Application of Artificial Neural Network in Predicting the Thickness of Chromizing Coatings on P110 Steel

A series of rare earth （RE） dispersed chromizing coatings were produced on P 110 steel by pack cementation. The orthogonal array design （OAD）was applied to set the experiments. An artificial neural network （ANN） approach is employed to predict the thickness values of the obtained chromizing coatings based on the OAD tests results. The results revealed that the built model was reliable, the thickness values of chromizing coatings were well predicted at selected process parameters, and the predicted error lied in rational range.

Science Letters: Equivalent thickness of materials of fused silica and stainless steel in the flow of microtubes

The deviation of flow characteristics from the predictions of the conventional theory for microtubes was attrib- uted to the change of fluid viscosity resulted from the interactions between the molecules on solid wall and in fluid. The degree of this departure is dependent on the microtubes materials. A concept of equivalent thickness with which conventional theory can be used to predict the flow in microtubes without modifying the fluid viscosity was put forward. The values of equivalent thickness for fused silica and stainless steel materials were determined as 1.8 μm and 1.5 μm, respectively, by repeated numeri- cal simulation.

Ultrasonic Evaluation of the Lens Thickness to Axial Length Factor in Primary Closure Angle Glaucoma

Ultrasonic biometry was done in 232 normal eyes and 138 eyes with primary angle closure glaucoma (ACG), using Ultrascan Digital B System IV (10 MHz). The ratio between the lens thickness and the axial length (lens thickness to axial length factor, LAF) was evaluated as a biometric index for assessing the eye with primary ACG in Chinese. LAF of 2.00 was found to be ideal point of demarcation between ACG and normal eyes (i.e., lens thickness equals to 1/5 of axial length). It appears that LAF is helpful i...

Research and application on the automatic measuring device for testing transverse thickness difference of cold-rolling steel sheet

Many advanced technologies have been applied in developing the automatic measuring device for testing transverse thickness difference of cold-rolling steel sheet,such as the technologies of automatic control,sensor measurement,marking identification,photographic location,computer application and information transmission.This measuring device can measure the transverse thickness difference of the steel plate accurately and quickly,with a high detection level of automation.It is an effective detection equipment for transverse thickness control of steel plate.Horizontal width of steel plate measuring 0.8-1.4 m, horizontal measurement point positioning accuracy±0.02 mm,thickness range 0.2-2.0 mm, measurement accuracy within±1μm.

Small-angle neutron scattering study on the stability of oxide nanoparticles in long-term thermally aged 9Cr-oxide dispersion strengthened steel

A 9 Cr-oxide dispersion strengthened(ODS)steel was thermally aged at 873 K for up to 5000 h.The size distribution and chemical composition of the dispersed oxide nanoparticles were analyzed by small-angle neutron scattering under a magnetic field.Combined with transmission electron microscopy,Vickers micro-hardness tests and electron backscattered diffraction measurements,all the results showed that the thermal treatment had little or no effect on the size distributions and volume fractions of the oxide nanoparticles in the ferromagnetic matrix,which suggested excellent thermal stability of the 9 Cr-ODS steel.

Regardless of the Puncture Angle, a Tuohy Needle with Sand-Blasted Steel at the Tip of the Bevel Is a Valid Needle on the Ultrasonic Images

Background: A high ability to visualize the needle on the ultrasonic images is necessary to perform the ultrasound-guided nerve block safely. The Rafa Tuohy needleR (Vygon, Paris, France, Rafa) is a non-stimulating Tuohy needle with sand-blasted steel at the tip of the bevel. We examined the degree to which the Rafa enhanced the visibility of ultrasonic images compared with the non-coated Tuohy needle. Methods: We punctured the Blue Phantom. The dimensions of both the Rafa and the non-coated Tuohy needles were 18 G × 80 mm. The puncture angle is 30 degrees and 45 degrees from the Blue Phantom. We measured the intensity of the tip of the bevel at a depth of 0.5, 1.0, 1.5 and 2.0 cm for the puncture angle of 30 degrees, and 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0 cm for the puncture angle of 45 degrees. Six anesthesiologists with more than seven years of experience performed three punctures using each needle. Results: As an outcome, we concluded that at a puncture angle of both 30 degrees and 45 degrees, the intensity of the non-coated Tuohy needle decreased with the depth. On the other hand, at an angle of 30 degrees, the intensity of the Rafa needle did not decrease, and at an angle of 45 degrees the intensity only decreased very slightly as the depth increased. Conclusions: The Tuohy needle with sand-blasted steel at the tip of the bevel provided greater visualization than the non-coated Tuohy needle on the ultrasound images.

The development and design of the repair welding procedure of the thick wall duplex stainless steel piping

In this paper,the performance characteristics of ASTM A790 S31803 and ASTM A182 F51 duplex stainless steel were introduced,and the weldabilities were analyzed. The welding repair procedures of thick wall duplex stainless steel were developed by welding procedure qualification. Research shows that the repair welding has less effect on mechanical properties of welded joint, and great influence on phase proportions and pitting corrosion resistance. The test results meet the requirements of project specifications. The repair welding procedure can be used in project,and only one time repair shall be used.

The comparison between laser screw welding and resistant spot welding of lap joint with large thickness ratio

The present paper investigates the welding forming,microstructure and shear tensile test of lap joints with large thickness ratio which were fabricated by laser screw welding(LSW)and resistant spot welding(RSW).The comparison was conducted on two kinds of lap joints,galvanized sheet and hot pressed steel(GS-HPS),galvanized sheet and high strength steel(GS-HS).The microstructure and fracture morphology were analyzed by optical microscope.It was demonstrated that with large thickness ratio the sound lap joint of GS-HS could be obtained by LSW regardless of the irradiation of laser beam from thick metal to sheet or otherwise,and the morphology shows it is better when the laser is irradiated on the thick metal.Nevertheless,when the laser beam was applied on thick metal of HPS,blind hole or blowhole was formed in the center of joint,which is attributed to the shrinkage during solidification of the molten pool.Small pores or dispersed porosity appeared on the faying face of the joint without predetermined gap which provides the degassing.However,the increase of predetermined gap could reduce the shear strength and nugget size.Two kinds of joints made by LSW have superior shear strength than those made by RSW when the laser were applied on galvanized sheet.

Experimental Study on the Effect of Steel-fibre in Concrete Thick Cap

The effect of steel fibre used in concrete was systematically analyzed by model testing of 30 2-pile thick caps of steel-fibre reinforced concrete, in which the model scale was 1：5. The experiment system composed of a loading device, strain measurement system and a data-acquisition system was used, also an electromechanic centigrade scale, a lens and a Y J-25 static resistance strainometer were used.The experimental results show that the volumetric rate of steel fibre and draw ratio have an important influence on its load-bearing capacity. The incorporation of steel fibre can effectively improve the extension and reduce the thickness of the caps.

STUDY ON THE MECHANISMS OF EROSION OF METALS AT LOW IMPACT ANGLE

The mechanisms of solid particle erosion of several pure metals and steels at low impact angle were studied comprehensively by SEM observations of the worn surface,wear debris analysis, subsurface hardness measurements,incremental erosion tests and sequential erosion study techniques. It was found that at the beginning of erosion,craters and lips were formed on the surfaces of ductile metals due to the deformation caused by the impacting of the particles. The deformed lips were then forged back and forth again and again in erosion process. As a result , small chips of deformed lips were stripped off continuously in the process. All of the evidences show that the erosion mechanisms are encompassed mainly by the process of plastic deformation,lip formation and spelling with ductile metals,while microcutting is more easy to occur with hardened steels.

Effect of Thermal Shrinkage of Extruded Sheet on Mouthguard Thickness: Influence of Model Undercut

The effectiveness and safety of the mouthguard are greatly affected by its thickness. The aim of this study was to investigate the effect of thermal shrinkage of the extruded sheet on the mouthguard thickness depending on the amount of undercut of the model. Mouthguard sheet was used a 4.0 mm thick ethylene-vinyl acetate resin manufactured by extrusion molding. The sheets were placed in the vacuum forming machine with the sheet extrusion direction either vertical (condition V) or parallel (condition P) to the model’s centerline. The working models were three hard plaster models trimmed so that the angles of the anterior teeth to the model base were 90?, 100?, and 110? (Models A, B, and C). The sheet was softened until it sagged 15 mm, and then suction was continued for 30 s. Measurement points of the mouthguard were the incisal portion (incisal edge and labial surface) and molar portion (cusp and buccal surface). The differences in the reduction rate of the thickness due to model form and extrusion direction were analyzed using two-way ANOVA and Bonferroni’s multiple comparison tests. Differences in thickness depending on the extrusion direction of the sheet were observed in Models B and C on the labial surface and in all models on the buccal surface, and the thicknesses obtained under condition P were significantly thinner than those obtained under condition V. The thicknesses of the incisal edge and the cusp were not affected by the extrusion direction. The result of this study was suggested that the labial and buccal thickness of the mouthguard was secured by placing the sheet in the extrusion direction vertical to the model’s centerline. Furthermore, it was clarified that the presence of the undercut of the model tends to increase the influence of the extrusion direction of the sheet on the thickness of the mouthguard.

Study on Interactive Computer Program for Seismic Appraisal and Seismic Strengthening of R.C. Frame Structures

In many cases, seismic appraisal of existing structures is carried out by the two step method and seismic strengthening of R.C. frame structures is solved just based on rough calculation or experience of designers, which may lead to either lack of safety or too conservative in design. According to some related criteria and experts experience, a computer program is developed specially for seismic appraisal and seismic strengthening of R.C. frames (not more than 10 storeys) in this paper. Because the progra...

Formation mechanism and control of aluminum layer thickness fluctuation in embedded aluminum-steel composite sheet produced by cold roll bonding process

The influences of rolling reduction and aluminum sheet initial thickness(AIT)on the thickness fluctuation of aluminum layer(TFA)of embedded aluminum?steel composite sheet produced by cold roll bonding were investigated,the formation mechanism of TFA was analyzed and method to improve the thickness uniformity of the aluminum layer was proposed.The results showed that when the reduction increased,TFA increased gradually.When the reduction was lower than40%,AIT had negligible effect on the TFA,while TFA increased with the decrease of AIT when the reduction was higher than40%.The non-uniformities of the steel surface deformation and the interfacial bonding extent caused by the work-hardened steel surface layer,were the main reasons for the formation of TFA.Adopting an appropriate surface treatment can help to decrease the hardening extent of the steel surface for improving the deformation uniformity during cold roll bonding process,which effectively improved the aluminum thickness uniformity of the embedded aluminum/steel composite sheets.

Research on reasonable winding angle of ribbons of Flat Steel Ribbon Wound Pressure Vessel

Flat Steel Ribbon Wound Pressure Vessels (FSRWPVs) are used in many important industry areas. There is no such kind of pressure vessel exploding on operation for its reasonable structure design. Many explosion experiments on Flat Steel Ribbon Wound Pressure Vessel showed that their limited load pressure is related to the winding angle of the steel ribbons. FSRWPVs with reasonable winding angle have better security and lower cost. Reasonable angels given at the end of this paper facilitate engineering design.

Design and application of thickness measurement calibration system based on laser displacement sensor

This study aims to improve the accuracy and safety of steel plate thickness calibration.A differential noncontact thickness measurement calibration system based on laser displacement sensors was designed to address the problems of low precision of traditional contact thickness gauges and radiation risks of radiation-based thickness gauges.First,the measurement method and measurement structure of the thickness calibration system were introduced.Then,the hardware circuit of the thickness system was established based on the STM32 core chip.Finally,the system software was designed to implement system control to filter algorithms and human-computer interaction.Experiments have proven the excellent performance of the differential noncontact thickness measurement calibration system based on laser displacement sensors,which not only considerably improves measurement accuracy but also effectively reduces safety risks during the measurement process.The system offers guiding significance and application value in the field of steel plate production and processing.

Effect of fiber angle on LYP steel shear walls behavior

Steel shear wall(SSW) was properly determined using numerical and experimental approaches.The properties of SSW and LYP(low yield point) steel shear wall(LSSW) were measured.It is revealed that LSSW exhibits higher properties compared to SSW in both elastic and inelastic zones.It is also concluded that the addition of CFRP(carbon fiber reinforced polymers) enhances the seismic parameters of LSSW(stiffness,energy absorption,shear capacity,over strength values).Also,stress values applied to boundary frames are lower due to post buckling forces.The effect of fiber angle was also studied and presented as a mathematical equation.

Intraocular retinal thickness asymmetry in early stage of primary open angle glaucoma and normal tension glaucoma

AIM： To investigate the intraocular retinal thickness asymmetry of peripapillary retinal nerve fiber layer（pR NFL） and macular layers measured by spectral-domain optical coherence tomography（SD-OCT） in patients with early stage of primary open angle glaucoma（POAG） and normal tension glaucoma（NTG）.METHODS： A total of 117 patients with early stage of glaucoma（54 patients with POAG and 63 patients with NTG） and 32 normal subjects were recruited for the study. The pR NFL thickness, total macular layer（TML） thickness, and isolated inner macular layer（IML） thickness were measured by SD-OCT. Hemisphere TML thickness asymmetry measured by the posterior pole asymmetry scan was evaluated. Thickness differences of pR NFL and IML between superior and inferior quadrants were calculated. Asymmetry indices（AIs） of the p RNFL, TML and isolated IML were also computed. Areas under the receiver-operating characteristic curves（AROCs） were generated to determine the diagnostic capabilities of different parameters. RESULTS： Intraocular p RNFL thickness differences and AIs between the superior and inferior quadrants were significantly different between normal and NTG groups（P=0.009 and P〈0.001, respectively）. Intraocular p RNFL thickness differences and AIs between the temporal-superior and temporal-inferior sectors were also significantly different between normal and NTG groups（P=0.035 and P〈0.001, respectively）. The thickness differences and AIs of TML between superior and inferior hemispheres were significantly different between normal and NTG groups（P=0.001 and P=0.001, respectively） and between normal and POAG groups（P=0.032 and P=0.020, respectively）. The thickness differences and AIs of macular ganglion cell layer（mG CL） between superior and inferior quadrants were significantly different between normal and NTG groups（P=0.013 and P=0.004, respectively）, and between NTG and POAG groups（P=0.015 and P=0.012, respectively）. The thickness difference of TML between superior and inferior hemispheres showed the highest diagnostic capability for early NTG eyes（AROC=0.832）.CONCLUSION： Intraocular retinal thickness asymmetry in pR NFL, TML and mG CL are found in early stage of NTG. Hemisphere TML thickness asymmetry is also found in POAG eyes. Asymmetry analysis of retinal thickness can be an adjunctive modality for early detection of glaucoma.

Dynamic performance of angle-steel concrete columns under low cyclic loading-I:Experimental study

This paper describes low cyclic loading testing of nine angle-steel concrete column （ASCC） specimens. In the tests, the influence of the shear-span ratio, axial compression ratio and shear steel plate ratio on the hysteretic behavior, energy dissipation, strength degradation, stiffness degradation, skeleton curve and ductility of the ASCCs is studied. Based on the test results, some conclusions are presented. The P-A and sectional M -φ hysteretic models for the ASCCs are presented in a companion paper （Zheng and Ji, 2008）.

Dynamic performance of angle-steel concrete columns under low cyclic loading-II:parametric study

Tests of nine angle-steel concrete column （ASCC） specimens under low cyclic loading are described in a companion paper （Zheng and Ji, 2008）. In this paper, the skeleton curves from the numerical simulation are presented, and show good agreement with the test results. Furthermore, parametric studies are conducted to explore the influence of factors such as the axial compression ratio, shear steel plate ratio, steel ratio, prismatic concrete compression strength, yield strength of angle steel and shear span ratio, etc., on the monotonic load-displacement curves of the ASCCs. Based on a statistical analysis of the calculated results, hysteretic models for load-displacement and moment-curvature are proposed, which agree well with the test results. Finally, some suggestions concerning the conformation of ASCCs are proposed, which could be useful in engineering practice.

Optical coherence tomography evaluation of retinal nerve fiber layer thickness in non-arteritic anterior ischemic optic neuropathy and primary open angle glaucoma:a systematic review and Meta-analysis

AIM:To assess the differences in average and sectoral peripapillary retinal nerve fiber layer(p RNFL)thickness using spectral domain optical coherence tomography(SD-OCT)in patients with non-arteritic anterior ischemic neuropathy(NAION)compared with those with primary open angle glaucoma(POAG).METHODS:A comprehensive literature search of the Pub Med,Cochrane Library,and Embase databases were performed prior to October,2021.Studies that compared the p RNFL thickness in NAION eyes with that in POAG eyes with matched mean deviation of the visual fields were included.The weighted mean difference(WMD)with 95%confidence interval(CI)was used to pool continuous outcomes.RESULTS:Ten cross-sectional studies(11 datasets)comprising a total of 625 eyes(278 NAION eyes,347 POAG eyes)were included in the qualitative and quantitative analyses.The pooled results demonstrated that the superior p RNFL was significantly thinner in NAION eyes than in POAG eyes(WMD=-6.40,95%CI:-12.22 to-0.58,P=0.031),whereas the inferior p RNFL was significant thinner in POAG eyes than in NAION eyes(WMD=11.10,95%CI:7.06 to 15.14,P≤0.001).No difference was noted concerning the average,nasal,and temporal p RNFL thickness(average:WMD=1.45,95%CI:-0.75 to 3.66,P=0.196;nasal:WMD=-2.12,95%CI:-4.43 to 0.19,P=0.072;temporal:WMD=-1.24,95%CI:-3.96 to 1.47,P=0.370).CONCLUSION:SD-OCT based evaluation of inferior and superior p RNFL thickness can be potentially utilized to differentiate NAION from POAG,and help to understand the different pathophysiological mechanisms between these two diseases.Further longitudinal studies and studies using eight-quadrant or clock-hour classification method are required to validate the obtained findings.