Nonlinear dynamic responses of shell structures using vector form intrinsic finite element method

In this paper, in order to compute nonlinear dynamic responses of shell structures, formulations of the internal forces of the shell element in vector form intrinsic finite element (VFIFE) method are developed. This novel shell element is named by VFIFE-DKT element. These elements are to compute internal forces from the deformations and the motion of the shell structures. The VFIFE method is a particle-based method. They have three key VFIFE processes such as the point value description, path element and convected material frame. Thus, the shell structure is represented by finite particles. Each particle is subjected to the external forces and internal forces. The particle satisfies the Newton’s Law. A fictitious reversed rigid body motion is used to remove the rigid body motion from the deformations of the element. The internal forces of the element in deformation coordinates satify the equilibrium equations. Through the numerical examples of the benchmark structures undergo extermly-large displacements, rotation and motion, the proposed procedures using the novel element demonstrates its accuracy and efficiency

Numerical Simulations of the Bond Stress-Slip Effect of Reinforced Concrete on the Pushover Behavior of Wall

Structure failure often occurs in the structure of wall. This failure can adversely affect the comfort level of the structure. Knowing the behavior of structure resulting from the load is important, as it can help to predict the strength of the structure and comfort of the structure being worked on. One way to find out and predict the strength and comfort of the structure as a result of the load received is experimental test and simulation. The simulation VecTor2 used to predict the shear force, crack, and displacement of reinforced concrete wall when applied the load. This simulation considered the effect of bond stress-slip effect of behavior reinforced concrete. Bonds stress-slip gives a great influence on the strength and hysteretic response of the reinforced concrete wall. That is why this study considers the influence of bond stress-slip on reinforced concrete wall. All the result of simulation VecTor2 using bond stress-slip effect would be compared with the result of the experimental test to see the accuracy of the simulation test

Numerical simulations of the bond stress-slip effect of reinforced concrete on the push over behavior of interior beam-column joint

Structure failure often occurs in the joint. This failure can adversely affect the comfort level of the structure. Knowing the behavior of interior beamcolumn joint structure resulting from the load is important, as it can help to predict the strength of the structure interior beam-column joint and comfort of the structure being worked on. One way to find out and predict the strength and comfort of the structure interior beam-column joint as a result of the load received is the experimental test and simulation. The simulation VecTor2 used to predict the shear force, crack, and displacement of the reinforced concrete column when applied the shear force. This simulation considered the effect of the bond stressslip effect of behavior reinforced concrete. Bonds stress-slip gives a great influence on the strength and hysteretic response of the reinforced concrete beamcolumn joint. That is why this study considers the influence of the bond stress-slip on a reinforced concrete column. All the result of simulation VecTor2 using bond stress-slip effect would be compared with the result of the experimental test to see the behavior and accuracy of the simulation test

A probabilistic evaluation of pier-scour potential in the Gaoping River Basin of Taiwan

A probabilistic approach is used to create a preliminary inspection evaluation form (PIEF) for scour potential at bridge sites. In Taiwan, the risk of pier scour is often evaluated using a two-step procedure. First, a bridge is visually inspected based on a PIEF. An advanced scour risk analysis is conducted for a bridge with a high PIEF score. Because a PIEF can quickly evaluate scour potential, it can be used to build a maintenance sequence for a group of bridges. However, a PIEF is often created based on only engineers’ experience; the accuracy and reliability of PIEFs have not been examined systematically. Thus, a probabilistic-based PIEF is constructed by establishing a close correlation between the PIEF score and scour potential via Taguchi method. The scour potential is evaluated by Bayesian network (BN) that incorporates experts’ judgments and results of reliability analyses. For example, the conditional probabilities (CP) in the proposed BN are calculated based on an existing PIEF and results of a stability-based reliability analysis. Thus, the proposed PIEF implicitly considers the probabilistic characteristics in the scour potential, which will provide an efficient and accurate evaluation of scour potential and assist in establishing maintenance priorities of existing bridges in Taiwan

Numerical static-load test and earthquake simulation of a cable stayed bridge

A bridge is an essential component of transportation networks and plays a crucial role in the operation of infrastructure, so maintaining this structure to guarantee the regular operation of bridges in a healthy condition is needed. The establishment of a bridge model numerically is a critical step of the bridge evaluation because many cases of the bridge test can be done numerically. The generated results can then be verified and adjusted with the real or full-scale test. This research aims to establish a numerical model of a cable-stayed bridge and perform numerical bridge tests and earthquake simulations. The targeted bridge is located in Taiwan, and it consists of four spans with three pylons. Static load tests are performed using a truck load set applied at each mid-span. Bridge displacement due to the truckloads is the primary concern of the static load test. Besides, dynamic bridge simulation under earthquake excitation is also simulated. On 18 September 2022, a destructive earthquake of moment magnitude (Mw) 7.1 occurred in Taitung County, southeastern Taiwan. Some infrastructures like bridges and buildings were damaged and even collapsed due to this earthquake. The bridge is simulated using the earthquake history record of the earthquake. The bridge's dynamical system properties are first outputted to see the bridge's natural frequencies and mode shapes. Displacement and stress history responses due to the earthquake excitation at some critical points are also evaluated. The simulation results can be a reference for real bridge testing

Functional Bearing Model (FBM) Analysis Under The Design Spectra Of Near Fault Ground Motions

Functional Bearing Model (FBM) adalah konsep penginterpretasian rubber bearing sistem yang biasanya diasumsikan sebagai satu link yang terdiri dari beberapa parameter penyusun device tersebut menjadi 3 link berdasarkan fungsi masing-masing parameter. Tiga link tersebut merupakan representasi dari Friction Element pada interface bagian atas, Rubber Element, dan Friction Element pada interface bagian bawah. Penelitian mengenai prototip jembatan yang telah diskala menyesuaikan dengan ukuran shaking table test dibebani dengan seismic loading test dari Chi-Chi Earthquakes yang telah direkam pada stasiun gempa TCU068, TCU102, dan TCU052. Dengan konsep FBM dapat terbukti bahwa setiap komponen penyusun dari rubber bearing system dapat diketahui secara terpisah. Tujuan dari penelitian ini yaitu: untuk mengetahui pengaruh dari variasi koefisien friksi yang diaplikasikan pada interface atas dan bawah rubber bearing system, untuk mengetahui parmeter-parameter apa saja untuk mendesain rubber bearing yang tepat untuk tipe jembatan dengan gempa tertentu, untuk mengetahui berapa jarak gap yang perlu disediakan untuk menghindari tubrukan antar deck pada saat gempa terjadi, dan terakhir untuk mengetahui ukuran dudukan jembatan yang perlu disediakan untuk menghindari slip pada jembatan pada saat gempa terjadi

Vpr Targets TET2 for Degradation by CRL4 VprBP E3 Ligase to Sustain IL-6 Expression and Enhance HIV-1 Replication

HIV-1 expresses several accessory proteins to counteract host anti-viral restriction factors to facilitate viral replication and disease progression. One such protein, Vpr, has been implicated in affecting multiple cellular processes, but its mechanism remains elusive. Here we report that Vpr targets TET2 for polyubiquitylation by the VprBP-DDB1-CUL4-ROC1 E3 ligase and subsequent degradation. Genetic inactivation or Vpr-mediated degradation of TET2 enhances HIV-1 replication and substantially sustains expression of the pro-inflammatory cytokine interleukin-6 (IL-6). This process correlates with reduced recruitment of histone deacetylase 1 and 2 to the IL-6 promoter, thus enhancing its histone H3 acetylation level during resolution phase. Blocking IL-6 signaling reduced the ability of Vpr to enhance HIV-1 replication. We conclude that HIV-1 Vpr degrades TET2 to sustain IL-6 expression to enhance viral replication and disease progression. These results suggest that disrupting the Vpr-TET2-IL6 axis may prove clinically beneficial to reduce both viral replication and inflammation during HIV-1 infection. HIV-1 Vpr protein counteracts host anti-viral restriction factors to facilitate viral replication and disease progression. Lv et al. demonstrate that Vpr promotes degradation of TET DNA dioxygenases. TET2 deletion or depletion enhances HIV-1 replication and sustains pro-inflammatory cytokine IL-6, while blocking IL-6 reduces Vpr's ability to enhance HIV-1 replication. © 2018 Elsevier Inc

Impact of glycemic control on circulating endothelial progenitor cells and arterial stiffness in patients with type 2 diabetes mellitus

<p>Abstract</p> <p>Background</p> <p>Patients with type 2 diabetes mellitus (DM) have increased risk of endothelial dysfunction and arterial stiffness. Levels of circulating endothelial progenitor cells (EPCs) are also reduced in hyperglycemic states. However, the relationships between glycemic control, levels of EPCs and arterial stiffness are unknown.</p> <p>Methods</p> <p>We measured circulating EPCs and brachial-ankle pulse wave velocity (baPWV) in 234 patients with type 2 DM and compared them with 121 age- and sex-matched controls.</p> <p>Results</p> <p>Patients with DM had significantly lower circulating Log CD34/KDR⁺and Log CD133/KDR⁺EPC counts, and higher Log baPWV compared with controls (all <it>P < 0.05</it>). Among those 120/234 (51%) of DM patients with satisfactory glycemic control (defined by Hemoglobin A1c, HbA1c < 6.5%), they had significantly higher circulating Log CD34/KDR⁺and Log CD133/KDR⁺EPC counts, and lower Log baPWV compared with patients with poor glycemic control (all <it>P < 0.05)</it>. The circulating levels of Log CD34/KDR⁺EPC (r = -0.46, <it>P < 0.001</it>) and Log CD133/KDR⁺EPC counts (r = -0.45, <it>P < 0.001</it>) were negatively correlated with Log baPWV. Whilst the level of HbA1c positively correlated with Log baPWV (r = 0.20, <it>P < 0.05</it>) and negatively correlated with circulating levels of Log CD34/KDR⁺EPC (r = -0.40, <it>P < 0.001</it>) and Log CD133/KDR⁺EPC (r = -0.41, <it>P < 0.001</it>). Multivariate analysis revealed that HbA1c, Log CD34/KDR⁺and Log CD133/KDR⁺EPC counts were independent predictors of Log baPWV (<it>P < 0.05</it>).</p> <p>Conclusions</p> <p>In patients with type 2 DM, the level of circulating EPCs and arterial stiffness were closely related to their glycemic control. Furthermore, DM patients with satisfactory glycemic control had higher levels of circulating EPCs and were associated with lower arterial stiffness.</p

Eccentric muscle challenge shows osteopontin polymorphism modulation of muscle damage.

A promoter polymorphism of the osteopontin (OPN) gene (rs28357094) has been associated with multiple inflammatory states, severity of Duchenne muscular dystrophy (DMD) and muscle size in healthy young adults. We sought to define the mechanism of action of the polymorphism, using allele-specific in vitroreporter assays in muscle cells, and a genotype-stratified intervention in healthy controls. In vitro reporter constructs showed the G allele to respond to estrogen treatment, whereas the T allele showed no transcriptional response. Young adult volunteers (n = 187) were enrolled into a baseline study, and subjects with specific rs28357094 genotypes enrolled into an eccentric muscle challenge intervention [n = 3 TT; n = 3 GG/GT (dominant inheritance model)]. Female volunteers carrying the G allele showed significantly greater inflammation and increased muscle volume change as determined by magnetic resonance imaging T1- and T2-weighted images after eccentric challenge, as well as greater decrement in biceps muscle force. Our data suggest a model where the G allele enables enhanced activities of upstream enhancer elements due to loss of Sp1 binding at the polymorphic site. This results in significantly greater expression of the pro-inflammatory OPN cytokine during tissue remodeling in response to challenge in G allele carriers, promoting muscle hypertrophy in normal females, but increased damage in DMD patients