) New Car Assessment Program full-width frontal crash test at 56 km/h. Fourteen BEVs, ranging in class from small cars to large SUVs, were compared with 92 internal-combustion-engine (ICE) vehicles, ranging in class from small cars to midsize pickups. We selected vehicles based on the test results available in the NHTSA Vehicle Crash Test Database, and there were no tests of battery-electric (BE) pickups. Data included load-cell-wall force-time histories and longitudinal vehicle acceleration from the body structure. We constructed force-displacement diagrams and calculated static, dynamic, energy-equivalent, and initial front-end-stiffness metrics from load cell wall forces, vehicle acceleration, and static front-end crush measurements for each vehicle. Linear regression models were applied to the metrics for comparison between powertrains. Results BE cars and BE SUVs weighed more than their ICE counterparts, on average 369 kg and 286 kg more, respectively. Initial (200 mm and 400 mm), energy-equivalent and dynamic front-end-stiffness metrics, average height of force, and individual maximum forces, when compared with vehicle shadow, were not statistically different between powertrains. Static stiffness (p = 0.04) and initial stiffness (300 mm; p = 0.05) decreased for BEVs with greater shadow and increased with greater shadow for ICE vehicles. When controlling for vehicle shadow, dynamic crush was greater (p = 0.01), the percentage of center force was lower (p < 0.001), and maximum peak force was higher (p = 0.01) for BEVs compared with ICE vehicles. For the Kia Niro BEV and ICE pair, the 329 kg heavier BEV had a 165 mm longer crush distance, which resulted in lower forces and stiffness metrics compared with the traditional ICE counterpart. Conclusion Overall, this study indicates that current BEVs are not excessively aggressive in terms of stiffness metrics for frontal crash compatibility compared with ICE vehicles.

Shear resistance for lateral force of light-frame wall sheathed with structural particleboard (PB)

The shear resistance of a structural particleboard (PB) wall was evaluated as a means to utilize recycled wood and low-grade logs for long periods. The wall was composed of spruce-pine-fir (SPF) lumber, nails, and structural PB, which was developed by improving the water resistance of default PB. Structural PB has a higher density than OSB, which is a commonly used covering material for light wooden structural walls, so a longer end distance for nailing at edge of sheathing is needed for structural PB. In this study, it was confirmed that structural PB walls sufficiently resisted lateral load when the end distance was 15 mm. In this case, the shear strength, shear modulus, and ductility of the structural PB wall for lateral cyclic load were confirmed as 9.2 kN/m, 2.0 kN/mm, and 6.2, respectively. When compared to the design value, the shear strength value was higher than that of the OSB wall and the plywood wall. The shear modulus was lower than that of OSB walls, but higher than plywood walls. Based on the above results, it was considered that structural PB light-frame wall could be used in residential load-bearing applications.

Aerodynamic characteristics of water droplets on superhydrophobic surfaces

The primary objective of this study is to examine droplet dynamics on superhydrophobic surfaces in order to develop strategies to reduce droplet adhesion. The investigation utilized computational fluid dynamics simulations, employing the unsteady Reynolds-averaged Navier–Stokes equations in conjunction with the volume of fluid method. The central focus of this study pertains to the behavior of two droplets on a substrate characterized by a contact angle of 155° within a two-dimensional computational domain. The parametric studies include analyzing the dynamics of droplets with different freestream velocities, droplet sizes, distances between droplets, and the order in which droplets are arranged. Several key findings emerge from this study, notably the observation of an attractive force between two droplets prior to their coalescence. An attraction force between two water droplets was seen in many cases examined due to flow separation, where negative pressure gradients and recirculation flows affected the droplet farthest from the inlet moving upstream. Additional droplet dynamics include the detachment of droplets from the superhydrophobic substrate, the vorticity development after the droplets, and the subsequent wall forces influenced by parametric studies. These findings highlight the inherent capabilities of treated substrates, including self-cleaning attributes, hydrophobicity, and reduced friction. The potential applications based on this research can influence diverse fields, notably materials science, medicine, and engineering.

Copula-based Bayesian uncertainty quantification framework of SST turbulence model for flow over a Gaussian bump

Quantitatively analyze the uncertainties in turbulence models is of great meaning for research and engineering. In this paper, we develop a Bayesian uncertainty analysis framework based on copulas. The proposed framework is applied to the parametric uncertainty quantification and calibration of the shear-stress transport turbulence model for the flow over a Gaussian bump. A copula function is used to establish the correlation between variables and construct the weight function, which enables greater consideration of Bayesian inference. Prior analysis is conducted based on Sobol indices with the nonintrusive polynomial chaos method, demonstrating the important effects of κ, a1, and β∗ on the flow, both for the wall force coefficients and the Reynolds shear stress. Next, the wall force coefficients and Reynolds shear stress are used as training sets to verify the effectiveness of the method. The results show that modeling the relationship based on copulas is necessary and effective, and that the weight function adaptively balances the influence of physical quantities at different inference locations. The proposed method effectively corrects the computational deviations of the corresponding physical quantities. In addition, the confidence interval for the posterior sample is increased, enhancing the likelihood of obtaining results close to the actual values.

Study of the Mechanical Behavior of Retaining Structures and Adjacent Buildings during the Excavation of Deep and Long Pits

Excavation of deep and long pits can cause strata deformation and settlement of adjacent buildings. The excavation of a deep foundation pit of a nearby building in Zhengzhou City, China, is taken as the research object. The foundation of the foundation pit is an independent foundation under the column, the depth of the foundation pit is 24.5∼26.3 m, and the support form of an underground continuous wall and four internal supports is adopted. The stress and deformation characteristics of retaining structures during the construction of deep and long pits and their impact on the deformation of nearby buildings were studied through on‐site monitoring and finite element simulation. The analysis focuses on the effects of different excavation stages on adjacent structures, with the main conclusions as follows. After excavation, the underground continuous wall far from the building undergoes a “rotating‐kick” displacement, while the underground continuous wall on the side near the building only shows a “kick” displacement. Adjacent buildings have little influence on the distribution of shear force and bending moment of the underground continuous wall of the foundation pit. The first horizontal strut experiences pressure, gradually shifting to tension as excavation continues, with the maximum stress reaching 3.6 × 103 kN. The second, third, and fourth horizontal struts mainly bear compressive forces, increasing with the depth of the struts. The building primarily undergoes settlement in the early stages of deep and long pit excavation. As the excavation progresses, the building points near the pit begin to bulge, but the building corners far from the pit continue to show settlement. During the excavation of the deep and long pit, the differential settlement of the long side of the nearby building first decreases and then increases, and the differential settlement of the short side changes from a slight decrease to a significant increase. The settlement evolution of the building is as follows: overall settlement ⟶ overall uplift ⟶ uplift of the side of the building near the pit ⟶ outward tilting away from the pit. The findings may provide references for designing, constructing, and operating deep and large foundation pits.

Oblique wave trapping by sinusoidal rippled barrier of finite thickness placed on closely spaced semi-circular seabed

The oblique wave trapping by a sinusoidal rippled barrier (SRB) of finite thickness placed far away from a partially reflecting seawall is examined under the assumption of linear potential flow theory. The sinusoidal ripples are identical, and the barrier is installed in the presence of a semi-circular bottom (SCB). As a special case, the wave trapping by a thick non-rippled barrier (NRB) is also studied to show the significance of the ripples on the wave trapping. The multi-domain boundary element method is employed to tackle the wave-trapping performance of the SRB satisfying Darcy's law. Various types of structural configurations, such as (a) SRB alone, (b) SRB placed on SCB with trapping chamber, (c) without trapping chamber, (d) NRB alone, and (e) NRB placed on SCB with trapping chamber, are proposed and evaluated under oblique wave incidence. The correctness of the study results is verified with the available results for specific structural configurations. The effect of wall reflection, chamber length, plate porosity, and plate submergence depth on wave-trapping coefficients (wave reflection and wave run-up) and force coefficients (horizontal force on the wall and vertical force on the barrier) are presented against relative wavelength. The enhanced wave trapping is obtained after installing a SRB when compared with the NRB of finite thickness. The chamber spacing minimizes the trapping coefficients when compared with the non-chamber rippled barrier. The study recommends the SRB with SCB of thickness 0.10≤D/h≤0.15, porosity 20%, width B/h=2, and chamber spacing 1≤L/h≤2 to replace the gravity-type breakwaters to be installed against intermediate and deep-water waves.

Experimental clarification of the lateral performance of squat mud infill walls in the timber frames of traditional Japanese residential houses

This paper presents the experimental results of squat mud infill walls with three different height aspect ratios in the timber frames of traditional Japanese residential houses. The deformation and failure characteristics, lateral load-carrying mechanism, and influence of the height aspect ratio on the lateral behavior of squat mud walls are investigated. We observed that when the height aspect ratio of the mud wall is less than 0.5, the initial failure is dominated by corner crushing rather than by shear failure. The lateral stiffness of the squat mud wall is positively correlated with the wall height, whereas the drift angle corresponding to the bearing capacity exhibits an inverse relationship with the wall height. For a height aspect ratio less than 0.3, the internal deformation of the squat mud wall is primarily driven by the deformation angle related to corner crushing and sliding. However, when the height aspect ratio increases to 0.5, the rotation angle increases significantly. The transformation of the deformation characteristics and internal force distribution of the squat mud wall depends on the interplay between the wall height aspect ratio and friction coefficient between the mud wall and timber frame. Drawing from comparative experiments and internal force analysis, the lateral resistance of the squat mud infill wall can be separated into two groups of elements: Qc and Qc’, stemming from the corner compression between the mud wall and adjacent timber frame or internal timber laths, respectively, which exhibits a significant positive correlation with the wall height; Qf and Qg, attributed to the frictional force of the protruding ends of bamboo laths and the gravitational force of the squat mud wall, respectively, which exhibit a consistent behavior unaffected by alterations in the wall height.

Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel

The unsteady characteristics of the second throat of a transonic wind tunnel have an important influence on the design and test of the wind tunnel. Therefore, the forced oscillation characteristics were studied by a numerical simulation method. The governing equation was the viscous compressible unsteady Navier–Stokes equation. Under the sinusoidal pressure disturbance of the computational domain exit, the shock wave presents a clear forced oscillation state, and the shock wave periodically changes its position. Under a pressure disturbance of 1%, the shock wave displacement reaches 150 mm. Additionally, overshoot occurs when the shock moves upstream or downstream. The shock-boundary layer interference is very sensitive to the motion characteristics of the shock wave, resulting in a transformation of the flow field symmetry. The flow field downstream of the shock wave exhibits periodic structural changes. Compared with the pressure change at the outlet, the pressure change near the shock wave has a phase delay. The increasing disturbance near the shock wave shows a clear amplification effect. The pressure disturbance near the shock wave had an obvious amplification effect, and its fluctuation amount reached 16% under the pressure disturbance of 1%. The variation trend of the second throat wall force, wavefront Mach number, and Mach number in the test section with time is similar to that of the downstream disturbance, but it does not have a complete follow-up effect, which indicates that the pressure disturbance can propagate into the test section through the boundary layer or the shock gap. Nevertheless, the second throat choking can still control the Mach number stability of the test section. The dynamic characteristics of shock oscillation are related to the amplitude and frequency of the applied pressure disturbance. The shock displacement decreases with the increase in the excitation frequency. When the excitation frequency is higher than 125 Hz, the flow field basically does not change.

Estimation of wall forces solely from magnetic measurements: an application to RFX-mod experiment

The estimation of integral wall force using solely magnetic measurement in RFX-mod experiment is presented. The vertical and sideways forces are directly obtained from the magnetic field measured outside the vacuum vessel. Several theoretical predictions related to tokamak are also verified for the reversed field pinch configuration. The contribution of different modes to the force is also considered and analyzed. This method of calculation would be relevant for future nuclear fusion reactors where magnetic measurements will be located only outside the vacuum vessel.

Preparation and in vitro/in vivo characterization of sustained-release ciprofloxacin-carrageenan complex

The goal of the study was to look into drug-polyelectrolyte complexation between ciprofloxacin (Cipro) and λ-carrageenan (CRG), and to employ the complex as a sustained-release matrix. The maximum binding capacity of the complexation was determined using the dialysis bag method and employed to prepare the complex. In comparison to Cipro, CRG, and their physical mixing, the complex was examined using differential scanning calorimetry, Fourier infrared spectroscopy, powder X-ray diffraction, and scanning electron microscopy. Cipro-CRG matrices, manufactured as direct compression tablets based on the greatest binding capacity, were assessed for swelling, erosion and drug release in 0.1 M HCl, in comparison with those of CRG, Hydroxypropyl methylcellulose (HPMC) and Cipro-HPMC matrices. In vivo absorption study comparing the Cipro-CRG matrix to Cipro immediate-release tablet was also carried out.The greatest binding capacity of Cipro to CRG was 55% (w/w). Multiple interactions, including electrostatic interaction, Vander wall forces, and hydrogen bonding, have been proposed to be involved in complexation with drug amorphization. As a result of the complexation, the swelling and erosion properties of CRG changed, with Cipro-CRG matrix showing substantially less swelling and erosion than Cipro-free CRG matrix. Cipro-CRG matrix exhibited swelling and erosion similar to Cipro-HPMC matrix. However, the former matrix demonstrated Cipro release with significantly less burst impact and a significantly slower release rate. Furthermore, Cipro-CRG matrices in vivo demonstrated slow-prolonged oral drug absorption with consequent significant changes in pharmacokinetic parameters in comparison to those obtained for immediate-release tablets.