Lining Cavity Research Articles

Research on wavelet packet energy entropy extraction method for acoustic signal of tunnel lining cavity

Abstract Tunnel lining cavity is a common disease in high-speed railway tunnels, which seriously affects the safe operation of the line.At present, the commonly used method is manual knocking inspection, but it relies on manual judgment, subjective factors have great influence, and there are errors. This paper proposes a feature extraction method of acoustic vibration signal of tunnel lining cavity based on wavelet packet energy entropy and uses wavelet packet energy entropy to realize the identification of cavity defects.The full-scale simulation model of tunnel with a radius of 6m was constructed by COMSOL and different cavity conditions were set up. The wavelet packet energy entropy characteristics of acoustic signals were extracted and analyzed. The mapping relationship between cavity depth and cavity size and wavelet packet energy entropy was explored. The wavelet packet energy entropy and frequency band distribution characteristics were extracted to realize the identification of cavity defects.The local model which can characterize the whole tunnel is designed and the embedded defects are verified by experiments. The results show that the wavelet packet energy entropy can be used as the identification feature of tunnel lining cavity defects. When the wavelet packet energy entropy is less than 2.53, the existence of tunnel lining cavity defects is characterized.When the wavelet packet energy entropy is in the range of 2.53-2.94, it characterizes the existence of the transition boundary between tunnel lining cavity defect and no disease.This index can be used to realize the rapid and effective identification of cavity defects.

Acoustic tunnel lining cavity detection using cepstral coefficients with optimized filter bank

Tunnels are an essential component of modern transportation infrastructure, and their structural health is critical to traffic safety, which can be seriously affected by tunnel lining cavities. In this paper, an acoustic-based detection approach for assessing the integrity of tunnel linings is studied. By tapping the tunnel lining surface, acoustic signals are sampled and analyzed using a novel feature parameter extraction algorithm-the energy-frequency cepstral coefficient, which uses wavelet packet decomposition to obtain energy distribution statistics in the frequency domain of the signal, and constructs a signal-dependent filter bank to achieve the cepstral coefficient extraction. Compared with the traditional Mel filter bank, this method can adaptively adjust the resolution of the filter bank according to the frequency characteristics of the classified samples. This allows for higher frequency resolution in regions where the energy distribution is concentrated. As a result, the extracted feature parameters achieve both dimensional compression and superior information retention. Experimental results show that the proposed energy-frequency cepstral coefficient feature outperforms the traditional Mel-frequency cepstral coefficient feature, resulting in a higher accuracy of tunnel lining detection. The convolutional neural network model achieves an accuracy of 99.2%, with a 78.9% reduction in error rate compared with the traditional Mel-frequency cepstral coefficient feature parameters. Additionally, a particle swarm optimization support vector machine model is trained to achieve an accuracy rate of 99.6% and an error rate reduction of 76.5%.

SURG-31. DEFINING THE NEW POSSIBILITIES FOR CESIUM BRACHYTHERAPY IN PATIENTS WITH PERIVENTRICULAR GBM

Abstract INTRODUCTION Re-irradiation of patients with external beam radiotherapy (EBRT) for recurrent glioblastoma (GBM) continues to present a therapeutic dilemma due to a high risk of radiation induced necrosis (RN). In contrast, brachytherapy represents a safer, more conformal radiation option aimed at optimizing local control while minimizing the risk of brain tissue damage. Immediate intra-operative implantation with brachytherapy prevents tumor repopulation and offers patients two procedures in one setting. However, due to the risk of seed migration, surgical resection and brachytherapy in periventricular regions was deemed unachievable. In heavily pretreated periventricular GBM, where further EBRT is complicated by RN, a barrier between the ventricular lining and tumor cavity is needed to prevent seed migration. We present two patients where such a barrier allowed successful implantation of brachytherapy to improve disease control. METHODS Two patients, previously treated with surgery and EBRT, presented with recurrent GBM abutting the ventricles. Following GTR of the tumors, a barrier was created by patching the ventricle with Gelfoam to prevent seed migration. Intraoperative brachytherapy implantation of suture stranded Cs-131 seeds (Isoray) for patient 1 and collagen embedded Cs-131 (GammaTile) for patient 2 was performed. A total of 20 Cs-131 seeds on strings threaded through Surgicel, and 6 GammaTiles (24 Cs-131 seeds), were used implanted in patients 1 and 2, respectively. Surgicel covered the implanted seeds and the resection cavity filled with Adherus. RESULTS Post-operative CT scan demonstrated all 20 Cs-131 seeds and 24 Cs-131 seeds in the surgical cavities of patients 1 and 2, respectively, and had serial post operative imaging with MRI scans showing Cs-131 seeds layering surgical cavity, as late as 6 months in total follow up. To date, both patients have had durable local control and no seed migration.

Analysis of Stratigraphic Subsidence Caused by Sand Leakage in Tunnel Lining

According to the phenomenon of stratigraphic subsidence caused by sand leakage in tunnel engineering, the process of sand surging was compared with the process of material discharging in the silo, the sand in the flat-bottom silo and its discharge bore and sand was used to simulate the lining structure, lining cavity and the sand in the stratum behind the lining in the tunnel engineering respectively. Through the design of indoor sand leakage experiment system, sand leakage experiment was carried out in the flat-bottom silo to discussed that under the condition of constant bore diameter, the influence of different thickness-to-span ratio on sand settlement range, settlement trough, the amount of sand leakage, and the influence of different bore size on sand leakage velocity under the condition of different bore diameter, and the critical crack ratio and flow pattern of sand were analyzed. The results showed that when the diameter of the bore was constant, the influential radius of settlement was basically linear with the thickness-to-span ratio as the soil thickness increased, and the proportion of sand loss to the total sand also increased, when the diameter of bore was different, the leakage velocity increased with the increase of the bore diameter, and the function relation could be described by the quadratic curve. There was a critical state for the collapse of sand, when the ratio of the diameter of the bore to the diameter of the sand particles did not exceed this critical state, the sand would form a stable soil arch structure above the bore, preventing the further development of sand leakage; when the collapse of sand occurred, the larger the diameter of the underground cavity, the greater the depth of the erosion, the greater impact on the ground.

Application of GPR reverse time migration in tunnel lining cavity imaging

Correctly locating the tunnel lining cavity is extremely important tunnel quality inspection. High-accuracy imaging results are hard to obtain because conventional one-way wave migration is greatly affected by lateral velocity change and inclination limitation and because the diffracted wave cannot be accurately returned to the real spatial position of the lining cavity. This paper presents a tunnel lining cavity imaging method based on the ground-penetrating radar (GPR) reverse-time migration (RTM) algorithm. The principle of GPR RTM is described in detail using the electromagnetic wave equation. The finite-difference timedomain method is employed to calculate the backward extrapolation electromagnetic fields, and the zero-time imaging condition based on the exploding-reflector concept is used to obtain the RTM results. On this basis, the GPR RTM program is compiled and applied to the simulated and observed GPR data of a typical tunnel lining cavity GPR model and a physical lining cavity model. Comparison of RTM and Kirchhoff migration results reveals that the RTM can better converge the diffracted waves of steel bar and cavity to their true position and have higher resolution and better suppress the effect of multiple interference and clutter scattering waves. In addition, comparison of RTM results of different degrees of noise shows that RTM has strong anti-interference ability and can be used for the accurate interpretation of radar profile in a strong interference environment.

The crucial techniques of water leakage treatment in operating highway tunnel

Tunnel leakage is a common disaster in operating highway tunnel, causing many adverse effects on tunnel stability, cave facilities, traffic safety and the environment. Based on the causes and hazards of operating highway tunnel leakage, the tunnel leakage is divided into four types : construction joints leakage, lining crack leakage, fracture and cavity behind the lining leakage, concrete lining damage leakage. And the related crucial techniques and schemes were proposed. The achievements have been widely applied in Kaiyuan tunnel successfully, which offers a reference for similar tunnels.

Fire resistance of non-load bearing LSF walls with varying cavity depth

Abstract Fire resistance of Light Gauge Steel Frame (LSF) wall systems is important in the emerging mid-rise cold-formed steel construction. Many studies have been conducted in recent times to improve the acoustic, thermal (energy) and fire performance of non-load bearing LSF walls. Increasing the wall cavity depth provides superior acoustic and thermal performance characteristics of LSF walls. LSF walls with increased cavity depth are constructed using different stud arrangements such as single, double and staggered rows of studs. Past research studies have been limited to non-load bearing LSF walls made of single row of steel studs with the same cavity depth of 90 mm. This paper investigates the fire resistance of single, double and staggered stud LSF walls with varying cavity depths under non-load bearing conditions. Four full-scale standard fire tests were conducted to investigate the effects of cavity depth for non-load bearing LSF walls and the results are presented in detail. Fire test results show that the temperatures across the wall depth decrease with increasing cavity depth. LSF walls with two layers of plasterboard lining and wider cavity resulted in increased fire resistance. This study also highlights the detrimental effects of staggered stud LSF wall arrangement causing structural failure of thin-walled steel studs.

GPR Detection of Tunnel Lining Cavities and Reverse-time Migration Imaging

Tunnel lining cavity is one of the diseases that threaten the safe operation of tunnel, so it has been the attention of test personnel. As a nondestructive testing method, Ground Penetrating Radar (GPR) has been widely used in tunnel lining disease inspection. In order to improve the detection accuracy and success rate of tunnel lining cavities, this paper applies the reverse-time migration (RTM) algorithm to image tunnel lining cavities with high accuracy. Firstly, the principle of GPR pre-stack RTM is described in detail, in which the finite difference time domain (FDTD) method is used to calculate the forward and backward electromagnetic fields, and the normalized cross-correlation imaging condition is used to obtain the RTM results. On this basis, the GPR RTM program is compiled and applied to the simulated dataset of a typical lining cavity GPR model. The comparison of RTM and Kirchhoff migration result showed that the diffracted wave in the steel bar and cavities has good convergence, and the profile’s resolution is improved effectively; In contrast to the Kirchhoff migration result, the RTM result can better focus the radar diffraction wave energy of the steel bars and cavities on the real space location generated by them, weaken the shielding effect of the steel mesh, and suppress multiple interference and clutter scattering waves. Finally, a physical model of lining cavities was detected by GPR, and the RTM algorithm was applied to data processing and interpretation. The RTM delimits the positions of steel mesh and cavities effectively, and the interpretation accuracy of GPR profile has been improved, which provide a scientific and effective way for accurately delimit the scope of tunnel lining cavities.

Research on Tunnel Lining Cavity Treatment Technology of a Metro Tunnel in Chongqing

The hollowing problem of tunnel lining structure is like a suspended bomb, which may affect the safety of vehicles and the safety of passengers at any time. Therefore, the study of tunnel lining structure cavity management technology has great social significance for ensuring tunnel safety. Taking a metro tunnel in Chongqing as an example, this paper proposes a reasonable lining structure reinforcement scheme of changing partial arches and reinforcing by steel strips after analyzing the environment, the bearing requirements, and the size and location of cavities. Based on the calculation formula of flexural members given by Code for Design of Concrete Structure Reinforcement, reduction system is introduced to calculate safety coefficient of flexural and compression members. The minimum value of structural bearing after treatment is 4.4, which meets the requirement of bearing capacity. Stratum structure method is used to calculate surrounding rock deformation during reinforcement. The maximum horizontal displacement is 1.9 mm, and the vertical displacement is 6 mm. The surrounding rock could be stable when treating defects, and the treatment scheme meets the requirements of bearing capacity and inner clearance. Therefore, the tunnel lining structure cavity can be reinforced by means of shotcrete and steel strips, without interrupting traffic and ensuring driving safety. The success of the treatment provides a useful reference for other similar projects.

From the "Shandong Embroidery" Light "Clan Folk Song" Research Value

From the "Shandong Embroidery" Light "Clan Folk Song" Research Value

The Research of Detection and Treatment of Tunnel Lining Cavity

It was a threat that the lining cavity had a many risk of the tunnel operation, thus detection and prevention was particularly important. The general causes of tunnel lining cavity and corresponding prevention measures will be summarized, and methods which includes detect lining cavity and processing data were given. Last, a real engineering was given for illustrating the practical method of tunnel lining cavity detection process. The proposed method has a great significance to ensure the safety of the tunnel operation.

An In Situ Gelling Buccal Spray Containing Platelet Lysate for the Treatment of Oral Mucositis

Oral mucositis is an inflammatory disease of the mucosa lining oral cavity which leads to atrophy of the epithelium and to its ulceration to form chronic lesions. Many studies, both in vitro and in vivo, have disclosed the effectiveness of growth factors derived from platelets to enhance cell proliferation, differentiation, chemotaxis, angiogenesis and extracellular matrix synthesis involved in the healing of tissues. Despite potential usefulness of growth factors, animal-derived or genetically engineered ones are currently scarcely available for regenerative therapies. The aim of the present work was to study an in situ gelling formulation to be delivered by a spraying device to the oral cavity affected by mucositis. A vehicle based on Poloxamer 407 (F127) and sodium alginate (LVG) was developed. An extemporaneous loading of the vehicle with PL was achieved. The formulation was able to quickly thermogelify at 34-35°C with a viscosity at 8°C suitable for spraying; moreover it was characterized by good mucoadhesive properties. ELISA assay evidenced that at time zero the growth factor PDGF AB was compatible with the vehicle. The in vitro wound healing test showed that the formulation enhanced cell growth as PL alone even after 72 h of contact without cell apoptosis. The overall results indicate that PL loaded in the in situ gelling F127 and LVG vehicle can be profitably employed to treat buccal mucositis.

Human malignant pleura mesothelioma ‐ a three‐dimensional (3D) tumor model

Human malignant pleura mesothelioma (MPM) is an extremely aggressive tumor of the mesothelium lining pleural cavity. Once diagnosed, it is uniformly fatal, with a median survival ranging from 4 to 12 month. The aim of our study is to design a 3D MPM model, to get knowledge of the biologic processes, which promote and maintain the uncontrolled proliferation of MPM cells, because the use of monolayer (2D) cultures does not accurately reflect the behaviour of cells in vivo. Human anchorage-depended MPM cells were seeded with macroporous gelatine microcarriers in the NASA-developed Rotary Cell Culture System™ (RCCS™). By simulating weightlessness (10−2 g) cells are maintained in a dynamic fluid suspension. Cells were examined at the state of viability, growth, morphology, differentiation and protein level in comparison to 2D controls. Different tumor marker were evaluated by immunohistochemistry, and the secretion of mucoglycoproteins by Alcian Blue staining. In addition, a comparative proteomic profile was established by 2D gel elektrophoreses and MALDI-TOF MS. Morphology, cell-cell junctional complexes and the well-developed formation of microvilli was shown by electron microscopy. The resulting morphological and functional differentiated tumor spheroids (5 mm in average) displayed a distinct protein pattern, than the control. Interestingly, the MPM marker Calretinin and Vimentin are expressed in a different manner. The organized 3D arrangement of mesothelioma cells with different phenotypes such as proliferating, non-proliferating, necrotic cells and extracellular matrix-interactions, represents the histological complexity of MPM tissue in-vivo. In conclusion, we find that this 3D in vitro culture is a credible and reliable preclinical tumor model.

Immunohistochemical staining characteristics of the L-selectin ligand in hormonally programmed and natural cycle luteal endometrium

Immunohistochemical staining characteristics of the L-selectin ligand in hormonally programmed and natural cycle luteal endometrium

Inhibition of interleukin-1-induced synovitis and articular cartilage proteoglycan loss in the rabbit knee by recombinant human interleukin-1 receptor antagonist

Intra-articular injection of interleukin-1 (IL-1) into the knee joints of rabbits produces a synovitis associated with the loss of proteoglycan from the matrix of articular cartilage. This experimental finding supports the hypothesis that IL-1 is a possible mediator of the pathology of inflammatory joint diseases and suggests that antagonism of IL-1 could offer a therapeutic approach to these diseases. It has recently been reported that culture of human monocytes on adherent IgG stimulates these cells to synthesize a specific inhibitor of IL-1 bioactivity (IL-1ra) that acts as a receptor antagonist with lymphocytes and mesenchymal cells. We have now shown that intravenous injection of IL-1ra into rabbits given an intra-articular injection of recombinant IL-1β not only inhibits the entry of leukocytes into the synovial lining and joint cavity but blocks the ability of IL-1 to cause loss of proteoglycan from articular cartilage. This ability of IL-1ra to inhibit IL-1-induced arthritis in the rabbit reveals that this protein has appropriate pharmacokinetic and pharmacodynamic properties and further strengthens the belief that it may be a useful therapeutic agent.

Comparison of the in vivo inflammatory activities after intra-articular injection of natural and recombinant IL-1α and IL-1β in the rabbit

Comparison has been made of the in vivo pro-inflammatory activities or porcine natural and human recombinant α and β interleukin 1 (IL-1) after injection into the knee joints of rabbits. Both forms of pig IL-1 and human IL-1 were separately equiactive in vitro in stimulating rabbit synovial fibroblasts and articular chondrocytes to synthesize prostaglandin E 2 (PGE 2). Injection of IL-1 into the rabbit knee joint was not associated with swelling of the joint nor with the appearance of PGE 2 in the synovial fluid. However, all preparations of IL-1 induced a dose-dependent increase in inflammatory leukocytes in the synovial lining and joint cavity. In addition, both the α and β forms of IL-1 from both species caused loss of proteoglycan from the matrix of articular cartilage. This study demonstrates that both genetically distinct forms of IL-1 have the same range of inflammatory actions within the joint and that they have similar potencies in these respects.

Hemorrhagic cyst of the mandible associated with a retained root apex of the lower third molar

An unusual case of hemorrhagic cyst of the mandible, associated with a retained root of the lower right third molar, is reported. The cyst was revealed by routine radiologic examination as part of treatment of the lower right second molar. Radiologically, a faintly outlined cavity with radiopaque mass was found in the third molar region. A final diagnosis of this condition was made after surgical intervention and histologic examination. A nonepithelial lining cavity was found, and the radiopaque mass was identified as a root apex.

Fluid inclusions in rocks from the amphibolite‐facies gneiss to charnockite progression in southern Karnataka, India: direct evidence concerning the fluids of granulite metamorphism

Abstract Fluid inclusion studies of rocks from the late Archaean amphibolite‐facies to granulite‐facies transition zone of southern India provide support for the hypothesis that CO2,‐rich H2O‐poor fluids were a major factor in the origin of the high‐grade terrain. Charnockites, closely associated leucogranites and quartzo‐feldspathic veins contain vast numbers of large CO2‐rich inclusions in planar arrays in quartz and feldspar, whereas amphibole‐bearing gray gneisses of essentially the same compositions as adjacent charnockites in mixed‐facies quarries contain no large fluid inclusions. Inclusions in the northernmost incipient charnockites, as at Kabbal, Karnataka, occasionally contain about 25 mol. % of immiscible H2O lining cavity walls, whereas inclusions from the charnockite massif terrane farther south do not have visibile H2OMicrothermometry of CO2 inclusions shows that miscible CH4 and N2 must be small, probably less than 10mol.%combined. Densities of CO2 increase steadily from north to south across the transitional terrane. Entrapment pressures calculated from the CO2 equation of state range from 5 kbar in the north to 7.5 kbar in the south at the mineralogically inferred average metamorphic temperature of 750°C, in quantitative agreement with mineralogic geobarometry. This agreement leads to the inference that the fluid inclusions were trapped at or near peak metamorphic conditions.Calculations on the stability of the charnockite assemblage biotite‐orthopyroxene‐K‐feldspar‐quartz show that an associated fluid phase must have less than 0.35 H2O activity at the inferred P and T conditions, which agrees with the petrographic observations. High TiO2 content of biotite stabilizes it to lower H2O activities, and the steady increase of biotite TiO2 southward in the area suggests progressive decrease of aH2O with increasing grade. Oxygen fugacities calculated from orthopyroxene‐magnetite‐quartz are considerably higher than the graphite CO2‐O2 buffer, which explains the absence of graphite in the charnockites.The present study quantifies the nature of the vapours in the southern India granulite metamorphism. It remains to be determined whether CO2‐flushing of the crust can, by itself, create large terranes of largeion lithophile‐depleted granulites, or whether removal of H2O‐bearing anatectic melts is essential.

Lipopigment in odontogenic cysts.

A study of 105 odontogenic cysts revealed the presence of pigmented cells in the cyst wall in 38% of the cases. The frequency of pigmented cells was higher in the inflammatory odontogenic cysts than in the development cysts. Although isolated pigmented cells were seen within the epithelial lining and cyst cavity, the larger collections were closely associated with cholesterol crystals and hemosiderin deposits; they contained light brown cytoplasmic pigment which manifested sudanophilia, acid-fastness, silver reduction capacity, PAS positivity and yellow autofluorescence in ultraviolet light. The morphology, histochemical reactions and autofluorescence suggest that the pigmented cells are macrophages containing ceroids. It has been suggested that the hemosiderin which is found in the cyst wall serves as an oxidation catalyst for the locally liberated lipids, the end result of which is the formation of the ceroid pigment.