bluuebunny/crossref_metadata_2025 huggingface dataset:
La thrombose au cours des néoplasies myéloprolifératives
Authors: Guy Alexandre , James Chloé
Published: September 2019

Les néoplasies myéloprolifératives (NMP) sans translocation de Philadelphie sont des maladies hématologiques acquises caractérisées par la prolifération d’une ou plusieurs lignées sanguines. Elles regroupent la polyglobulie de Vaquez (PV), la thrombocytémie essentielle (TE) et la myélofibrose primitive (MFP). La survenue de thromboses artérielles ou veineuses est un risque majeur au cours de ces maladies. Les facteurs de risque reconnus actuellement sont un âge supérieur à 60 ans et un antécédent de thrombose. Les mécanismes concourant à ce risque pro-thrombotique augmenté sont cependant multiples et complexes, impliquant l’ensemble des cellules sanguines, des facteurs plasmatiques et le compartiment endothélial. Ces dernières années, de nouveaux mécanismes physiopathologiques ont été révélés.
Comparison of the Subjective Elbow Value with the DASH, MEPS und Morrey Score after Olecranon Fractures
Authors: Gathen Martin , Ploeger Milena Maria , Peez Christian , Weinhold Leonie , Schmid Matthias , Wirtz Dieter Christian , Burger Christof , Kabir Koroush
Published: September 2019

Background Olecranon fractures are common injuries that can occur in patients of any age. To assess the postoperative outcome, multiple scoring systems like the DASH, MEPS und Morrey Score have been described. The goal of this paper is to compare the subjective elbow value (SEV) to these commonly used scoring systems. We hypothesized that the SEV would have a high correlation and practicability for the evaluation of elbow function after isolated olecranon injury.

Patients and Methods Clinical data of 40 patients were collected and retrospectively analysed. All patients suffered an isolated olecranon fracture and were surgically treated by tension band wiring or plate fixation. In the follow-up examinations the Mayo Score, DASH Score, Morrey Score and SEV were measured for correlation purposes.

Results The mean follow-up time was 70.5 ± 45.6 months. The median DASH Score was 9.9 (4.1 – 20.4) and 100 (85 – 100) for the MEPS. The median Morrey Score was 98 (92 – 100). The median SEV was 90% (80 – 95%). The Pearson correlation between the DASH and SEV was −0.85 and 0.80 between the MEPS and the SEV.

Conclusions The SEV shows a high correlation to the most commonly used scoring systems for outcome evaluation after elbow injury. It is easy to use and can be seen as a valuable tool to assess patients after olecranon fractures.
Selective Carpus Denervation – One of Treatment Options of Madelung Deformity
Authors: Pilny Jaroslav , Slodicka Roman , Hajek Petr , Horackova Katerina
Published: September 2019

Case presentation of 7 years follow up of female patient with wrist arthritis caused by Madelung deformity. As causal treatment remains unknown, the pain reduction by means of selective wrist denervation is one possible option.
Dysphagie bei tracheotomierten Patienten nach Langzeitbeatmung
Authors: Heidler M.-D.
Published: September 2019

Unabhängig von der Art der kritischen Erkrankung haben tracheotomierte Patienten ein hohes Risiko für die Entwicklung einer Schluckstörung. Diese ist potenziell lebensbedrohlich, da sie zu Aspiration und Pneumonie führen kann. Vor einer oralen Nahrungsgabe sollte daher unbedingt eine Schluckdiagnostik mittels Bolusfärbetest und/oder FEES durchgeführt werden. Da ein physiologischer Luftstrom durch den Larynx und ein adäquater subglottischer Druck Schlüsselkomponenten eines effektiven Schluckaktes sind, sollte eine Oralisierung bei geblockter Trachealkanüle möglichst vermieden werden.
Effects of Two Modalities of Whole-body Electrostimulation Programs and Resistance Circuit Training on Strength and Power
Authors: DʼOttavio Stefano , Briotti Gianluca , Rosazza Cristina , Partipilo Filippo , Silvestri Adriano , Calabrese Cosimo , Bernardini Andrea , Gabrielli Paolo Roberto , Ruscello Bruno
Published: September 2019

The main purpose of this study was to compare the effects on strength and muscle power of a training program based on two different modalities of whole-body electrostimulation (WB-EMS) with respect to a resistance-training program aimed at improving dynamic strength. Twenty-two subjects participated in this study: Thirteen male (age 25.2±2.8 years; height 1.78±0.1 m; body mass 72.8±6.4 kg; body fat 11.6±2.3%) and nine female (age 28.2±3.5 years; height 1.63±0.05 m; body mass 56.8±7.6 kg; body fat 19.1±4.7%). Participants were randomly assigned to three groups that underwent three different 6-week training programs: two modalities of WB-EMS, based on different electrical parameters (experimental), and circuit training with overloads (control). Force-velocity curves were calculated for each participant before and after treatment. All groups improved their level of strength and muscle power (paired sample t-Test, p<0.01; d>1) with a similar magnitude. No significant differences were observed between groups (two-way 2×3 Anova, p>0.05) at the end of the experimentation. This study suggests that WB-EMS might be considered as a valid and faster alternative – or an important complementary procedure – to a traditional overload-based resistance-training program for the development of the DS.
Dynamic Scoliosis Correction as Alternative Treatment for Patients with Adolescent Idiopathic Scoliosis: a Non-Fusion Surgical Technique
Authors: Trobisch Per David , Kobbe Philipp , Baroncini Alice
Published: September 2019

Anterior dynamic scoliosis correction is an innovative non-fusion option in the treatment of patients with severe adolescent scoliosis. Growth modulation and sometimes intraoperative curve correction is achieved by convex insertion of segmental screws and a flexible polyethylene cord. The present review analyses and discusses the current literature and proposes a new treatment algorithm that is based on our own experience. Short term results are published for approximately 100 patients from different institutions. Fusion could be prevented in the vast majority of patients. Perioperative complication rate is very low but a few cases of cord rupture and overcorrection are reported. Anterior dynamic scoliosis correction has promising short term results but there is a paucity of literature and optimal criteria for the best candidate has yet to be defined.
Advanced Surgical Trauma Care Course – Evaluation of a Fracture Simulation Course Concept with Intact Soft Tissue
Authors: Wegmann Kilian , Rausch Valentin , Burkhart Klaus Josef , Hackl Michael , Leschinger Tim , Müller Lars
Published: September 2019

Purpose Currently, surgical training in the clinical scenario is limited by duty-hour restrictions as well as an increasing specialization within the numerous surgical fields. In such an environment, surgical training in subspecialties becomes both, more important and challenging. Against this background, purpose of the present study was to evaluate a new course format for advanced training in fracture treatment. In the studied course format, cadaveric wrist or elbow specimens with prefabricated fractures were used with the aim of improving the learning effect for the attendees. On these specimens, operative treatment with specific osteosynthetic implants was performed under radiographic control. We hypothesized that simulation in a complex scenario such as the one used in the studied course format leads to a subjectively better learning effect regardless of prior surgical experience.

Methods 205 participants in 16 courses between 2016 and 2018 were surveyed regarding their operative experience, previously attendances of trauma care trainings and subjective learning effect in the surveyed course and the trainings attended previously. Based on a ten-step scale, results in the subjective learning effect were compared between the investigated course and other trainings and to the individual operative experience.

Results The learning effect of the surveyed fracture courses was assessed with a median of 9/10 for the theoretical part and 10/10 for the practical part, significantly better than in trainings attended previously. The surveyed participants reported that they each performed 308 operations per year on average. Other course formats were attended significantly more frequent than courses on prefractured human specimens. The respondents reported a subjectively higher learning effect of the evaluated course concept in comparison to previously attended courses in practical and theoretical aspects.

Conclusions The reported innovative course format is an efficient concept for education in surgical trauma care, suited for more novice and advanced surgeons.
Patient Expectations about Communication in the Perioperative Setting of Elective Knee Surgery – a Questionnaire-based Cross-sectional Study
Authors: Walter Sebastian G. , Naal Florian , Impellizzeri Franco M. , Moser Berthold , Schildberg Frank A. , Drobny Tomas , Preiss Stefan , Salzmann Gian M.
Published: September 2019

Background Patient expectations are an issue which is attracting increased interest in outcome research for knee surgery procedures. So far, research into patient expectations has mainly focused on the procedure and postoperative functional improvements. The purpose of this study was to identify patient expectations in the perioperative setting.

Material and Methods This was a single-center prospective study. A 17-item questionnaire (ordinal answer scale) about patientsʼ perioperative expectations was developed and completed by patients undergoing elective joint-preserving knee surgery. The study covered a period of 3 months and included all patients consecutively undergoing knee surgery. Subgroup analysis was performed for gender, age and type of insurance.

Results 111 consecutive patients completed the questionnaire on admission. Significant preferences for one answer option were found for 13 out of 17 items. Patients considered it “unimportant” whether or not the physician wore a white coat during the consultation and “very important” that the first medical consultation after the patient was discharged from hospital was with the surgeon who had performed their operation. A concise explanation of the surgical procedure using images, talking to the surgeon the day before surgery and immediately after surgery, having their wound personally inspected by the surgeon, and, finally, the availability of the surgeon by phone were regarded as “important”. There were no differences in patient responses between the different subgroups.

Conclusion Patients expect a high personal commitment and availability of the surgeon during the entire perioperative setting, starting from the first consultation and continuing during follow-up examinations.
Trithioorthoester Exchange and Metathesis: New Tools for Dynamic Covalent Chemistry
Authors: Bothe Michael , Orrillo A. Gastón , Furlan Ricardo L. E. , von Delius Max
Published: September 2019

To expand the toolbox of dynamic covalent and systems chemistry, we investigated the acid-catalyzed exchange reaction of trithioorthoesters with thiols. We found that trithioorthoester exchange occurs readily in various solvents in the presence of stoichiometric amounts of strong Brønsted acids or catalytic amounts of certain Lewis acids. The scope of the exchange reaction was explored with various substrates, and conditions were identified that permit clean metathesis reactions between two different trithioorthoesters. One distinct advantage of S,S,S-orthoester exchange over O,O,O-orthoester exchange is that the exchange reaction can kinetically outcompete hydrolysis, thereby making the process less sensitive to residual moisture. We expect that the relatively high stability of the products might be beneficial in future supramolecular receptors or porous materials.
Neurosurgical Infections
Authors: Sader Elie , Moore Justin , Cervantes-Arslanian Anna M.
Published: September 2019

Patients in the neurointensive care unit often undergo life-saving neurosurgical interventions that can be associated with serious complications. Infection is a common and sometimes fatal complication of such procedures. Infection may occur not only in the setting of major cranial and spinal surgery, but also with common minor procedures that utilize neurosurgical devices, such as placement of external ventricular drains, ventriculoperitoneal shunts, and deep brain stimulators. In this article, we review the epidemiology and microbiology of these infections, and discuss their general and procedure-specific risk factors and treatment options.
Sydenham's Chorea; Clinical and Magnetic Resonance Imaging Findings, a Retrospective Observational Study in Children
Authors: Hanci Fatma , Hizal Mustafa , Türay Sevim , Kalaycioğlu Oya , Kabakuş Nimet
Published: September 2019

The purpose of this study was to evaluate the correlation between magnetic resonance imaging (MRI) findings and demographic and clinical characteristics, response to treatment times, and recurrence rates of Sydenham's chorea (SC), the most common of the acquired pediatric choreas. The clinical and radiological findings of 12 patients presenting to the pediatric neurology clinic in the previous 4 years and diagnosed with SC on the basis of the modified Jones criteria were investigated retrospectively from the hospital files. In addition, we measured the maximum prefrontal cortex and basal ganglia (globus pallidus, putamen, and caudate nucleus) thicknesses in the axial plane from patients' cerebral MRIs and compared these values with prefrontal cortex and basal ganglia thicknesses of a healthy control group measured using the same technique. Patient and control groups' cranial and basal ganglia MRIs were found to be normal. However, patients' globus pallidus thicknesses were significantly lower than those of the healthy control group. Additionally, the globus pallidus values of patients with recurrent SC and a prolonged healing time were lower than average. However, we determined no significant difference in terms of prefrontal motor cortex, caudate nucleus, or putamen thicknesses between the patient and control groups. Low globus pallidus thicknesses in patients with SC may indicate atrophy associated with globus pallidus involvement. Further experimental and prospective and long-term studies are needed for a better understanding of the factors affecting the pathophysiology, recurrence, and healing time of SC.
Effects of aluminum doping upon properties of cadmium sulfide thin films and its effect on ITO/CdS:Al/NiOx/Ni/Au diodes
Authors: Chavez-Urbiola I. R. , Pintor-Monroy M. I. , Willars-Rodriguez F. J. , Vorobiev Y. V. , Ramírez-Bon R. , Quevedo-Lopéz M. A.
Published: September 2019

We analyze the Al doping effect in CdS films by chemical bath deposition and how it impacts this doping effect in a heterojunction, for the case of ITO/CdS:Al/NiOx/Ni/Au. The results show that the doping effect of aluminum on the CdS films by chemical bath deposition does slightly affect the structural and morphological properties. The impact of the doping is related to the electrical properties; first, with a decrement in the resistivity from 108 to 107 Ω cm, the work function decreases from 4.7 to 4.3 eV, the bandgap and the valence band suffers a small increment of 0.1 eV. The change in the electrical properties impacts the diode behavior, and the increment in the work function leads to an increment of the Fermi energy level difference between NiOx and CdS:Al; this difference was reflected in a wider depletion region and a reduction of the leakage current.
Karpman-Washimi magnetization in relativistic quantum plasmas
Authors: Jamil M. , Rasheed A. , Usman M. , Arshad W. , Jawwad Saif M. , Jung Young-Dae
Published: September 2019

An interesting phenomenon of ponderomotive Karpman-Washimi magnetization is investigated in ultrarelativistic degenerate plasmas. The quantum characteristics of plasma electrons are considered on incorporating the Fermi pressure and exchange-correlation potential terms into the fluid model of plasmas. The ion fluid is referred to as classically warm. The Karpman-Washimi ponderomotive magnetization MK−WStr and radiation power P¯K−WStr are derived as functions of scaled wave number k¯, scaled effective frequency ω¯∗, ratio of thermal temperature of ions to the Fermi temperature of electrons E¯i′, and fine structure constant α for two cases of streaming and nonstreaming quantum plasmas. It has been observed that the Karpman-Washimi ponderomotive magnetization MK−WStr and the Karpman-Washimi radiation power P¯K−WStr are significantly affected by the scaled streaming velocity v¯0.
Orientation-specific switching of inelastic electron tunneling in an oxygen–pyridine complex adsorbed onto an Ag(110) surface
Authors: Jang Sanghoon , Shin Taeho , Abbas Hafiz Ghulam , Hahn Jae R. , Kang Hong Seok
Published: September 2019

Here, we report the development of a molecular rotary switch (a “stator–rotor” consisting of a single oxygen molecule as a stator and a single pyridine molecule as a rotor) on a silver surface. The pyridine molecule was bonded to the oxygen molecule and was found to rotate to enable “ON” or “OFF” vibrational conductance through the oxygen molecule. Four stable sites around the oxygen molecule were observed, and vibration conductance turned on and off depending on the site at which the pyridine molecule bonded. The spatially resolved mapping of the vibrational change revealed two locations of maximal vibration intensity, separated by ∼3 Å. These positions acted as two conducting channels. The two distinct vibrational energy levels were associated with the switching process. Adsorption-induced electron transfer between the silver layers and the molecules enhanced the local interactions between the molecules. The two vibration modes were excited by resonant tunneling despite substantial interactions between the molecules, which resulted in a decrease in tunneling conductance. An independent pathway exists for the vibrational excitation process by tunneling electrons and intermolecular interactions.
Enhanced thermoelectric properties in chimney ladder structured Mn(BxSi1-x)1.75 due to the dual lattice occupation of boron
Authors: Xu Xiao , Xie Lin , Lou Qing , He Mingkai , Jiang BinBin , Yu Yong , Wu Di , He Jiaqing
Published: September 2019

Due to its abundant, inexpensive, and nontoxic features, higher manganese silicide MnSi1.75 has drawn intensive attention as a promising middle temperature thermoelectric material. In this study, we applied aberration-corrected scanning transmission electron microscopy to characterize its chimney ladder crystal structure and found the particular contrast along the [110] direction, contributed from the enhancement of helical Si layers on Mn layers. Moreover, it is demonstrated that the Seebeck coefficient and electrical conductivity of MnSi1.75 could be simultaneously reinforced via boron doping, giving a peak power factor value of 1.72 mW m−1 K−2 at 723 K for Mn(B0.04Si0.96)1.75. Interestingly, it is indicated that boron would occupy both Si lattice and interstitial sites, resulting in an optimized charge carrier concentration and a reduced lattice thermal conductivity at the same time. A maximum zT value of ∼0.55 at 773 K and a high zTave value of 0.4 from 300 to 823 K were eventually realized in the Mn(B0.04Si0.96)1.75 sample.
Fast electron paramagnetic resonance magic angle spinning simulations using analytical powder averaging techniques
Authors: Saliba Edward P. , Barnes Alexander B.
Published: September 2019

Simulations describing the spin physics underpinning nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy play an important role in the design of new experiments. When experiments are performed in the solid state, samples are commonly composed of powders or glasses, with molecules oriented at a large number of angles with respect to the laboratory frame. These powder angles must be represented in simulations to account for anisotropic interactions. Numerical techniques are typically used to accurately compute such powder averages. A large number of Euler angles are usually required, leading to lengthy simulation times. This is particularly true in broad spectra, such as those observed in EPR. The combination of the traditionally separate techniques of EPR and magic angle spinning (MAS) NMR could play an important role in future electron detected experiments, combined with dynamic nuclear polarization, which will allow for exceptional detection sensitivity of NMR spin coherences. Here, we present a method of reducing the required number of Euler angles in magnetic resonance simulations by analytically performing the powder average over one of the Euler angles in the static and MAS cases for the TEMPO nitroxide radical in a 7 T field. In the static case, this leads to a 97.5% reduction in simulation time over the fully numerical case and reproduces the expected spinning sideband manifold when simulated with a MAS frequency of 150 kHz. This technique is applicable to more traditional NMR experiments as well, such as those involving quadrupolar nuclei or multiple dimensions.
Charge separated states of endohedral fullerene Li@C20
Authors: Yang Yi-Fan , Gromov Evgeniy V. , Cederbaum Lorenz S.
Published: September 2019

We report on high-level coupled-cluster calculations of electronic states of the neutral endohedral fullerene Li@C20. All computed states of neutral Li@C20 are found to be the charge separated states of the Li+@C20− type. Using the state-of-the-art EA-EOM-CCSD method, we found that neutral Li@C20 (D3d) possesses several valence and superatomic charge separated states with considerable electron binding energies, the strongest bound state of Li+@C20− being the 12Eu state (6.73 eV). The valence charge separated states correspond to two sets of states of C20−. The states 12Eu, 12A2u, 22Eu, and 22A2u correspond to the respective bound states of C20−, and the states 22A2g, 12Eg, 12A1g, and 42Eu correspond to the unbound states of C20−. There are eight superatomic states with electron binding energy higher than 1.0 eV, being much stronger bound than the single weakly bound superatomic state of the parent fullerene anion. The analysis of the radial density distribution of the excess electron on the carbon cage indicates the important role of the inner part of the superatomic states in forming the charge separated states.
Correction
Authors: Bhatti T.H.
Published: September 2019

Correction to a meeting abstract (pg 104a, Abstr. No. 393)
Construction of realistic hybrid computational fetal phantoms from radiological images in three gestational ages for radiation dosimetry applications
Authors: Makkia Rasha , Nelson Keith , Zaidi Habib , Dingfelder Michael
Published: September 2019

Radiation exposure and associated radiation risks are major concerns for fetal development for pregnant patients who undergo radiation therapy or diagnostic imaging procedures. In order to accurately estimate the radiation dose to the fetus and assess the uncertainty of fetal position and rotation, three hybrid computational fetus phantoms were constructed using magnetic resonance imaging (MRI) for each fetus model as a starting point to construct a complete anatomically accurate fetus, gravid uterus, and placenta. A total of 27 fetal organs were outlined from radiological images via the Velocity Treatment Planning System. The DICOM-Structure set was imported to Rhinoceros software for further reconstruction of 3D fetus phantom model sets. All fetal organ masses were compared with ICRP-89 reference data. Our fetal model series corresponds to 20, 31, and 35 weeks of pregnancy, thus covering the second and third trimester. Fetal positions and locations were carefully adapted to represent the real fetus locations inside the uterus for each trimester of pregnancy. The new series of hybrid computational fetus models together with pregnant female models can be used in evaluating fetal radiation doses in diagnostic imaging and radiotherapy procedures.
Bed Surface Grain Size Evolution under Unsteady Flow Conditions in a Degrading Channel
Authors: Li Zhijing , QiuliLi  , Jin Zhongwu , Yao Shiming , YinjunZhou
Published: September 2019

Laboratory flume experiments were conducted in order to identify the temporal evolution of bed surface grain size properties by unsteady flows under zero sediment feeding conditions. Purposely designed sediment beds were composed by well-sorted gravel and sand, for each case, detailed data of the bed surface composition were collected. It is found that for all cases, the final sediment bed in the whole reach always shows a coarsening feature, and the coarsening process is much more developed near the inlet boundary. Further, the time variation of the percents of gravel and sand are observed increase or decrease alternately during the experiment and finally close to their initial percents. Besides, the experimental results show that there is no direct correlation between the flow unsteadiness and the coarsening degree of the final bed.
Study on Processes of Changshou Waterway after 175m Experimental Impoundment of the Three Gorges Reservoir
Authors: Li Yuchen , Shang Qianqian , Jiang Ji , Da Bing , Gao Yajun
Published: September 2019

In 2008, the normal pool level in front of the Three Gorges Dam was set at 175m, and afterwards the spatial distribution of sedimentation in fluctuating backwater region changed significantly. Moreover, with the operation of Xiluodu and Xiangjiaba Reservoirs in the upstream of Yangtze River, sedimentation in fluctuating backwater area has also changed accordingly. In order to analyse the characteristics of erosion and deposition in the fluctuating backwater area under new water and sediment conditions, Changshou Waterway which located in the middle section of the fluctuating backwater region is chosen as one typical waterway, and the measured data of Changshou Waterway is then investigated. Results show that: the riverbed of the middle section in the fluctuating backwater area is changed from silting to slight scouring, there is no accumulated deposition after the experimental impoundment of the Three Gorges Reservoir, and the riverbed deformation in the Zhongshui Moraine of the Changshou Waterway is much more sensitive to water and sediment conditions while the downstream curved channel near Matou Moraine is relatively stable.
Developing a Hydrology Coupled 2D Cellular Automata Model for Efficient Urban Flood Simulation
Authors: Zhou Xing , Zhang Ruilin , Zhong Zhiyu , Guo Shenglian
Published: September 2019

To achieve fast and efficient flood modelling for urban area, a two-dimensional cellular automata based model was developed and further coupled with a hydrological model. The model was implemented in parallel environments and tested by an analytical solution and a real word case. The analytical case results showed that the model is capable of simulating water-depth under a reasonable slope threshold and grid resolution condition using only a short computational time. Slope threshold and grid resolution are the two key factors affecting the computational efficiency and model accurcay. The introduction of the state update interval significantly improved the computational efficiency. In the case of the real world example, the results were also in reasonable range.In general, this model can be applied to rapid flood analysis for large urban areas.
Study on the influence of the sediment at reservoir bottom on dynamic damage of gravity dam
Authors: Zhai Yafei , Zhang Liaojun , Bi Zhonghui , Tang Yujie
Published: September 2019

Traditional linear elastic model or elastic-plastic DP model can hardly reflect the damage and failure law of the concrete and rock foundation when the tensile and compressive strengths exceed the limitation. Therefore, the concrete damage model is used to simulate the dynamic damage of gravity dam body. According to the similarity of concrete and rock mass materials, the damage model of concrete is extended to rock mass materials. The sediment at the bottom of reservoir is simulated by viscous and high density compressible fluid. Based on this, a multi-coupling simulation model is established, which can reasonably reflect the dynamic damage evolution process of the dam concrete and dam foundation rock mass. Based on the Koyna gravity dam project, taking the thickness of sediment at the bottom of the reservoir as a variable, FEM transient analysis is carried out in this paper. By comparing the damage areas of the model, the displacement of the key points of the dam body along the river and the energy dissipation index, the influence of different thicknesses of the sediment is quantified on the damage of the multi-coupling system of the gravity dam. The calculation results obtained are close to the actual earthquake damage, which verifies the feasibility and rationality of the calculation method. The results of the analysis also show that: the seismic damage of the gravity dam can be consistently reduced with the increase of the thickness of the reservoir bottom sediment. Compared with the dam body, the change of thickness of sediment has less influence on dam foundation damage.
Research on the Influence of Pavement Roughness Level on the Driving Comfort
Authors: Wang Gui-hua , Zhou Ji-guo
Published: September 2019

The car-bridge pavement roughness level has a great influence on the vibration of the coupled system and on the driving comfort. Numerical simulation model of vehicle-bridge coupling vibration analysis is established to study the vehicle-bridge system while vehicle running on a long-span bridge. The vibration characteristics of vehicle-bridge system and the driving comfort of vehicle are studied while vehicle running on a long-span bridge under different pavement roughness level. The results show that, the vertical impact coefficient and the comfort evaluation index both gradually increase with the improving level of roughness.
Inversion of permanent deformation parameters of neural network based on bee colony optimization algorithm
Authors: Zhao Mengdie , Zhang Xianlei , Guo Lei , Li Zongkun
Published: September 2019

In this research, a method of artificial bee colony algorithm was proposed to optimize BP neural network parameters and then introduced to parameter inversion of geotechnical engineering. The method is based on the research and analysis of permanent deformation of geotechnical earthquake engineering and aimed at addressing the shortages of BP neural network which is slow to converge and may easily get minimum value. This method not only strengthens the global optimization ability of bee colony optimization algorithm, but also reflects the high accuracy of predicting nonlinear problems of BP neural network and the strong generalization ability. The proposed method also improves the prediction accuracy This new proposed method was validated by using the earthquake data of Zipingpu concrete faced rockfill dam in WenChuan earthquack. The results showed that this method can better solve the problem of permanent deformation parameters and can be extended to inversion predict of the same kind.
GDS Triaxial Test on the Reinforcement Effects of Bermudagrass Root-soil Complex
Authors: Ji Xiaolei
Published: September 2019

GDS triaxial test system was conducted to investigate the stress-strain relationship, strength characteristic and failure mechanism of Bermuda grass root-soil complex, and the effect of different root system distribution on strength of root-soil complex was also studied. The results indicate: ①the root system can improve the shear strength of soil and limit the deformation of that complex effectively. ②The contribution of the root system to the strength promotion of the root-soil complex is mainly reflected in the increase of cohesion. ③The strength increase of the root soil complex is related to the arrangement of roots in the soil. The effects are listed in the sequence as mixed placement> intersectant placement> vertical placement >horizontal placement >inclined placement. The research results provide theoretical support for the formation mechanism of the shear strength of the root-soil complex, which is meaningful to guide the selection of slope protection plants.
Research on Proper Height of the New External-shearing and Internal-framing Structure
Authors: Jianwei Cheng , Yong Wang , Qichao Peng , Qing Jiang
Published: September 2019

this study proposes a new external-shearing and internal-framing structure, and introduces the merits and application scenarios of this new structure. With a one-staircase six-house pagoda-style residential building as the study case, we tested mechanical and seismic indicators of the proposed new structure, including the floor rigidity, the shear bearing capacity, the shear-weight ratio, the floor displacement ratio and the floor displacement angle, under different degrees of seismic fortification intensity. The test result shows that the new external-shearing and nternal-framing structure has good mechanical performance when applied to pagoda-style residential buildings, the structural control indicators meet the standards and the structure can be widely used in buildings below 33 floors with a degree of seismic fortification intensity ranging from 6 to 7.
A study on the application of cage-type retaining wall in flood control
Authors: Jie Liu , Chen Yanyu , Yan Yongsheng , Geng Yehan , Zhan Wang , Li Kaixuan
Published: September 2019

Sub-embankment and geo-bag embankment had been adopted to increase the retaining height in flood control. However, these methods have taken up a lot of manpower and material resources, because of shortage of time, poor soil supplement and inconvenient construction procedures, which limited the scope of application. Cage type retaining wall has the advantages of quick and convenient installation, strong mobility, low cost and easy disassembly during the flood season. The stability of cage type retaining wall is the core issue in engineering application. In this paper, the stability of retaining wall is calculated with various lengths of geomembrane which is laid in the upstream. The results show that stability safety factors of the structure are1.28, 1.58, 1.74 and 1.9 when the lengths of geomembrane are 0.0, 0.5, 1.0 and 2.0 respectively, which could meet the engineering requirements. Besides, application notices are also discussed in this paper.
Comparative Research on Anti-Seismic Test for FPB and Ordinary Spherical bearing
Authors: Junyong XIA , Ma Baihu , Bin Du , Xu Xiangdong , Guangzhong Yu , Liu Jun
Published: September 2019

In this paper, a two-span-32m-simply supported girder bridge is studied. The Anti-seismic experiments are conducted for two groups of two-span bridges of low pier and middle pier based on a bridge model, 1/7 large of the real bridge established by principle of similitude. The impacts of three different seismic oscillations on the seismic response(displacement of bearings, internal force of piers and etc.) of simply supported beams of ordinary spherical bearings and FPBs under 7,8 and 9 intensities are discussed. The damage under different seismic oscillations are made clear and the study shows that FPBs boast of good Anti-seismic performance under near seismic oscillations of different levels and are more suitable for low pier structures.
Seismic Response Analysis of Oblique Incident Angle of SV Wave on Immersed Tunnel
Authors: He Cong , Gong Junpeng , Xu Guoyuan
Published: September 2019

On the basis of viscous-elastic artificial boundary, the ground motion input is transformed into the equivalent node load to achieve the oblique incidence of seismic waves. The two-dimensional finite element model of Nanchang Honggu immersed tunnel section is established by using finite element software. The influence of different incident angles on the dynamic response of the immersed tunnel is analyzed under the oblique incident of the SV wave. The results show that the seismic response law of the immersed tunnel is significantly different from that of the vertical incident when the SV wave is obliquely incident. The structural stress of the immersed tunnel is larger at the corner of the immersed tunnel and the junction of the intermediate partition with the floor and the roof. As the incident angle increases, the vertical response of the immersed tunnel structure increases significantly. Therefore, when seismic design analysis of the immersed tunnel is carried out, the influence of the oblique incidence of the ground motion on the dynamic response of the immersed tunnel should be considered.
Seismic perfomance of a new type prefabricated concrete frame joint
Authors: Gu Wei , Chang Zhongquan , Li Zhongpei , Zhang Yannian
Published: September 2019

In view of the problems existing in the beam-column joint of prefabricated concrete frame structure, a new hook-type joint is proposed in this paper. The quasi-static tests were repeatedly performed on full-scale models, using combined joints with different concrete strength and steel bar types. The failure pattern, carrying capacity, hysteresis loop and energy dissipation ability of the new hook-type joints were analyzed. The results show that the failure process of hook-type joint has five stages; they are initial crack, thorough crack, beam yield, limit, and failure. The hook-type joints have good working performance, good recovery characteristics and strong strength and stiffness, but the energy dissipation ability is weak.
Analysis of performance-based seismic design method for super high-rise frame-supported shear wall structure
Authors: Ling Yuhong , Li Anqi , Liu Rui
Published: September 2019

In this paper, the advanced performance-based seismic theory is introduced, and combining with the seismic codes and high-rise building codes, a performance-based seismic design approach is established for high-rise frame-supported shear wall structure. Firstly, the performance objective is determined, and then calculation under frequent earthquakes, fortification earthquake and rare earthquake is carried out, finally, the performance analysis is carried out to see whether it achieves the predetermined performance objective. Then taking a high-rise frame-supported shear wall structure as an example, based on the performance-based seismic design method, YJK and ETABS software were used to carry out the performance-based seismic design under the action of frequent earthquakes and fortification earthquakes. Next, Perform3D software was used to analyze dynamic elastic-plastic time-history analysis under the action of rare earthquakes. In addition, the analysis of transfer component performance were conducted for quantitative control of the bearing capacity and deformation of reinforced concrete structures and structural members. The calculation results show that relevant parameters can meet code requirements and the seismic performance of the whole structure and components can reach the expected performance objectives. Finally, we present a summary of the proposed seismic strengthening measures and make suggestions for the whole structures, by which the structure can meet the seismic fortification code requirements and be safe and reliable.
Experimental Study on Compression Behavior of Solidified Silt in Corrosive Site
Authors: Wu Zhiqiang , Xu Kai , Cai Zhengyin , Geng Zhizhou , Huang Yinghao
Published: September 2019

The use of cement is a common technique to improve the bearing capacity of muddy coast foundation, and the determination of compression parameter of cemented soft clay is of great importance in the design process of solidification engineering. One-dimensional consolidometer was used to measure the vertical compression of cemented clay at different cement content and curing time. Test results indicate that cemented clay formed under seawater condition is a kind of strongly-structured soil with a relatively low compressibility. Yield stress increases with cement content and curing time, while compressibility decreases with the increase of cement content and curing time. The compress deformation is rather small with less vertical load, but significant compress deformation occurs when vertical load is greater than yield stress. Statistical data show that the yield stress can be used to represent the effect of cement content and curing time on compressibility of cemented clay. And a power function relationship exists between compressibility and the yield stress within the range considered in this study.
Experimental Study on the Effect of Stray Currents on the Mechanical Properties of Concrete with Different Cementitious Systems and Rebar Corrosion
Authors: Zhou Jun-hong , Zhan Wen , Li liang , Xu Qing , Yu Yi-ming
Published: September 2019

In order to study the effect of stray current on the compressive strengths of concrete and rebar corrosion under different cementitious systems, a set of test device is designed to simulate the migration of stray current in the concrete. The compressive strength of the concrete is tested in the 4th week and 7th week after electrification to evaluate the compressive strength ratio of the concrete with different cementitious materials under the influence of stray current. The polarization curve of the rebar is measured to evaluate the electrochemical properties of the rebar. The result shows that: The influence laws of stray currents on the strength of concrete with different cementitious materials and rebar corrosion are consistent. The reduction extent of the compressive strength of concrete and corrosion extent of rabars follows the sequence: pure cement > fly ash+mineral powder+fiber>fly ash ≥ fly ash+mineral powder+swelling agent≥fly ash+mineral powder.With the increase of current time, The longer the current time is, the more significant the reduction of compressive strength is, and the more serious the rebar corrosion is.
Research on reinforcement at the RCC dam toe of a hydropower station
Authors: Yuelin Sun , Yan Zhao , Minghao Qin
Published: September 2019

The dam of a hydropower station is a RCC arch dam. Based on relevant tests and monitoring data, the compression strength of the dam concrete and the temperature of grouting of the transverse joints in some areas do not meet the design standard. To solve those quality problems, this paper evaluated the stress and deformation of the present dam and checked the safety of the dam. In addition, by analyzing the reinforcement body of the dam, the paper assessed the safety of the reinforced dam. According to the calculating results by FEM, the maximum equivalent tensile stress exceeds the allowable tensile stress and the exceeding area mainly locates on the dam heel of upstream face, which extends about 5.20 meters upward from the foundation. The effect of the reinforcement at the dam toe is obvious and the tensile stress after reinforcement meets the standard under the condition that the shear strength between the reinforcement and the dam body is not reduced or is reduced by less than 30%.
Experimental Study on the Influence Factors of Durability of Composite Geomembrane
Authors: Zhizhou Geng , Chengfeng Zheng , Kai Xu
Published: September 2019

The durability of composite geomembrane materials may decrease under the long-term influence of natural environment such as light and temperature. In order to study the influence of different factors on the durability of composite geomembrane, the durability of composite geomembrane with different aging time was tested by artificial accelerated aging test. The experimental results show that the longitudinal tensile strength of composite geomembrane material decreases slightly with the increase of time. Additionally, the longitudinal elongation of composite geomembrane materials is proved to be located in a reasonable range, and there is no obvious upward or downward trend. The permeability coefficient of composite geomembrane material varies with the aging time, however, the test result remains in the same order of magnitude. The longitudinal tensile strength of composite geomembrane in dry state is larger than that in immersed state. The strength of the welded joint of geomembrane is larger than that of the bonded joint. The yield strength and breaking strength of geomembrane materials increase slightly with time, and there exists no significant changes in terms of the yield elongation and breaking elongation.
Analysis of deformation and failure characteristics of undisturbed loess under three axis test
Authors: Lei Guangyu , Xie Xiao
Published: September 2019

The water content has a very obvious influence on the deformation and strength characteristics of loess, which is related to the safety of geological environment. In this paper, the triaxial test of loess is carried out, and the deformation characteristics of the loess are studied. The strength characteristics of different loci are studied. The study shows that as the water content increases, the effective cohesion of loess decreases and the effective internal friction angle changes. The amplitude is not large, indicating that the water content only affects the effective cohesion of the loess and does not affect the effective internal friction angle. When the water content reaches a certain value, the effective cohesion is no longer reduced and remains stable. The corresponding moisture content corresponds to the plastic limit. The Mohr-Coulomb strength theory is suitable for fitting shear failure and bulging deformation. While Griffith The strength theory is more suitable for fitting the splitting failure, indicating that the strength theory suitable for different failure modes is different.
Rational curves in the logarithmic multiplicative group
Authors: Ranganathan Dhruv , Wise Jonathan
Published: September 2019

The logarithmic multiplicative group is a proper group object in logarithmic schemes, which morally compactifies the usual multiplicative group. We study the structure of the stacks of logarithmic maps from rational curves to this logarithmic torus, and show that in most cases, it is a product of the logarithmic torus with the space of rational curves. This gives a conceptual explanation for earlier results on the moduli spaces of logarithmic stable maps to toric varieties.
Mixing time and eigenvalues of the abelian sandpile Markov chain
Authors: Jerison Daniel , Levine Lionel , Pike John
Published: September 2019

The abelian sandpile model defines a Markov chain whose states are integer-valued functions on the vertices of a simple connected graph

G
G

. By viewing this chain as a (nonreversible) random walk on an abelian group, we give a formula for its eigenvalues and eigenvectors in terms of “multiplicative harmonic functions” on the vertices of

G
G

. We show that the spectral gap of the sandpile chain is within a constant factor of the length of the shortest noninteger vector in the dual Laplacian lattice, while the mixing time is at most a constant times the smoothing parameter of the Laplacian lattice. We find a surprising inverse relationship between the spectral gap of the sandpile chain and that of simple random walk on

G
G

: If the latter has a sufficiently large spectral gap, then the former has a small gap! In the case where

G
G

is the complete graph on

n
n

vertices, we show that the sandpile chain exhibits cutoff at time

1

4

π

2

n

3

log
⁡
n

\frac {1}{4\pi ^{2}}n^{3}\log n

.