Plate Column Research Articles

The Effect of Particle Monodispersity in HPLC Column Performance

Many developments in silica particles used in liquid chromatography have been well documented over the years. The move from irregular silica to spherical silica, the decrease in particle size from >5µm particle in HPLC to sub-2-µm particle size in UHPLC, the improved silica purity of type B silica over that of type A silica, and more recently the adoption of superficially porous particles versus traditional fully porous particles. One area of development that has been discussed less and is still open to debate is the particle size distribution (PSD) of these chromatographic materials. In this article, we discuss the move towards improved monodispersity of silica particles for use in high performance liquid chromatography (HPLC) and how the use of monodisperse particles can impact the resulting chromatographic parameters such as reduced plate height and column impedance. On a practical level we review how the reduction of PSD impacts efficiency, backpressure and sensitivity.

A assembled plate column bioreactor for adherent cell culture

The ideal bioreactor should be highly efficient, cost-effective and able to promote cells adhesion growth. In this study, we constructed a plate-tower bioreactor with S-loop in each layer based on multilayer plate bioreactor and plate column theory. Human hepatocellular carcinomas(HepG2) and human normal liver cell L02 (L02) cells were employed evaluation of bioreactor performance. The results show that cells were able to adhere to the plates and the density reached to 1～1.2 × 105/cm2. When circulating flow rate of the reactor is 8 ml/min and the oxygen supply concentration is 40 %, the sufficient material and gas exchange in bioreactor, the amount of albumin, urea and cytochrome P450(CYP450) content in the hyperoxia group were 3.31, 2.58 and 2.6 times higher than that of the control group, there was no obvious cell damage. This condition up the regulation of genes in more metabolic pathways and improved the metabolic capacity of hepatocytes. The single-layer area and the number of bioreactors can be flexibly adjusted, and the manufacturing cost of single-layer is close to that of ordinary plastic cell culture dishes. Either batch or continuous mode can be used in the bioreactor. In view of the above characteristics, the bioreactor is more conducive to practical application.

Functional, radiological, and quality of life outcome of unstable acetabular fracture with quadrilateral plate involvement at a tertiary care center in Jakarta, Indonesia.

Unstable acetabular fracture remains a complex fracture that requires technically demanding surgery for orthopedic surgeons. Quadrilateral plate (QP) fractures of the acetabulum are a challenging group of acetabular fractures to manage. However, the literature regarding the management of these injuries are limited. The QP is a relatively thin medial wall of the acetabulum and intra-articular; thus, anatomical reduction and stable fixation are required for satisfactory outcome. This study aims to determine the functional, radiological, and quality of life outcome of unstable acetabular fracture with QP involvement. This was a retrospective cohort study conducted at Cipto Mangunkusumo General Hospital during the period of 2010-2020. Patients with unstable acetabular fractures with and without QP involvement were included in this study. They were followed up postoperatively at 1, 6, and 12months. Functional outcome was assessed using the Harris Hip Score (HHS), Merle D'Aubigne, and Oxford Hip Score (OHS); while radiology outcome was assessed using Matta Outcome Grading; and quality of life was assessed using the SF-36. This study involved 53 subjects with a median age was 29 (18-75) years of age. Twenty-eight (52.8%) subjects had unstable acetabular fracture with QP involvement. Twenty-five (47.2%) subjects had unstable acetabular fracture without QP involvement. Twenty-five (47.2%) subjects were fixed using quadrilateral hook plate, 3 (5.7%) with infrapectineal plate, 10 (18.8%) with posterior column plate, and 15 (28.3%) with suprapectineal plate. The median intraoperative bleeding in those with unstable acetabular fracture with QP involvement was 600 (300-4000) ml, which was higher than those without QP involvement (400 [100-1700]ml). Those with QP involvement achieved anatomical reduction in 20 (71.4%) subjects. Whereas, the subjects without QP involvement achieved anatomical reduction 23 patients (92%). Subjects with QP involvement had significantly lower functional, radiological, and quality of life outcomes compared to those without quadrilateral plate involvement based on Harris Hip Score (p = 0.046), Merle D'Aubigne (0.001), Oxford Hip Score (0.001), Matta Outcome Grading (0.004), and SF-36 (0.001). Patients with quadrilateral hook plate showed no significant functional, and radiological outcome difference compared to patients with infrapectineal plate based on Harris Hip Score (p = 0.582), Merle D'Aubigne (0.698), Oxford Hip Score (1.000), and Matta Outcome Grading (1.000). In addition, we also found no significant functional, radiological, and quality of life outcome difference between posterior column plate and suprapectineal plate group based on Harris Hip Score (p = 0.200), Merle D'Aubigne (0.643), Oxford Hip Score (0.316), Matta Outcome Grading (1.000), and SF-36 (0.600). Patients with unstable acetabular fracture with quadrilateral plate involvement subject had significantly lower functional, radiological, and quality of life outcomes compared to those without quadrilateral plate involvement. Both quadrilateral hook and infrapectineal plates demonstrated non-significant functional and radiological outcomes difference. Posterior column plate also resulted in the same functional, radiological, and quality of life outcome compared with suprapectineal fixation.

CONVERSION OF WASTE POLYPROPILENE (PP) USING THE ZEOLITE Ni/ZSM-5 TO LIQUID FUEL

The aim of this study was to determine the quality and application of liquid oil produced by pyrolysis catalytic cracking assisted Ni/ZSM-5 from polypropylene (PP) plastic waste using a pilot plant scale pyrolysis reactor. The product of pyrolysis in the form of crude oil is refinery by a distillation bubble cap plate column which consists of 4 trays that are integrated with pyrolysis to minimize energy. The pyrolysis process is performed in a fixed-bed reactor. Plastic waste (250 g PP) and Ni/ZSM-5 catalyst (25 g) are mixed in a reactor at various temperatures of 350, 370, 390, 410, and 430ºC, heated in the reactor with a heating rate 5,3 ºC/minute to produce vapor which will be distilled, and produce the product liquid, gas, and char. The optimal yield of fuel oil at 390ºC is 239 ml of fuel oil/250 g of PP with a conversion of 79.20 %,wt (72%, liquid and 7.20% gas) the rest is char. The characteristics of the fuel oil products obtained are included in the range of gasoline and kerosene-type fuels, with an average yield value of ºAPI in the range of 51-42 for kerosene-type fuel in trays 1 and 2, and for gasoline-type fuel. has an average ºAPI value in the range of 52-63 in trays 3 and 4.

Effect of water and protic solvents on polysaccharide-based column efficiency.

In the present study, polysaccharide-based columns were used to evaluate the efficiency of columns in response to the introduction of water and protic solvents (methanol and ethanol) into the mobile phase, replacing acetonitrile. While increasing water content frequently enhances enantiomer resolution, the inclusion of water, particularly when combined with methanol and ethanol in the mobile phase, has an adverse impact on mass transfer, thus influencing the column plate height. These effects are more pronounced with ethanol, and in many cases, van Deemter plots exhibit the absence of a minimum point optimal in the explored range. Consequently, acetonitrile and its water mixtures are the preferred choices to mitigate these effects for situations in which the chiral column is operated at a relatively high flow rate(>1mL/min in a 4.6mm column).

Experimental Studies on Two-Phase Flow with a Novel Slotted Plate Internal in an Air Pulsed Column

ABSTRACT A novel air pulsed column plate internal featuring plates having concentric circular slots of fixed width (3 mm) is conceptualized, tested, and compared against standard sieve plate internal for counter-current two-phase flow. This new plate design (slotted plates) offers significant intensification in terms of specific interfacial area by as much as ~ 50% vis-à-vis standard sieve plates. The studies are carried out in a 3 inch diameter air pulsed column with tap water as the continuous phase and 30% (v/v) tributyl phosphate in dodecane as the dispersed phase. A high-speed imaging system is used to quantify the state of dispersion and obtain drop size distribution along with Sauter mean drop diameter. The effects of pulsing velocity, dispersed phase velocity and continuous phase velocity on dispersed phase holdup, drop size and consequentially specific interfacial area have been systematically studied for both internals. In all cases, slotted plates are characterized by generation of smaller drops and a higher holdup leading to significant improvement in specific interfacial area. Previously reported correlations for estimating dispersed phase holdup and Sauter mean diameter in pulsed sieve plate columns are found to be inadequate for slotted plate internals. Therefore, new correlations for prediction of holdup and drop diameter have been proposed for the new plate design.

Buckling Analysis of a New Type of Double-Steering Prestressed Plate Column

A new type of dual-steering prestressed plate column is introduced. Compared to the previous prestressed strut column, this proposed column considers both bending and constraints at ends. The calculation results indicated that the support plate significantly improves the stable bearing capacity and buckling performance of the core steel column. When compared to the proposed column, the bearing capacity of the three-transverse prestressed beam column is 1.51 times smaller, the single-transverse prestressed beam column is 2.43 times lower, and the non-prestressed column is 4.51 times smaller. Moreover, this study examines the influences of effective length, buckling mode, stress nephogram detail, and prestress value. It explores the possibility of implementing this new type of dual-steering prestressed plate column in practical engineering. In addition, the variety and mechanical models of prestressed columns are expanded and refined.

Experimental study on seismic behavior of cover-plate connections between steel beams and high strength steel box columns

As one of the beam-to-column fully restrained connections that could shift the plastic hinges of the beam away from the face of the column, cover-plate reinforced connections are expected to be a practical choice for high strength steel frame seismic applications. Five cover-plate reinforced and one unreinforced welded flange-bolted web connection specimens combined with Q355 steel I-shaped beams and Q460 or Q690 steel box columns were designed according to Chinese codes and tested under cyclic loads at full scale. Failure modes, including local buckling of the beam, complete joint penetration (CJP) weld fracture, and column web fracture, were reported. The strength, stiffness, deformation, and energy dissipation features were analyzed. The four cover-plate connections met the AISC requirements for special moment frames (SMF) with maximum story drift angles greater than 0.06 rad and exhibited satisfactory seismic behavior. According to the test results, a limit on the ratio of the diaphragm plate to column plate thickness should be considered when the electroslag welding (ESW) process is used in high strength box columns. The strong panel zone designed with a panel zone resistance ratio (γpz) greater than 1.20 was recommended for box columns with steel strength no less than 690 MPa. Additionally, other design implications of the results were discussed.

A Study on Mechanical Performance of an Innovative Modular Steel Building Connection with Cross-Shaped Plug-In Connector

Modular steel buildings show high assembly degree and fast installation speed. The inter-module connection (IMC) is one of the key technologies that restrict the robustness of modular steel buildings. An innovative IMC with a cross-shaped plug-in connector is proposed, and the connection consists of end plates of columns, the cross-shaped plug-in connector, bolts, cover plates, and one-side bolts. The proposed IMC is easily constructed, and the cross-shaped plug-in connector can improve the shear resistance of the core area. The mechanical model of the proposed IMC is presented, and the panel zone volume modified factor and initial rotational stiffness modified factor are proposed for calculating the shear capacity of the panel zone and the initial rotational stiffness. Numerical simulation was conducted considering the influences of axial compression ratios, sections of beams and columns, and the thickness of the tenon plate of the connector. The bearing capacity of the proposed IMC was analyzed, and the values of the two factors mentioned above were calculated, and their regression formulas are presented. The results show that the sections of beams and columns and the axial compression ratios show great influences on the bearing capacity of the proposed IMC, while the thickness of the tenon of the cross-shaped plug-in connector shows almost no effect. In addition, the sections of beams and columns show great influences on the shear capacity of the panel zone, as well as the initial rotational stiffness of the proposed IMC, while the thickness of the tenon of the cross-shaped plug-in connector and the axial compression ratios show little effect and almost no effect, respectively. Furthermore, the bending moment limit of the beam end of the proposed IMC is suggested to be 0.6 times the resistance bending moment, and the proposed IMC is considered to be a rigid connection or inclined to a rigid connection The proposed IMC has good mechanical performance, and design recommendations are presented.

Influence of Column Base Connections on the Cyclic Loading Performance of Double-Jointed Engineered Bamboo Columns

The cyclic loading performance of bamboo double-jointed components of different column base connection types was investigated through reversed cyclic loading tests and finite element analysis. Test results indicated that the types of column base connections played an important role in the failure modes of the engineered bamboo double-jointed columns: for an encased steel plate column base connection, the main failure mode was tensile fracture failure of the bamboo scrimber section at the bottom of the cladding plate; for a slotted-in steel plate column base connection, the main failure mode was splitting failure of the bamboo scrimber cross-grain at the bolt connection line at the bottom of the sheathing plate. The initial stiffness of the encased steel plate column base connection specimen was 41.8% higher than that of the slotted-in steel plate column base connection specimen, with the two specimens having similar average bearing capacities. The ductility ratio of the two specimens was below 3.0 due to the brittle failure nature of the engineered bamboo connections. The finite element model accurately predicted the ultimate bearing capacity of the double-jointed bamboo column members. The modeling error was within 12%, which was sufficient to satisfy the accuracy requirements for engineering purposes.

Tensile behaviour of asymmetric bolted square hollow section column splices

In traditional end plate column splices, bolts are placed double symmetrically on the four sides of square hollow sections (SHS). In order to reduce the required gap between the façade and the column, the end plate could be flushed on one or two sides of SHS for the column along the façade or at the corner of a building, respectively. However, the analytical solution (Component method) for the traditional column splice is not applicable in this case. This paper addresses the tensile behaviour of asymmetric column splices, where a cover plate is used on the end plate flushed side. Columns are dominantly loaded in compression and bending, but to verify the component’s interaction, the column splices are tested in tension in this paper. The tensile behaviour is investigated through the experiment, the finite element (FE) analysis, and the component method. Eight tensile tests were conducted. The FE model is validated against the experiment. A bi-linear model is employed to characterise the column splice yield resistance, which shows a good agreement with the ultimate resistance of the FE model using a constitutive model without strain hardening. The effective length measured from the FE model is approximately two times that calculated by equations. Using the measured effective length, the component method predicts the characterised yield resistance well (average 13% lower). In comparison, the resistance is underestimated by 35% on average if the calculated effective length is used.

Seismic performance of bolted T-stub Beam-to-Box column connection

Using internal continuity plates in box columns due to accessibility problems and complicated detailing of connection was perceived as fraught with shortcomings and limitations. To overcome this deficiency, the effectiveness of external continuity plates in conjugation with T-stub connectors in I-beam to box-column connections under cyclic action is investigated in this study. Three damage control strategies based on the fuse action of T-stubs (T-F), strengthening the connections (T-S), and using reduced beam section (RBS) connections (T-R) are pursued and are compared to a corresponding end-plate connection (E). Nonlinear finite element analyses are conducted using the ABAQUS/STANDARD software on the connections under the qualification cyclic loading conditions to elucidate all the main seismic behavioral aspects, including the strength, initial stiffness, energy dissipation, ductility, von-Mises stress, and equivalent plastic strain distributions of models. First, the accuracy of numerical models is validated by a series of available experimental results. Then, a parametric study is performed on the effects of the moment ratio of the beam to column, the number of continuity plates, stiffeners embedded on the beam, and using high strength materials on the seismic performance of the connections. From the results, it is found that the T-S model was the most efficient among the different connections studied, supplying the stiffness, strength, energy absorption, and ductility increases by 2%, 21%, −17%, and 22%, respectively with respect to the E model, satisfying the requirements of AISC Seismic Provisions for SMF. Increasing the beam-to-column moment ratio and the number of continuity plates, had limited effects by less than 10% on the seismic performance of the connections. In the absence of continuity plates, the connections exhibited worse inelastic seismic performance with decreases in stiffness, strength, and energy dissipation up to 67%, 44%, and 74%, respectively. The T-F connection gained a 13% strength increase and satisfied the AISC requirements when high-strength T-stubs are used. Based on the numerical observations, design strength and rotational stiffness of the proposed connections on the component-based joint design strategies, are finally outlined.

Effect of thermal dynamics and column geometry of pressure swing adsorption on hydrogen production from natural gas reforming

The present study investigates hydrogen purification from a surrogate gas using spent coffee grounds as a medium. The study was conducted using Aspen adsorption software, and the process was examined under isothermal, adiabatic, and non-adiabatic conditions. The surrogate gas mixture comprised 70% hydrogen and 30% carbon dioxide and was introduced into two stainless steel chambers containing the coffee media. The pressure was altered from 101.3 to 150 kPa as the chamber underwent the adsorption process. At an adsorption time of 60 s, all three conditions exhibited similar levels of purity and recovery, with the isothermal mode producing the highest values. Additionally, the effect of heat dissipation and column geometry on the adsorption performance was investigated by comparing the conventional isothermal column with the rectangular non-adiabatic plate column. The plate column is rectangular, with two chambers that use the heat generated during adsorption to regenerate the opposite column during the blowdown step. This effect was evaluated under different adsorption times of 30–180 s and hydrogen feed concentrations of 70–90%. The plate column had higher hydrogen purity and recovery of 99.99% and 77.41%, respectively, compared to 99.56 and 71.12% of the cylindrical column. Overall, the results indicate that spent coffee grounds can be effectively used as a medium to purify hydrogen from a surrogate gas mixture. A rectangular non-adiabatic plate column can further enhance the purification process by improving purity and recovery responses.

Separation of Rare Earth Elements in Multistage Extraction Columns in Chromatography Mode: Experimental Study and Mathematical Simulation

The application of liquid–liquid chromatography principles to solvent extraction processes in hydrometallurgy can greatly simplify rare earth metal separation technologies by separating multicomponent mixtures in one technological operation. In this study, the chromatographic separation of rare earth elements (REEs) in multistage extraction columns was experimentally studied under conditions of impulse sample injection—single and multiple loading of large volumes of metal salt solution into the installation. The results obtained showed the feasibility of operating sieve plate extraction columns in the liquid–liquid chromatography mode. A closed-loop recycling technology is proposed for the separation of rare earth elements in multistage extraction columns operating in the liquid–liquid chromatography mode. For further development and industrial implementation of this technology, experimental studies should be conducted on intensified multistage extraction columns, such as sectioned columns with agitators and vibrating plate columns. Computer simulation of the chromatographic separation of rare earth elements by closed-loop recycling liquid–liquid chromatography was carried out.

Space Charge Characteristics of Electrothermally Aged Oil-Paper Insulation Under Slightly Nonuniform Electric Field

To study the change characteristics of space charge in oil paper insulation under a slightly non-uniform electric field and a uniform electric field, the existing space charge measuring device was improved, and sphere–plate and column–plate electrode models were prepared. Oil paper insulation samples at different aging stages were obtained via electrothermal aging. The real-time waveforms of the space charge distribution in the samples at different aging stages were measured in the process of polarization with a direct-current (DC) voltage and depolarization with a DC voltage, and the effects of different electric-field types on the charge distribution and motion characteristics of oil paper insulation samples at different aging stages were examined. The results indicated that the existence of a slightly non-uniform electric field accelerated the change in the charge-density peak at the interface and increased the fluctuation range of the charge-density curve in the process of applying a DC voltage. With the aggravation of electrothermal aging, the amount of charge injected into the sample increased, and the slightly non-uniform electric field intensified this process, affecting the accumulation and dissipation of space charge in the sample. Electrothermal aging increased the trap distribution density and energy-level depth. However, for an oil paper insulation sample at the same aging stage, compared with the uniform electric field, the slightly non-uniform electric field had no obvious effect on the trap energy-level depth, but it increased the amount of trapped charge and changed the trap density distribution in the sample. The results of this study provide a theoretical basis for examining the influence of slightly non-uniform electric fields on the space charge distribution characteristics of oil paper insulation subjected to AC/DC combined electrothermal aging.

A general scaled model design method of stiffened plate subjected to combined longitudinal compression and lateral pressure considering the ultimate strength and collapse modes

A general and efficient scaled method for stiffened plates subjected to combined longitudinal compression and lateral pressure is proposed based on slenderness, simply by adjusting the number of stiffeners. The design method makes it easier to determine the dimensions of the scaled model for a given scale ratio compared with the previously proposed method. The emphasis is on the influence of the plate slenderness, the column slenderness, and the non-dimensional parameter of the lateral pressure on the ultimate strength. By maintaining the consistency of the plate slenderness and column slenderness, the proposed method is applicable for designing scaled models with materials of different yield stresses and Young's moduli. A similar effect of the lateral pressure on the ultimate strength of the prototype and scaled models is achieved by maintaining the non-dimensional parameter. In addition, the applicability of the scaled method to the initial deflection is considered, which provides a reference for similar models. The similitude of the scaled method is verified for several typical buckling modes, including the beam–column, tripping, web and overall collapse modes. Given the numerical results, the proposed general and fast scaled method can provide reasonable dimensions of scaled stiffened plates subjected to combined loads.

Double-column Die-punch fractures of distal radius treated with butterfly plate fixation via Henry approach

To explore clinical effect of open reduction and internal fixation with Henry's approach butterfly plate in treating double-column Die-punch fractures of distal radius. From January 2018 to June 2021, 26 patients with double-column Die-column distal radius were treated with open reduction and internal fixation through Henry's surgical approach and using distal radius volar column plate(butterfly plate), including 14 males and 12 females, aged from 20 to 75 years old with an average age of (44.2±3.4) years old. Postopertaive complications were observed, Gartland-Werley score at 12 months after opertaion was used to evaluate wrist joint function. All 26 patients were followed up from 10 to 18 months with an average of(13.4±0.8) months. All fractures were obtained fracture union, the time ranged from 8.5 to 15.8 weeks with an average of (11.4±0.5) weeks. All incisions healed at stageⅠwithout infection, nerve injury and internal fixation failure occurred. Postoperative Gartland-Werley score at 12 months was (3.65±0.36), and 16 patients got excellent result, 8 good and 2 moderate. Open reduction and internal fixation with butterfly plate for the treatment of double-column Die-punch fractures of the distal radius through volar Henry approach could obtain satisfactory clinical outcomes.

Solvent effects and mass transfer on aroma extraction during solid-state distillation

Steam distillation is an important unit operation to extract valuable compounds from natural solid-state substrates. Solid-state distillation with steam can extract aroma from fermented solid substrate such as fermented grains of Chinese liquor fermentation. However, this procedure is still operated based on generations of empirical skills rather than a technique under process control based on scientific principles. The resulting drawback is poor mass and heat transfer with undesired consequences concerning productivity, quality and sustainability. Mathematical modelling can be a powerful tool to get insight into such an empirical process for potential rational design, optimization and control. Therefore, we established a mathematical model to describe the mass transfer based on kinetic parameters. The simulation results show that the distillation had a natural column plate structure that more effectively concentrated compounds. Furthermore, this structure resulted in a high ethanol concentration in the distillate. To evaluate subsequent effect of high ethanol concentration, we analysed aroma compounds in the distillates under simulated conditions with or without ethanol. The hydrophobic compounds were fitted well under conditions with ethanol, whereas hydrophilic compounds had similar outcomes under both conditions. The results show that ethanol could accelerate the release of hydrophobic compounds in Chinese liquor distillation. Therefore, solvent could be one of the important factors to optimize the distillation process. Our findings provide a reference for improving the extraction during solid-state distillation.

Mechanisms of plasticity development and energy dissipation on concrete-encased steel plate shear wall with boundary steel frame under cyclic loading

Steel frame infilled with composite plate shear wall (SF-CPSW) is an efficient lateral load resisting structure with significant ductility and energy dissipation capacity. In this paper, CPSW comprises the infill steel plate, encased concrete panel and headed studs. The steel frames (SFs) are expected to sustain the vertical load, while as the boundary members of the CPSW, they also influence the lateral behaviors of structure. However, the research on the interactions or plasticity development of SF-CPSW is limited. Thus, its energy dissipation mechanism is unclear to date. This paper conducts finite element analyses on the hysteresis performance and energy dissipation mechanism of SF-CPSW structure under cyclic loading. The hysteresis and skeleton of lateral load-drift ratio responses, distributions and developments of internal forces, stresses and strains and the energy assignments are studied to reveal the mechanisms of lateral load-resisting and plasticity development of SF-CPSW. The effects of steel plate thickness, beam cross-section, column cross-section and concrete panel thickness on the hysteresis performance and energy assignment are investigated to propose the energy dissipation mechanism and associated design methods. The results indicate that the energy dissipation of SF-CPSW is governed by the plastic shearing of infill steel plate and beam web due to the shear force transfers and bending restraints from CPSW to the steel frame. Besides, the columns resist portions of lateral load under such interactions. The structural energy dissipation should develop successively by the shear yielding of steel plate, the shear yielding of beam and column, the flexural yielding of beam, the plastic buckling of steel plate and the flexural yielding of column. As the major members for energy dissipation, the yield shear strength of beam should be higher than 27.5% yield shear strength of infill steel plate.

Biomechanical study of different fixation constructs for anterior column and posterior hemi-transverse acetabular fractures: a finite element analysis

BackgroundTo compare the biomechanical properties and stability, using a finite element model, of four fixation constructs used for the treatment of anterior column and posterior hemi-transverse (ACPHT) acetabular fractures under two physiological loading conditions (standing and sitting).MethodsA finite element model simulating ACPHT acetabular fractures was created for four different scenarios: a suprapectineal plate combined with posterior column and infra-acetabular screws (SP-PS-IS); an infrapectineal plate combined with posterior column and infra-acetabular screws (IP-PS-IS); a special infrapectineal quadrilateral surface buttress plate (IQP); and a suprapectineal plate combined with a posterior column plate (SP-PP). Three-dimensional finite element stress analysis was performed on these models with a load of 700 N in standing and sitting positions. Biomechanical stress distributions and fracture displacements were analysed and compared between these fixation techniques.ResultsIn models simulating the standing position, high displacements and stress distributions were observed at the infra-acetabulum regions. The degree of these fracture displacements was low in the IQP (0.078 mm), as compared to either the IP-PS-IS (0.079 mm) or the SP & PP (0.413 mm) fixation constructs. However, the IP-PS-IS fixation construct had the highest effective stiffness. In models simulating the sitting position, high fracture displacements and stress distributions were observed at the regions of the anterior and posterior columns. The degree of these fracture displacements was low in the SP-PS-IS (0.101 mm), as compared to the IP-PS-IS (0.109 mm) and the SP-PP (0.196 mm) fixation constructs.ConclusionIn both standing and sitting positions, the stability and stiffness index were comparable between the IQP, SP-PS-IS, and IP-PS-IS. These 3 fixation constructs had smaller fracture displacements than the SP-PP construct. The stress concentrations at the regions of quadrilateral surface and infra-acetabulum suggest that the buttressing fixation of quadrilateral plate was required for ACPHT fractures.