Analysis of the Manufactured Tolerances with the Three-Dimensional Method of Angular Chains of Dimensions Applied to a Cylinder Head of Car Engine

This paper proposes an analysis method of the manufactured tolerances applied to a cylinder head of car engine. This method allows to determine the manufacturing tolerances in the case of angular chains of dimensions and to check its correspondence with the functional tolerances. The objective of this work is to analyze two parameterized functions: the angular defect Δα and the projected length lg of the toleranced surface. The angular defects are determined from the precision of the machine tools, we consider only the geometrical defects (position and orientation of surfaces), making the assumption that the form defects are negligible. The manufactured defect is determined from these two parameterized functions. Then it will be compared with the functional condition in order to check if the selected machining range allows, at end of the manufacturing process, to give a suitable part.

Influence of forming process on three-dimensional morphology of TiB_2 particles in Al-Ti-B alloys

A series of Al-Ti-B master alloys were prepared by different preparation routes,and the TiB2 particles in the master alloys were extracted and analyzed.It is found that the forming process has significant influence on the three-dimensional morphology of TiB2 particles.Different preparation routes result in different reaction forms,which accounts for the morphology variation of TiB2 particles.When the Al-Ti-B master alloy is prepared using ＂halide salt＂ route,TiB2 particles exhibit hexagonal platelet morphology and are independent with each other.In addition,the reaction temperature almost does not have influence on the morphology of TiB2 particles.However,TiB2 particles exhibit different morphologies at different reaction temperatures when the master alloys are prepared with Al-3B and Ti sponge.When the master alloy is prepared at 850 ℃,a kind of TiB2 particle agglomeration forms with a size larger than 5 μm.The TiB2 particles change to layered stacking morphology even dendritic morphology with the reaction temperature reaching up to 1200 ℃.

Behavior of traditional concrete dams and three-dimensional printed concrete dams under the debris flow impact

This study investigated the resilience of traditional concrete dams compared to 3D printed concrete dams(3DPC)when subjected to debris flow.Three types of dams,namely check dams,arch dams,and curve dams,were numerically analyzed using a three-dimensional Coupled Eulerian-Lagrangian(CEL)methodology.The research focused on critical factors such as impact force and viscous energy dissipation to compare dam performance.Additionally,the study examined the printing and service phases of 3DPC models,determining potential failure modes and analyzing printing parameters.The results demonstrated that 3DPC dams outperformed traditional concrete dams,with filament deposition orientation,perpendicular to the debris flow direction,identified as a pivotal factor.Infill percentage and pattern were also found to influence the behavior of 3DPC models.Notably,curved dams exhibited superior performance based on dam geometry.These findings have significant potential for advancing the development of resilient dam structures capable of withstanding debris flow impacts.

A robust tolerance design method based on process capability

This paper presents a method for robust tolerance design in terms of Process Capability Indices (PCI) . The component tolerance and the suitable manufacturing processes can be selected based on the real manufacturing context. The robustness of design feasibility under the effect of uncertainties is also discussed. A comparison between the results obtained by the proposed model and other methods indicates that robust and reliable tolerance can be obtained.

Preparation of Dashanzha Wan by three-dimensional printing

Objective:To use three-dimensional(3D)printing technology to prepare Dashanzha Wan.Methods:The standard formula proportion of Dashanzha Wan was used to prepare printable materials(normally called the ink)for 3D printing,and different doses and shapes of Dashanzha Wan were prepared.Then,the rheological properties,texture characteristics,scanning electron microscopy,and content of ursolic acid were evaluated.Results:Dashanzha Wan ink showed good shear thinning properties,which is very suitable for 3D printing.The printed sample had a beautiful and regular shape with high resolution.Meanwhile,ursolic acid content in 3D-printed Dashanzha Wan aligned with the ursolic acid content shown in the Pharmacopoeia of the People's Republic of China 2020.Conclusion:The 3D-printed Dashanzha Wan has a better texture,and can be shaped into various shapes according to individual needs,which would increase patients’interest when taking medicine.Moreover,3D printing of Dashanzha Wan could be easily integrated into the digital life system,enabling online customization or use at home.This study reveals that 3D printing technology is a promising method for the production of traditional Chinese medicine with personalized appearance,dosage,and texture,which is suitable for a broader population.

Three-Dimensional Rigid-Plastic FEM Simulation of Bulk Forming Processes with New Contact and Remeshing Techniques

Some techniques such as die surface description, contact judgement algorithm and remeshing are proposed to improve the robustness of the numerical solution. Based on these techniques, a three-dimensional rigid-plastic FEM code has been developed. Isothermal forging process of a cylindrical housing has been simulated. The simulation results show that the given techniques and the FEM code are reasonable and feasible for three-dimensional bulk forming processes.

Simulation-Based Construction of Three-Dimensional Process Model for Punching Cartridge Cases

A method of constructing three-dimensional process model for the punching cartridge cases is presented based on DEFORM simulation analysis. Using DEFORM software,the finite element simulation models for the punching and forming process of cartridge cases are established,and the corresponding simulation result model of each intermediate procedure is obtained by continuously performing the forming process simulation. The simulation model cannot annotate size and process information due to poor interface between DEFORM software and CAD software. Thus,a 3D annotation module is developed with secondary development technology of UG NX software. Consequently,the final process model with dimension and process information is obtained. Then,with the current 3D process management system,the 3D punching and forming process design of cartridge cases can be completed further. An example is also provided to illustrate that the relative error between the simulation process model and the physical model is less than 2%,which proves the validity and reliability of the proposed method in this study.

Analysis and evaluation of effects of processing steps on dimensional tolerance of PIM parts

The factors affecting the dimensional tolerance of powder injection molding (PIM), such as the selection of the powder and binder, the feedstock homogeneity, the feedstock thermal properties, the feedstock rheologic behavior, the debinding schedule and atmosphere and sintering temperature gradient were discussed. An attempt was made to develop a model to estimate the influence of important variables. The results show that a better understanding of these factors can provide some useful theoretical instructions for large scale production.

Diagnosis of the Medium-Range Variation of the Subtropical High over the Western Pacific during a Meiyu Process by Three-Dimensional E-P Flux

In this paper, using the daily grid data (2.5 × 2.5) of the ECMWF / WMO, we have computed respectively the three-dimensional wave activity flux in the stages of pre-onset, prevailing and post ending of Meiyu from 1 to 31 July 1982. The potential vorticity field is taken as the physical quantity relating the wave activity flux to the variation of the subtropical high over the Western Pacific. It is found that the three-dimensional wave activity flux is a powerful means for diagnosis of the variation of the subtropical high over the Western Pacific: The region of the subtropical high is just the confluence area of wave energy, whose changes in intensity and range decide the variation of the subtropical high. The confluence of wave energy comes from the monsoon flow in low latitudes, the Meiyu rain belts in middle latitudes and the heating fields on the eastern side of the Qinghai-Xizang Plateau. The relation between these sources and the subtropical high displays the self-adjusting mechanism among members of East-Asia summer monsoon.

Computer-Aided Process Tolerance Design

A comprehensive survey of the state of the art, the projection of future trends of process dimension charts and mathematical models in computer-aided process tolerance are presented In the paper.

Integration system research and development for three-dimensional laser scanning information visualization in goaf

An integration processing system of three-dimensional laser scanning information visualization in goaf was developed. It is provided with multiple functions, such as laser scanning information management for goaf, cloud data de-noising optimization, construction, display and operation of three-dimensional model, model editing, profile generation, calculation of goaf volume and roof area, Boolean calculation among models and interaction with the third party soft ware. Concerning this system with a concise interface, plentiful data input/output interfaces, it is featured with high integration, simple and convenient operations of applications. According to practice, in addition to being well-adapted, this system is favorably reliable and stable.

Active Fault Tolerant Control of a Class of Nonlinear Time-Delay Processes

Based on a nonlinear state predictor (NSP) and a strong tracking filter (STF), a sensor fault tolerant generic model control (FTGMC) approach for a class of nonlinear time-delay processes is proposed. First, the NSP is introduced, and it is used to extend the conventional generic model control (GMC) to nonlinear processes with large input time-delay. Then the STF is adopted to estimate process states and sensor bias, the estimated sensor bias is used to drive a fault detection logic. When a sensor fault is detected, the estimated process states by the STF will be used to construct the process output to form a 'soft sensor', which is then used by the NSP (instead of the real outputs) to provide state predictors. These procedures constitute an active fault tolerant control scheme. Finally, simulation results of a three-tank-system demonstrate the effectiveness of the proposed approach.

Three-dimensional visualization interactive system for digital twin workshop

To improve the human-physical-virtual coordination and integration of the digital twin workshop,3D visual monitoring and human-computer interaction of the digital twin workshop was studied.First,a novel 6D model of the 3D visualization interactive system for digital twin workshops is proposed.As the traditional 5D digital twin model ignores the importance of human-computer interaction,a new dimension of the user terminal was added.A hierarchical real-time data-driven mapping model for the workshop production process is then proposed.Moreover,a real-time data acquisition method for the industrial Internet of things is proposed based on OPC UA(object linking and embedding for process control unified architecture).Based on the 6D model of the system,the process of creating a 3D visualization virtual environment based on virtual reality is introduced,in addition to a data-driven process based on the data management cloud platform.Finally,the 6D model of the system was confirmed using the blade rotor test workshop as the object,and a 3D visualization interactive system is developed.The results show that the system is more transparent,real-time,data-driven and more efficient,as well as promotes the coordination and integration of human-physical-virtual,which has practical significance for developing digital twin workshops.

Radiation Tolerant Viterbi Decoders for On-Board Processing(OBP) in Satellite Communications

Modern satellite communication systems require on-board processing(OBP)for performance improvements,and SRAM-FPGAs are an attractive option for OBP implementation.However,SRAM-FPGAs are sensitive to radiation effects,among which single event upsets(SEUs)are important as they can lead to data corruption and system failure.This paper studies the fault tolerance capability of a SRAM-FPGA implemented Viterbi decoder to SEUs on the user memory.Analysis and fault injection experiments are conducted to verify that over 97%of the SEUs on user memory would not lead to output errors.To achieve a better reliability,selective protection schemes are then proposed to further improve the reliability of the decoder to SEUs on user memory with very small overhead.Although the results are obtained for a specific FPGA implementation,the developed reliability estimation model and the general conclusions still hold for other implementations.

Three-dimensional coordinates test method with uncertain projectile proximity explosion position based on dynamic seven photoelectric detection screen

To objectively obtain the three-dimensional coordinates of the projectile fuze proximity explosion when projectile intersects the head of missile target, we propose a dynamic seven photoelectric detection screen test method, which is made up of six plane detection screens and a flash photoelectric dynamic detection screen. The three-dimensional coordinates calculation model of the projectile proximity explosion position based on seven plane detection screens with dynamic characteristics is established.According to the relation of the dynamic seven photoelectric detection screen planes and the time values,the analytical function of the projectile proximity explosion position parameters under non-linear motion is derived. The projectile signal filtering method based on discrete wavelet transform is explored in this work. Additionally, the projectile signal recognition algorithm using an improved particle swarm is proposed. Based on the characteristics of the time duration and the signal peak error for the projectile passing through the detection screen, the signals attribution of the same projectile passing through six detection screens are analyzed for obtaining precise time values of the same projectile passing through the detection screens. On the basis of the projectile fuze proximity explosion test, the linear motion model and the proposed non-linear motion model are used to calculate and compare the same group of projectiles proximity explosion position parameters. The comparison of test results verifies that the proposed test method and calculation model in this work accurately obtain the actual projectile proximity explosion position parameters.

Three-Dimensional Model Reconstruction of Nonwovens from Multi-Focus Images

The three-dimensional(3D)model is of great significance to analyze the performance of nonwovens.However,the existing modelling methods could not reconstruct the 3D structure of nonwovens at low cost.A new method based on deep learning was proposed to reconstruct 3D models of nonwovens from multi-focus images.A convolutional neural network was trained to extract clear fibers from sequence images.Image processing algorithms were used to obtain the radius,the central axis,and depth information of fibers from the extraction results.Based on this information,3D models were built in 3D space.Furthermore,self-developed algorithms optimized the central axis and depth of fibers,which made fibers more realistic and continuous.The method with lower cost could reconstruct 3D models of nonwovens conveniently.

Three-Dimensional Measurement and Reconstruction of Fabric Drape Shape

This paper introduces a new method of measuring the three-dimensional drape shape of fabrics with structural light. First, we apply parallel annular structural light to form light and shade alternating contour stripes on the surface of fabrics. We then collect the images of contour stripes using Charge Coupled Device (CCD). Subsequently, we process the images to identify the contour stripes and edges of fabrics, and obtain the fabric contour lines of curved surfaces. Finally, we apply three-dimensional curved surface modeling method based on a network of polar coordinates, and reconstruct the three-dimensional drape shape of fabrics. Experiments show that our method is effective in testing and reconstructing three-dimensional drape shape of fabrics.

G-protein β subunit AGB1 positively regulates salt stress tolerance in Arabidopsis

The heterotrimeric GTP-binding proteins（G-proteins） in eukaryotes consisted of α, β and γ subunits and are important in molecular signaling by interacting with G-protein-coupled receptors（GPCR）, on which to transduce signaling into the cytoplast through appropriate downstream effectors. However, downstream effectors regulated by the G-proteins in plants are currently not well defined. In this study, the transcripts of AGB1, a G protein β subunit gene in Arabidopsis were found to be down-regulated by cold and heat, but up-regulated by high salt stress treatment. AGB1 mutant（agb1-2） was more sensitive to high salt stress than wild-type（WT）. Compared with WT, the cotyledon greening rates, fresh weight, root length, seedling germination rates and survival rates decreased more rapidly in agb1-2 along with increasing concentrations of Na Cl in normal（MS） medium. Physiological characteristic analysis showed that compared to WT, the contents of chlorophyll, relative proline accumulation and peroxidase（POD） were reduced, whereas the malonaldehyde（MDA） content and concentration ratio of Na＋/K＋ were increased in agb1-2 under salt stress condition. Further studies on the expression of several stress inducible genes associated with above physiological processes were investigated, and the results revealed that the expressions of genes related to proline biosynthesis, oxidative stress response, Na＋ homeostasis, stress- and ABAresponses were lower in agb1-2 than in WT, suggesting that those genes are possible downstream genes of AGB1 and that their changed expression plays an important role in determining phenotypic and physiologic traits in agb1-2. Taken together, these findings indicate that AGB1 positively regulates salt tolerance in Arabidopsis through its modulation of genes transcription related to proline biosynthesis, oxidative stress, ion homeostasis, stress- and ABA-responses.

Effect of Inorganic Salts on the Thermotolerance and Probiotic Properties of Lactobacilli Isolated from Curdled Milk Traditionally Produced in Mezam Division, Cameroon

The industrial production of most food and probiotic products often requires processing involving high temperatures and physiological stress causing loss of viability of probiotic microbial strains. The viability and stability of probiotic strains is a key determinant of their efficacy during administration in human and animal. Thermotolerance is actually a very important feature for probiotic undergoing industrial processing. This paper aimed at assessing the effect of some mineral salts on the thermotolerance and the probiotic properties of lactobacilli isolated from curded milk produced in Mezam Division, Cameroon. Lactobacilli were isolated by pour plate method on de Man Rogosa and Sharpe (MRS) agar. Lactobacilli were selected based on their ability to suppress in-vitro and in-vivo food borne pathogenic bacteria;Salmonella enterica serovar Enteridis and Esherichia coli. Inhibitory activities against these food borne pathogens were performed by disc diffusion method on Mueller Hinton agar. In-vivo inhibition of Salmonella was achieved using oral administration by gavage of (1.0 × 109 CFU/ml) of selected probiotic strain suspended in sterile water. Thermotolerance was assessed by measuring the survival rate of the strain after heating at various temperatures in the presence and absence of mineral salts. Resistance to bile was determined by measuring the survival rate of probiotics after incubation in the presence of oxgallbille and mineral salts. Two catalase negatives isolates were selected based on their capacity to exhibit inhibitory activities in-vitro and in-vivo against food borne pathogens. They were identified as strain of Lactobacillus casei (LS3) and Lactobacillus plantarum (LM4). These strains exhibited significant reduction (P Salmonella count in caeca swabs of infected chick model. The calcium and magnesium salts increased significantly (P < 0.05) the thermo-tolerance and resistance to bile of probiotic strains studied. These results suggested that calcium and magnesium could be used to monitor the viability of probiotic strains in probiotic products.

复配乳化剂加工耐受性研究及在奶茶中的应用

文章研究了单双甘油酯、琥珀酸单甘油酯和酪蛋白酸钠复配乳化剂方案和瓶装奶茶常用乳化剂方案在饮料加工过程中耐受离子、剪切、温度等不利因素的能力及在奶茶中的应用。通过粒度分析仪评估不同方案乳化剂在加工不利因素下的乳化稳定性;以Turbiscan、Lumisizer稳定性扫描结果结合离心脂肪上浮和货架期放置观察情况,评估不同乳化剂方案稳定奶茶中油脂的效果。结果表明:单双甘油酯、琥珀酸单甘油酯和酪蛋白酸钠以3∶4∶10比例复配,对椰子油有很好的乳化效果,可以将椰子油平均粒径降到0.21μm左右,且对离子、剪切、温度等条件的耐受性强;该复配方案应用到奶茶,仅需添加油脂总量的0.40%,就能将奶茶平均粒径降至0.3μm左右,且加工前后粒径无差异。由此可知:该研究结果不仅能够大幅度降低乳化剂用量、节约生产成本,而且可以提高乳化剂的加工耐受性,对最大限度发挥乳化剂的作用、提升产品品质、提高产品质量稳定性具有重要的意义,为高效、科学、规范使用食品乳化剂也具有一定的指导作用。