Compression Side Research Articles

BUCKLING DELAMINATION IN COMPRESSED NO-TENSION HOMOGENEOUS BRITTLE BEAM-COLUMNS REINFORCED WITH FRP

The main issue of this paper is the instability of no-tension structural members reinforced with FRP. This study concerns the instability of FRP reinforcement. The primary instability problem of a compressed element involves the partialization of the inflex section. In particular, in the case of a compressed slender element reinforced on both tense and compressed side FRP delamination phaenomenon could occur on the latter.
 This entails the loss of the reinforcement effectiveness in the compressed area for nominal load values much lower than material effective strength. Therefore, structural elements or portions thereof which absorb axial components in the direction of the reinforcement may exhibit relatively modest performance with respect to the unreinforced configuration.
 By employing a no-tension material linear in compression, an analytical solution for FRP buckling delamination length is provided.
 The main objective of this paper is to provide a simplified tool that allows to evaluate the critical load of the reinforced beam-column and to predict the tension at which delamination and the loss of effectiveness of reinforcement in the compressed area could occur.

Development of Unidirectional CFRP Reinforced Aluminum Bumper Reinforcement

<div class="section abstract"><div class="htmlview paragraph">Since bumper reinforcements are positioned at front/rear ends of vehicles, weight reduction of the bumper reinforcements enhances vehicle dynamic performance by reducing a yaw moment of inertia. CFRP (Carbon Fiber Reinforced Plastic) composites are attractive lightweight materials due to their excellent specific strength and rigidity. However, because of their relatively high cost, applications of CFRP materials to vehicle structural parts are limited. In this study we have developed a lightweight, structural part, which consists of a thin-walled Al (Aluminum) bumper reinforcement with a UD (Unidirectional)-CFRP sheet. The intention is to prevent an increased part cost by reducing the amount of Al and by minimizing the amount of CFRP. Compared to Al, UD-CFRP sheets have even higher tensile strength and modulus. When vehicles crash, bumper reinforcements may be subjected to bending force. If a UD-CFRP sheet is adhered on the tensile side of an Al bumper reinforcement, not only Al thickness on the tensile side, but also thickness on the compression side can be reduced due to movement of the bending neutral axis. In this design with a multi-material structure, bending strength of the developed part can’t be predicted by a full plastic moment which could normally be used to predict metal parts’ bending strength under large deformation. We employed a novel cross-section design method which can be used to predict bending strength of CFRP reinforced metal structures under large deformation. To validate the calculation method, three-point bending tests on the parts were carried out. Experimental data of bending strength were in the range of predicted bounds. Also, in order to launch the developed part, robustness of part’s performance was evaluated. Finally, the part was adapted to the rear bumper reinforcement of LEXUS RC-F. The part weight is 11 % lighter compared to the conventional, all-Al, bumper reinforcement.</div></div>

Strength characterization of exposed column base plates subjected to axial force and biaxial bending

Exposed Column Base Plate (ECBP) connections are commonly used to connect columns in steel moment frames to concrete footings. Although their response under uniaxial bending and axial force is well established, only limited research and design guidance exists for their response under biaxial bending. A new method is presented to characterize the internal stress distribution and anchor rod forces in ECBP connections subjected to biaxial bending and axial compression. The method is based on (and validated against) finite element simulations on ECBP connections; these simulations are, in turn, validated against experimental data. The proposed method extends the American Institute of Steel Construction’s Design Guide One approach (for uniaxially loaded ECBP connections) to biaxial loading. This involves addressing indeterminacies that arise due to the engagement of additional anchor rods (as compared to the uniaxial case). The proposed method accomplishes this through the enforcement of a predetermined pattern of tensile forces in the anchor rods, in conjunction with a stress block on the compression side. The method is demonstrated to predict anchor forces with good accuracy across a range of configurations (including column and base plate size) and loadings (level of axial force and bending angle). Implications for the design of ECBP connections are outlined along with limitations of the proposed approach.

Effect of TNF-α on osteocyte RANKL expression during orthodontic tooth movement

Background/purposeOrthodontic tooth movement (OTM) is facilitated by two events; bone resorption on the compression side and bone formation on the tension side simultaneously termed bone remodeling. Osteocytes play a critical role in bone remodeling during OTM, as they have been described as the critical source of nuclear factor-κB ligand (RANKL) necessary for bone remodeling during OTM. Tumor necrosis factor (TNF)-α is a cytokine that acts by amplifying RANKL expression in osteocytes. In this study, we evaluated the effects of TNF-α on RANKL expression in osteocyte during OTM. Materials and methodsWe assessed whether TNF-α influenced RANKL expression in osteocyte during orthodontic tooth movement by using wild-type (WT) and TNF receptor I and II deficient (TNFRsKO) mice. A Nickel-titanium closed coil spring was attached to the maxillary alveolar bone near the incisors and the upper left first molar, and the first molars were moved mesially in WT and TNFRsKO mice. After OTM, the number of RANKL-positive osteocytes in the alveolar bone was evaluated by immunohistochemistry. ResultsThe number of RANKL-positive osteocyte in the alveolar bone significantly increased in WT mice than in TNFRsKO mice after OTM. ConclusionThe results indicate that TNF-α induces the expression of RANKL in osteocyte during OTM.

Punching shear behaviour of interior slab-column connections strengthened by steel angle plates

The present paper is concerned with a series of tests on reinforced concrete flat slabs to examine the behaviour of interior slab-column connections employing steel angle plates and high strength bolts as strengthening elements. The angle plates were bolted to the column faces and slab at both tension and compression sides. The shorter leg of the angle plate attached to the column face acts as a column capital of an equivalent concrete width whilst the longer leg is treated as a drop panel of an equivalent concrete depth. Four flat slabs of practical size were constructed and tested to failure under shear load applied through the column. The strengthening technique has effectively turned the final mode of failure from punching shear to flexure-induced punching outside the strengthened zone. Such slab system has shown appreciable increases in the deformation capacity, stiffness, energy absorption and particularly load-carrying capacity with 20%, 24%, 209% and 51% in average, respectively over that of the unstrengthened slab. Non-linear finite element models were developed, analysed and validated against the test results, only to find that both findings were found to be in a good agreement. A parametric study was performed to investigate the effects of bolts strength, bolts spacing and dimensions of angle plates on the ultimate load behaviour of the slab. A simple theoretical method based on yield line theory to predict the flexural capacity of the strengthened slab is also outlined. In addition, the tests and numerical results are compared with the values predicted using the ACI design code.

METAL: The Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud Hubble Program. II. Variations of Interstellar Depletions and Dust-to-gas Ratio within the LMC

Abstract A key component of the baryon cycle in galaxies is the depletion of metals from the gas to the dust phase in the neutral interstellar medium (ISM). The METAL (Metal Evolution, Transport, and Abundance in the Large Magellanic Cloud) program on the Hubble Space Telescope acquired UV spectra toward 32 sight lines in the half-solar metallicity LMC, from which we derive interstellar depletions (gas-phase fractions) of Mg, Si, Fe, Ni, S, Zn, Cr, and Cu. The depletions of different elements are tightly correlated, indicating a common origin. Hydrogen column density is the main driver for depletion variations. Correlations are weaker with volume density, probed by C i fine-structure lines, and distance to the LMC center. The latter correlation results from an east–west variation of the gas-phase metallicity. Gas in the east, compressed side of the LMC encompassing 30 Doradus and the southeast H i over-density is enriched by up to +0.3 dex, while gas in the west side is metal deficient by up to −0.5 dex. Within the parameter space probed by METAL, no correlation with molecular fraction or radiation-field intensity are found. We confirm the factor of three to four increase in dust-to-metal and dust-to-gas ratios between the diffuse (log N(H) ∼ 20 cm−2) and molecular (log N(H) ∼ 22 cm−2) ISM observed from far-infrared, 21 cm, and CO observations. The variations of dust-to-metal and dust-to-gas ratios with column density have important implications for the sub-grid physics of chemical evolution, gas and dust mass estimates throughout cosmic times, and for the chemical enrichment of the Universe measured via spectroscopy of damped Lyα systems.

Evaluation of interleukin-1 beta and the ratio of interleukin-1 beta to interleukin-1 receptor antagonist in gingival crevicular fluid during orthodontic canine retraction.

Orthodontic tooth movement (OTM) is a complex phenomenon mediated by cytokines, of which interleukin-1 beta (IL‑1β) is potently involved in the remodeling of the periodontal ligament (PDL) and bone. Whether the pattern of IL‑1β release differs at the sides of tension and compression is not yet clarified. The aim of the present study was to evaluate the level of IL‑1β and the ratio of IL‑1β to interleukin-1 receptor antagonist (IL‑1RA) in gingival crevicular fluid (GCF) at the tension and compression sides during orthodontic canine retraction. Seventeen patients scheduled for orthodontic treatment with bilateral extraction of maxillary first premolars and canine retraction were enrolled. Tooth 2.3 was retracted, teeth 1.3 and 3.3 served as controls. Gingival crevicular fluid samples were collected from the tension and compression sides of each tooth at baseline (before the 1st activation - day 0) and at days 2 and 7, and then again before the 2nd activation (day 28) and at days 30 and 35. The levels of IL‑1β and IL‑RA were evaluated with the enzyme-linked immunosorbent assay (ELISA). After the 1st activation, a statistically significant increase in the level of IL‑1β was observed at teeth 2.3 (p < 0.03 mesially and p < 0.05 distally) and 1.3 (p < 0.05 mesially and distally), both at the tension and compression sides. The 2nd activation resulted in a gradual increase in the IL‑1β level at both canines; however, statistical significance was reached only for tooth 2.3 (p < 0.05 mesially and p < 0.02 distally). In terms of the IL‑1β/IL‑1RA ratio, a significant increase was observed only at the compression side of the experimental tooth (p < 0.01). An increase in the IL‑1β level in GCF was observed both at the tension and compression sides of the actively retracted canine 2.3 as well as the contralateral canine 1.3; a significant rise in the IL‑1β/IL‑1RA ratio was noted only at the compression side of the experimental tooth 2.3, indicating the zone of active bone resorption.

Roles of autophagy in orthodontic tooth movement

Orthodontic tooth movement (OTM) relies on efficient remodeling of alveolar bone. While a well-controlled inflammatory response is essential during OTM, the mechanism regulating inflammation is unknown. Autophagy, a conserved catabolic pathway, has been shown to protect cells from excess inflammation in disease states. We hypothesize that autophagy plays a role in regulating inflammation during OTM. A split-mouth design was used to force load molars in adult male mice, carrying a GFP-LC3 transgene for invivo detection of autophagy. Confocal microscopy, Western blot, and quantitative polymerase chain reaction analyses were used to evaluate autophagy activation in tissues of loaded and control molars at time points after force application. Rapamycin, a Food and Drug Administration-approved immunosuppressant, was injected to evaluate induction of autophagy. Autophagy activity increases shortly after loading, primarily on the compression side of the tooth, and is closely associated with inflammatory cytokine expression and osteoclast recruitment. Daily administration of rapamycin, an autophagy activator, led to reduced tooth movement and osteoclast recruitment, suggesting that autophagy downregulates the inflammatory response and bone turnover during OTM. This is the first demonstration that shows that autophagy is induced by orthodontic loading and plays a role during OTM, likely via negative regulation of inflammatory response and bone turnover. Exploring roles of autophagy in OTM holds great promise, as aberrant autophagy is associated with periodontal disease and its related systemic inflammatory disorders.

Albemarle reports 4Q and full year 2020 results: Catalysts

The present paper is concerned with a series of tests on reinforced concrete flat slabs to examine the behaviour of interior slab-column connections employing steel angle plates and high strength bolts as strengthening elements. The angle plates were bolted to the column faces and slab at both tension and compression sides. The shorter leg of the angle plate attached to the column face acts as a column capital of an equivalent concrete width whilst the longer leg is treated as a drop panel of an equivalent concrete depth. Four flat slabs of practical size were constructed and tested to failure under shear load applied through the column. The strengthening technique has effectively turned the final mode of failure from punching shear to flexure-induced punching outside the strengthened zone. Such slab system has shown appreciable increases in the deformation capacity, stiffness, energy absorption and particularly load-carrying capacity with 20%, 24%, 209% and 51% in average, respectively over that of the unstrengthened slab. Non-linear finite element models were developed, analysed and validated against the test results, only to find that both findings were found to be in a good agreement. A parametric study was performed to investigate the effects of bolts strength, bolts spacing and dimensions of angle plates on the ultimate load behaviour of the slab. A simple theoretical method based on yield line theory to predict the flexural capacity of the strengthened slab is also outlined. In addition, the tests and numerical results are compared with the values predicted using the ACI design code.

Osteoclastic effects of mBMMSCs under compressive pressure during orthodontic tooth movement

BackgroundDuring orthodontic tooth movement (OTM), alveolar bone remodelling is closely related to mechanical force. It is unclear whether stem cells can affect osteoclastogenesis to promote OTM. This study aimed to investigate the role of mouse bone marrow mesenchymal stem cells (mBMMSCs) under compression load in OTM.MethodsA mouse OTM model was established, and GFP-labelled mBMMSCs and normal saline were injected into different groups of mice by tail vein injection. OTM distance was measured using tissue specimens and micro-computed tomography (micro-CT). The locations of mBMMSCs were traced using GFP immunohistochemistry. Haematoxylin-eosin staining, tartrate-resistant acid phosphate (TRAP) staining and immunohistochemistry of Runx2 and lipoprotein lipase were used to assess changes in the periodontal ligament during OTM. mBMMSCs under compression were co-cultured with mouse bone marrow-derived macrophages (mBMMs), and the gene expression levels of Rankl, Mmp-9, TRAP, Ctsk, Alp, Runx2, Ocn and Osterix were determined by RT-PCR.ResultsTen days after mBMMSCs were injected into the tail vein of mice, the OTM distance increased from 176 (normal saline) to 298.4 μm, as determined by tissue specimen observation, and 174.2 to 302.6 μm, as determined by micro-CT metrological analysis. GFP-labelled mBMMSCs were mostly located on the compressed side of the periodontal ligament. Compared to the saline group, the number of osteoclasts in the alveolar bone increased significantly (P < 0.01) on the compressed side in the mBMMSC group. Three days after mBMMSC injection, the number of Runx2-GFP double-positive cells on the tension side was significantly higher than that on the compression side. After applying compressive force on the mBMMSCs in vitro for 2 days, RANKL expression was significantly higher than in the non-compression cells, but expression of Alp, Runx2, Ocn and Osterix was significantly decreased (P < 0.05). The numbers of osteoclasts differentiated in response to mBMMs co-cultured with mBMMSCs under pressure load and expression of osteoclast differentiation marker genes (Mmp-9, TRAP and Ctsk) were significantly higher than those in mBMMs stimulated by M-CSF alone (P < 0.05).ConclusionsmBMMSCs are not only recruited to the compressed side of the periodontal ligament but can also promote osteoclastogenesis by expressing Rankl, improving the efficiency of OTM.

Notch signaling inhibition protects against root resorption in experimental immature tooth movement in rats

This study aimed to build an experimental immature tooth movement model and verify less resorption of incompletely developed roots than those fully developed during the same orthodontic treatment, followed by investigating the cellular and molecular mechanism. The development of Wistar rat tooth was investigated using invivo microcomputed tomography and hematoxylin and eosin staining to decide the optimal ages of rats for immature tooth and mature tooth groups. The rats in the immature tooth and mature tooth groups were divided into experimental, sham control, and blank control groups. After orthodontic treatment for 3weeks, the mesial root volume, crown movement distance, neck movement distance, root inclination, and apical distance were measured by microcomputed tomography. The expressions of TRAP, Jagged1, Notch2, IL-6, and RANKL were analyzed by immunohistochemical staining and real-time polymerase chain reaction. The repair of root resorption was also investigated after removing orthodontic force for 3 and 6weeks. The root achieved the development stage around 10weeks, so 4-week-old rats and 10-week-old rats were used in the immature tooth group and mature tooth group, respectively. The volume of root resorption in the experimental immature tooth group was 0.0869±0.0244mm3, which was less than that in the mature tooth group (0.1218±0.0123mm3)(P<0.001). Immature tooth movement decreased TRAP-positive odontoclasts on the compression side while having no statistically significant effect on osteoclasts. The protein expression of Jagged1, Notch2, IL-6, and RANKL in the mature tooth group increased significantly compared with the immature tooth group, not only on the compression side but also on the tension sides. The mRNA expression of Jagged1, Notch2, and RANKL was significantly lower in the immature tooth group, whereas the expression of IL-6 had no significance but a strong tendency. The root volume after repairing for 3weeks was still less than that of blank control, whereas after repairing for 6weeks, the difference was not statistically significant. The experimental immature tooth movement model for the Wistar rat was achieved for the first time. The immature tooth will suffer less root resorption than the mature tooth, which may be due to odontoclastogenesis inhibition by decreased expression of Jagged1/Notch2/IL-6/RANKL signaling.

Behavior of eccentrically loaded normal weight concrete encased steel columns at elevated temperature

This paper presents an experimental investigation on the behavior of normal weight concrete encased steel (CES) columns eccentrically loaded and exposed to different elevated temperature using an electrical furnace. Four CES columns were tested with cross section dimensions of 150 ×150 mm (width× depth) and 1250mm total length and encased a steel section with dimensions of 70×60× 4×4 mm (total height× flange width× flange thickness× web thickness. The top and bottom ends of the columns were designed as corbels to prevent the premature local bearing failure at the concrete due to axial load. The corbels had a cross section dimensions equal to 240mm ×150mm (width × depth) with a distance between them equal to750mm. The experimental results have revealed that all CES columns have failed by flexural buckling failure mode with concrete crushing at the middle third of the compression side column accompanied with local buckling of the steel section flange. Analysis of the test results has also indicated that when the exposed temperature increases, the failure load considerably decreases. Where, the failure load of the CES columns has decreased by 53.6%, 61.2%, and 63.6% compared to the control CES column when they exposed to temperature of 400°C, 500°C, 600°C, respectively.

Effect of Caffeic Acid Phenethyl Ester Provision on Fibroblast Growth Factor-2, Matrix Metalloproteinase-9 Expression, Osteoclast and Osteoblast Numbers during Experimental Tooth Movement in Wistar Rats (Rattus norvegicus).

Objectives To investigate the effect of caffeic acid phenethyl ester (CAPE) provision on matrix metalloproteinase-9 (MMP-9), fibroblast growth factor-2 (FGF-2) expression, osteoclast and osteoblast numbers during experimental orthodontic tooth movement (OTM) in male Wistar rats ( Rattus norvegicus ). Materials and Methods Forty-eight healthy male Wistar rats ( R. norvegicus ), 16 to 20 weeks old with 200 to 250 g body weight (bw) were divided into several groups as follows: K1: OTM for 3 days; K2: OTM for 7 days; K3: OTM for 14 days; KP1: OTM and CAPE for 3 days; KP2: OTM and CAPE for 7 days; and KP3: OTM and CAPE for 14 days. A nickel titanium closed coil spring 8.0 mm long with 10 g/mm 2 was installed between the upper left first molar and upper central incisor to move molar mesially. CAPE provision with a dose of 20 mg/kg bw of animal studies was done per orally. Immunohistochemistry was done to examine MMP-9 expression and osteoclast number in compression side as well as FGF-2 expression and osteoblast number in tensile side of the OTM. Statistical Analysis One-way analysis of variance test and Tukey’s honest significant difference test were performed to determine the difference between the groups ( p < 0.05). Results MMP-9 expression and osteoclast numbers in the compression side were significantly different between the groups. Similarly, FGF-2 expression and osteoclast numbers in the tensile side were significantly different between the groups. Conclusions CAPE provision during OTM increases the number of osteoblasts and the FGF-2 expression significantly in the tensile side. Osteoclast numbers and MMP-9 expression significantly decrease in the compression side.

On radial, circumferential, and spiral cracks in fractured glass plates

AbstractThis is a fractographic case study of a mechanically loaded glass plate that formed a remarkable spiral crack when the plate fractured. Common radial and circumferential cracking in disks and plates in general are first reviewed. The exceptional spiral crack is then analyzed. The origin of failure was an unusual flaw on the nominal compression side of the plate. The complex spiral fracture pattern has been observed in other large plate glass fractures that break under blunt impact conditions. Spiral cracks can form and propagate from flaws on the front side of a flexed plate that is rigidly supported at its rim or, alternatively, is supported from underneath and has a large overhang.

Gene expression and phosphorylation of ERK and AKT are regulated depending on mechanical force and cell confluence in murine cementoblasts

Cementoblasts, located on the tooth root surface covered with cementum, are considered to have tooth protecting abilities. They prevent tissue damage and secure teeth anchorage inside the periodontal ligament during mechanical stress. However, the involvement of cementoblasts in mechanical compression induced periodontal remodeling needs to be identified and better understood.Here, we investigated the effect of static compressive stimulation, simulating the compression side of orthodontic force and cell confluence on a murine cementoblast cell line (OC/CM). The influence of cell confluence in cementoblast cells was analyzed by MTS assay and immunostaining. Furthermore, mRNA and protein expression were investigated by real-time RT-PCR and western blotting at different confluence grades and after mechanical stimulation.We observed that cementoblast cell proliferation increases with increasing confluence grades, while cell viability decreases in parallel. Gene expression of remodeling markers is regulated by compressive force. In addition, cementoblast confluence plays a crucial role in this regulation. Confluent cementoblasts show a significantly higher basal expression of Bsp, Osterix, Alpl, Vegfa, Mmp9, Tlr2 and Tlr4 compared to sub-confluent cells. After compressive force of 48 h at 60% confluence, an upregulation of Bsp, Osterix, Alpl, Vegf and Mmp9 is observed. In contrast, at high confluence, all analyzed genes were downregulated through mechanical stress. We also proved a regulation of ERK, phospho-ERK and phospho-AKT dependent on compressive force. In summary, our findings provide evidence that cementoblast physiology and metabolism is highly regulated in a cell confluence-dependent manner and by mechanical stimulation.

Damage evolution mechanism of buried pipeline crossing reverse fault

Fault caused by earthquake is harmful to buried pipelines. Long-distance transportation pipelines will inevitably cross the seismic fault zones. In this paper, a numerical simulation model of X80 pipeline under reverse faulting with a crossing angle of 60° was established. Damage evolution mechanism of buried steel pipeline was analyzed. Effects of internal pressure and diameter-thickness ratio on the stress, strain and displacement of pipeline were discussed. The results show that the buckling phenomenon is more severe in the hanging wall than that in the footwall for reverse fault. For non-pressure pipeline, local collapse occurs on the compression side. When the pipeline wall buckles, the axial stress is released, and high-stress is mainly concentrated on the collapsed position. For pressure pipeline, the internal pressure aggravates the buckling degree. Then, wrinkles appear on the compression side. The results can provide a reference for anti-seismic construction, repair and maintenance of buried pipeline.

Experimental Analysis of Bending Stiffness Characteristics of Grouted Double Mortise‐Tenon Joint for Prefabricated Metro Station Structure

The grouted mortise‐tenon joint, invented as the connection between the large prefabricated components, is the key to the prefabricated underground structures, and the double‐tenon joint is most widely used in the prefabricated metro station structure. This paper conducts characteristic analysis of bending stiffness with a 1 : 1 prototype test in key working direction of different joint types for grouted double mortise‐tenon joint. The results show that the double‐tenon joint is characteristic of variable stiffness under different loads. Change laws of double‐tenon joint bending stiffness without and with auxiliary pretightening device in tension side and compression side are also discussed. The correlations for calculating double‐tenon joint bending stiffness with various axial loads and bending moments are derived at last, which offers the theory foreshadowing of similar joints.

The effect of bifidobacterium probiotic on heat shock protein-70 expression and osteoclast number during orthodontic tooth movement in rats (Rattus novergicus)

Heat shock protein (HSP)-70 expressed in the fibroblast of periodontal ligament after orthodontic tooth movement (OTM) was applied. Bifidobacterium probiotics regulate the number of osteoclasts through controlling the inflammation via Nuclear Factor Kappa Beta (NFKB) and increased cytoprotection by HSP induction. This study aimed to examine the effect of Bifidobacterium probiotic on HSP-70 expression and osteoclast number during OTM in the compression side of Wistar rats (Rattus novergicus). This research was a true experimental study which used post-test only group design. 42-healthy-Wistar rats (R. novergicus) were blind randomly divided into 6 groups; K1: OTM for 3 days; K2: OTM for 7 days; K3: OTM for 14 days; KP1: OTM and administration of Bifidobacterium probiotic for 3 days; KP2: OTM and administration of Bifidobacterium probiotic for 7 days; KP3: OTM and administration of Bifidobacterium probiotic for 14 days. OTM model was made by installed closed-coil spring with 10g/mm2 force. Bifidobacterium probiotic was orally administered with 10mL/day by means of oral gavage at 1.5 x 108 CFU/mL dose every day. Immunohistochemical analyses were performed in all study groups. One-way ANOVA and LSD test (p<0.05) were performed to compare between groups. The highest HSP-70 expression was discovered in K3 control group and the greatest osteoclast number was found in KP1 control group. The lowest HSP-70 expression and osteoclast number were found in KP3 group with significant between groups. Bifidobacterium probiotic decreased the expression of HSP-70 and osteoclast number during the orthodontic tooth movement in 14 days in the compression side.

Performance of simply supported concrete beams reinforced with high-strength polymer re-bars under blast-induced impulsive loading

A finite element model is developed in ABAQUS/CAE to simulate the dynamic response of the reinforced concrete (RC) beam under close-in air-blast loading. The model is subjected to different blast pressures at different scaled distances in free air. The values of the blast pressure have been taken from the blast tests conducted on four RC beams of size 1,700 mm × 150 mm × 150 mm by the State Key Laboratory of Explosion Science and Technology (China). The finite element predictions and available test results, including maximum mid-span displacements and damage to the beams, are presented and contrasted. The validated ABAQUS/CAE model is used to investigate the behaviour of the beams with replacement of the mild steel re-bars by the polymer re-bars of equivalent tensile strength on both compression and tension sides of the beam under air-blast loading.

Effective modeling of spiral wound gasket with graphite filler in gasketed flange joint subjected to bending loads

Abstract The flange joints with gasket are used in automobile, aircraft, pressure vessel and pipelines. The gasket deformation behavior controls the leakage phenomenon of the joint. The stress in spiral wound gasket with graphite filler is analyzed using micromechanical approach and axisymmetric finite element analysis. The material characteristics of individual constituents in gasket are modeled using their elasto-plastic behavior. The uniaxial compressive behavior of gasket is observed to be in good agreement with experimental values. The flange joint is analyzed for leakage by using 3D finite element model with individual constituents of gasket. A realistic distribution of contact stress in gasket is obtained using micromechanical approach. The contact stress distribution in the compression and tension side, when subjected to external bending load is also evaluated. The effective gasket width for sealing is contributed by filler tape alone, rather than combination of metal and filler tape in spiral wound gasket.