bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Calcium Carbide Residue on Strength Development along with Mechanisms of Cement-Stabilized Dredged Sludge
Authors: Zhu Xinyi , Niu Fujun , Ren Lu , Jiao Chenglong , Jiang Haiqiang , Yao Xiaoyue
Published: June 2022

The purpose of this research is to explore the feasibility of using calcium carbide residue (CCR), a by-product from acetylene gas production, as a solid alkaline activator on the strength development in CCR–Portland cement-stabilized dredged sludge (CPDS). The effects of cement content, CCR content and curing time on the strength development of CPDS were investigated using a series of unconfined compressive strength (UCS), pH and electric conductivity (EC) tests. Scanning electron microscopy and X-ray diffraction analyses were performed to gain additional insight into the mechanism of strength development. Meanwhile, the carbon footprints of CPDS were calculated. Following the results, it was found that CCR can significantly improve the strength of cemented dredged sludge. On the basis of the strength difference (ΔUCS) and strength growth rate (UCSgr), it was recommended that utilizing 20% cement with the addition of 20% CCR is the most effective way to develop the long-term strength of CPDS. In addition, the microstructural analysis verified that the optimum proportion of CCR benefits the formation of hydration products in CPDS, particularly needle-like gel ettringite, resulting in a less-porous and dense inter-locked structure. Furthermore, the solidification mechanism of CPDS was discussed and revealed. Finally, it was confirmed that CCR can be a sustainable alternative and effective green alkaline activator for the aim of improving cemented dredged sludge.
Numerical Parametric Study of Coda Wave Interferometry Sensitivity to Microcrack Change in a Multiple Scattering Medium
Authors: Ma Bin , Liu Shukui , Ma Zhanguo , Wang Qi-Ang , Yu Zibo
Published: June 2022

The expansion of cracks in 3D printing concrete materials may lead to structural failure, so it is essential to monitor crack propagation development. Coda wave interferometry (CWI) has been proven to be sensitive to microcracks, however, the evolution pattern of ultrasonic coda waves during crack growth is still not clear. This paper reports a numerical study of the sensitivity and feasibility of CWI for monitoring microcrack growth in heterogeneous materials. A two-phase concrete model, which contains microcracks with different angles and lengths, was developed using the finite element analysis software ABAQUS. The relative velocity change (Δv/v) and the decorrelation coefficient (Kd) at different crack increments were quantitatively analyzed. The numerical simulation results show that coda waves are sensitive to microcrack length as well as the crack angle. The Δv/v increases linearly with the increase of the length of a single microcrack, and the Kd could be linked to the crack length quadratically. Furthermore, a quantitative functional relationship between the CWI observations (Kd, Δv/v) and the angle of the crack to the source/receiver and the relative length growth of the crack are established. In addition, the nonlinear relationship between slope and angle can be fitted with a sinusoidal function. The reported results quantitatively assess the coda wave variation pattern during crack propagation, which is important for the promotion and application of CWI technology.
Compatibility of Different Commercial Alloys in High-Temperature, Supercritical Carbon Dioxide
Authors: Zhang Gen , Jiang E , Liu Weiwei , Yang Hong , Wu Yulong , Huang Yanping
Published: June 2022

In this work, the compatibility and long-term integrity of candidate structural materials, including the austenitic stainless steel 316NG, the Fe-Ni-based alloy 800H, and the Ni-based alloy 625, were tested in high-temperature and high-pressure SCO2. The exposure time was up to 3000 h. The results showed that the corrosion kinetics approximately followed a near-cubic law for 316NG and 800H. After 3000 h exposure, all oxide layers, mainly composed of Cr2O3, were continuous, compact, and protective, and their thicknesses were about 21~45 nm, 64~88 nm, and 34~43 nm, respectively. In the case of carburization, dark spots corresponding carbon deposition were observed on the surface and a little enriched in the underside of the oxide for 800H. Moreover, the enrichment of trace elements was found at the oxide/substrate interface through GDOES and TEM analyses, i.e., the enrichment of Mn and Si for 316NG, the enrichment of Mn, Si, Al, and Ti for 800H, and the enrichment of Ti and Al for alloy 625.
Pyrolysis Characteristics and Non-Isothermal Kinetics of Integrated Circuits
Authors: Chen Ziwei , Liu Linhao , Wang Hao , Liu Lili , Wang Xidong
Published: June 2022

Due to the complexity of components and high hazard of emissions, thermochemical conversions of plastics among waste-integrated circuits (ICs) are more favorable compared with the common treatment options of electronic waste (E-waste), such as chemical treatment and burning. In this study, the waste random-access memory, as the representative IC, was used to investigate the thermal degradation behaviors of this type of E-waste, including a quantitative analysis of pyrolysis characteristics and non-isothermal kinetics. The results show that the pyrolysis of the ICs can be divided into three different decomposition stages. The pyrolysis temperature and gas atmosphere play an important role in the pyrolysis reaction, and the heating rate greatly affects the rate of the pyrolysis reaction. The non-isothermal kinetic parameters and reaction mechanisms of ICs are determined using the Friedman method, Coats and Redfern (CR) method, and Kissinger method. The results show that the actual average activation energy of the pyrolysis reaction of ICs should be between 170 and 200 kJ·mol−1. The optimally fitting model for the ICs pyrolysis is the three-step parallel model consisting of the random nucleation model (Am) and reaction order model (Cn).
Effects of Processing Parameters on the Microstructure and Mechanical Properties of Nanoscaled WC-10Co Cemented Carbide
Authors: Wang Yu , Xiang Fengming , Yuan Xiaobo , Yang Biaobiao , Wang Fenglin , Li Yunping
Published: June 2022

This work was mainly focused on the processing-parameter-related microstructure and properties of ultrafine WC-10Co-0.4VC-0.5Cr3C2 cemented carbide. The samples were prepared via a spark plasma sintering (SPS) technique using nano WC and Co powders and the corresponding inhibitor VC and Cr3C2 powders. The influence of the processing process on the microstructure and mechanical properties of ultrafine-grained cemented carbide was investigated under different ball-milling times and sintering temperatures. The results showed that the grain size of WC decreased with increasing ball-milling time and decreasing sintering temperature and that the specific gravity of ε-Co increased with increasing ball-milling time. The hardness of cemented carbide increased with increasing ball-milling time and decreased with increasing sintering temperature due to the corresponding variation in grain size and the relative density of samples. The transverse fracture strength (TRS) was mainly affected by ball-milling time. The increase in ball-milling time led to decreased TRS values, mainly ascribed to the formation of WC particle agglomeration and the decreased WC-Co eutectic temperature. In addition, temperature changes were found to have little effect on TRS. The samples sintered at 1250 °C with a ball-milling time of 60 h had comprehensive mechanical properties. Their average grain size, relative density, hardness, and TRS were 355.5 nm, 95.79%, 2035.5 kg/mm2, and 2155.99 MPa, respectively.
Fatigue Cracking Evolution and Model of Cold Recycled Asphalt Mixtures during Different Curing Times
Authors: Xia Yu , Lin Juntao , Chen Zongwu , Cai Jun , Hong Jinxiang , Zhu Xiaobin
Published: June 2022

This paper aims to investigate the fatigue cracking evolution of cold recycled asphalt mixtures with asphalt emulsion (CRME) under different curing times. The fatigue cracking model of CRME based on damage mechanics and fracture mechanics was analyzed according to the fatigue loading curve. Firstly, the fatigue cracking evolution of CRME was studied through an SCB strength test and SCB fatigue test. Then, the fatigue damage mechanics were used to establish a nonlinear fatigue cracking model, and the damage degree of CRME at the initial cracking point was determined. The Paris formula was used to characterize the law of fatigue crack propagation. Finally, the microstructure of CRME was observed by scanning electron microscopy (SEM) with the backscattering method. The results indicate that the initial cracking point appears at around 60% of the fatigue life according to the SCB fatigue test by means of image analysis. The damage variable was obtained through the cracking model, and the value of the damage variable was determined as 0.06–0.17 at the initial cracking point. In addition, the Paris formula showed that the crack growth of CRME can be reflected by the stress intensity factor and correlative parameters. Moreover, cement hydration products were mixed with the asphalt membrane to form a denser spatial structure during the curing process, which may provide higher fatigue performance of CRME. This research may provide a theoretical reference for studying the fatigue cracking behavior of CRME.
Experimental Investigation of the Mechanical Properties of the Sand–Concrete Pile Interface Considering Roughness and Relative Density
Authors: Chen Chen , Yang Qi , Leng Wuming , Dong Junli , Xu Fang , Wei Limin , Ruan Bo
Published: June 2022

The aim of this study was to investigate the effect of roughness and relative density on the mechanical properties of sand–concrete pile interface. A series of direct shear tests were carried out on the interface using a large-scale direct shear apparatus with various relative densities of sand (73%, 47%, and 23%) and concrete blocks with four roughness values (I = 0, 10, 20, and 30 mm). Various mechanical properties (such as shear stress, volume change, peak shear strength, secant friction angle, and normalized friction coefficient) from the interface tests were compared with trends obtained from the pure sand direct shear test. For the smooth interface, the shear stress–horizontal displacement curves of the dense sand specimen exhibited a slight softening response, which became more apparent as the roughness increased. The curves of the loose sand specimen demonstrated a hardening response. The volumetric response was influenced by the combination of normal stress, relative density, and roughness. The peak shear strength demonstrated a nonlinear increasing trend as the normal stress increased. With an increase in the normal stress, the secant friction angle and peak friction coefficient decreased as exponential and power functions, respectively. Additionally, a critical roughness value Icr resulted from the tests, which halted the upward trend of the peak friction coefficient and normalized the secant friction angle when I exceeded Icr.
Conversion of Short and Medium Chain Fatty Acids into Novel Polyhydroxyalkanoates Copolymers by Aeromonas sp. AC_01
Authors: Szacherska Karolina , Moraczewski Krzysztof , Czaplicki Sylwester , Oleskowicz-Popiel Piotr , Mozejko-Ciesielska Justyna
Published: June 2022

Polyhydroxyalkanoates (PHAs) production by Aeromonas sp. AC_01 was investigated using synthetic and waste derived short and medium chain fatty acids (SMCFAs). The obtained results revealed that the analyzed bacterial strain was able to grow and synthesize PHAs using SMCFAs. The highest PHA productivity was observed in the cultivation supplemented with a mixture of acetic acid and butyric acid (3.89 mg/L·h). Furthermore, SMCFAs-rich stream, derived from acidogenic mixed culture fermentation of acid whey, was found to be less beneficial for PHA productivity than its synthetic mixture, however the PHA production was favored by the nitrogen-limited condition. Importantly, Aeromonas sp. AC_01 was capable of synthesizing novel scl-mcl copolymers of 3-hydroxybutyrate (3HB), 3-hydroxyvalerate (3HV), 3-hydroxytridecanoate (3HtriD) and/or 3-hydroxytetradecaonate (3HTD) with high 3HB and 3HV fractions. They were identified with alterable monomers composition depending on the culture conditions used. Moreover, in-depth thermal analyses proved that they are highly resistant to thermal degradation regardless of their monomeric composition. The obtained results confirm that Aeromonas sp. AC_01 is a promising candidate for the biotechnological production of PHAs from SMCFAs with thermal properties that can be tuned together with their chemical composition by the corresponding adjustment of the cultivation process.
A Hybrid Level Set Method for the Topology Optimization of Functionally Graded Structures
Authors: Fu Junjian , Shu Zhengtao , Gao Liang , Zhou Xiangman
Published: June 2022

This paper presents a hybrid level set method (HLSM) to design novelty functionally graded structures (FGSs) with complex macroscopic graded patterns. The hybrid level set function (HLSF) is constructed to parametrically model the macro unit cells by introducing the affine concept of convex optimization theory. The global weight coefficients on macro unit cell nodes and the local weight coefficients within the macro unit cell are defined as master and slave design variables, respectively. The local design variables are interpolated by the global design variables to guarantee the C0 continuity of neighboring unit cells. A HLSM-based topology optimization model for the FGSs is established to maximize structural stiffness. The optimization model is solved by the optimality criteria (OC) algorithm. Two typical FGSs design problems are investigated, including thin-walled stiffened structures (TWSSs) and functionally graded cellular structures (FGCSs). In addition, additively manufactured FGCSs with different core layers are tested for bending performance. Numerical examples show that the HLSM is effective for designing FGSs like TWSSs and FGCSs. The bending tests prove that FGSs designed using HLSM are have a high performance.
Comparative Analysis of Reconfigurable Platforms for Memristor Emulation
Authors: Mayacela Margarita , Rentería Leonardo , Contreras Luis , Medina Santiago
Published: June 2022

The memristor is the fourth fundamental element in the electronic circuit field, whose memory and resistance properties make it unique. Although there are no electronic solutions based on the memristor, interest in application development has increased significantly. Nevertheless, there are only numerical Matlab or Spice models that can be used for simulating memristor systems, and designing is limited to using memristor emulators only. A memristor emulator is an electronic circuit that mimics a memristor. In this way, a research approach is to build discrete-component emulators of memristors for its study without using the actual models. In this work, two reconfigurable hardware architectures have been proposed for use in the prototyping of a non-linearity memristor emulator: the FPAA (Field Programing Analog Arrays) and the FPGA (Field Programming Gate Array). The easy programming and reprogramming of the first architecture and the performance, high area density, and parallelism of the second one allow the implementation of this type of system. In addition, a detailed comparison is shown to underline the main differences between the two approaches. These platforms could be used in more complex analog and/or digital systems, such as neural networks, CNN, digital circuits, etc.
Microstructural Variations in Laser Powder Bed Fused Al–15%Fe Alloy at Intermediate Temperatures
Authors: Wang Wenyuan , Takata Naoki , Suzuki Asuka , Kobashi Makoto , Kato Masaki
Published: June 2022

The samples of the Al–15Fe (mass%) binary alloy that were additively manufactured by laser powder bed fusion (L-PBF) were exposed to intermediate temperatures (300 and 500 °C), and the thermally induced variations in their microstructural characteristics were investigated. The L-PBF-manufactured sample was found to have a microstructure comprising a stable θ-Al13Fe4 phase localized around melt-pool boundaries and several spherical metastable Al6Fe-phase particles surrounded by a nanoscale α-Al/Al6Fe cellular structure in the melt pools. The morphology of the θ phase remained almost unchanged even after 1000 h of exposure at 300 °C. Moreover, the nanoscale α-Al/Al6Fe cellular structure dissolved in the α-Al matrix; this was followed by the growth (and nucleation) of the spherical Al6Fe-phase particles and the precipitation of the θ phase. Numerous equiaxed grains were formed in the α-Al matrix during the thermal exposure, which led to the formation of a relatively homogenous microstructure. The variations in these microstructural characteristics were more pronounced at the higher investigated temperature of 500 °C.
Titanium-Pillared Clay: Preparation Optimization, Characterization, and Artificial Neural Network Modeling
Authors: Mosavi Mirak Seyed Heydar , Sharifian Seyedmehdi , Esmaeili Khalil Saraei Fatemeh , Asasian-Kolur Neda , Haddadi Bahram , Jordan Christian , Harasek Michael
Published: June 2022

Titanium-pillared clay (Ti-PILC), as one of the most suitable types of porous adsorbents/(photo)catalysts, was prepared from a local type of Iranian clay and titanium isopropoxide. The production process was optimized by changing three operating parameters, including the clay suspension concentration (in the range of 0.5–10% w/v), the H+/Ti ratio (2–8 mol/mol), and the calcination temperature (300–700 °C). The largest specific surface area for the Ti-PILC was about 164 m2/g under the clay suspension of 0.5% w/v, H+/Ti = 6, with a surface area 273% larger than that of the raw clay. The surface areas obtained from more concentrated clay suspensions were, however, comparable (159 m2/g for 3% w/v clay and H+/Ti = 4). An increase in the calcination temperature has a negative effect on the porous texture of Ti-PILC, but based on modeling with artificial neural networks, its contribution was only 7%. Clay suspension and H+/Ti ratio play a role of 56 and 37% of the specific surface area. The presence of rutile phase, and in some cases anatase phase of TiO2 crystals was detected. FTIR and SEM investigations of Ti-PILCs produced under different operating parameters were analyzed.
A Three-Dimensional Transition Interface Model for Bolt Joint
Authors: Lei Sheng , Mao Kuanmin , Tian Wei , Li Li
Published: June 2022

Bolt connection is an important component in mechanical structure which significantly affects the dynamic property of the whole structure. In this paper, a three-dimensional transition interface model which contains geometric and physical parameters is proposed to model the bolted joint based on the contact analysis. The geometric parameters and the physical parameters are used to characterize the influence of contact area and contact pressure which are related to connection parameters such as material, roughness, connection thickness, and tightening force, respectively. After that, the geometric parameter identification method is proposed, and the geometric parameter database of bolt joints for machine tools is constructed based on the Kriging interpolation method. Then, the model updating method based on the combination of modal parameters and frequency response function is proposed to identify the physical parameters and thickness of the three-dimensional transition interface model. The database of the transition interface model is constructed after verifying the validity of the proposed model. Finally, an engineering example of an engraving machine tool is used to check the practicability of the proposed transition interface model and the usage of the constructed parameter database.
Hybrid Force and Motion Control of a Three-Dimensional Flexible Robot Considering Measurement Noises
Authors: Kilicaslan Sinan , Özgören Mustafa Kemal , Ider Sıtkı Kemal
Published: June 2022

This work addresses the end-effector trajectory-tracking force and motion control of a three-dimensional three-link robot considering measurement noises. The last two links of the manipulator are considered as structurally flexible. An absolute coordinate approach is used while obtaining the dynamic equations to avoid complex dynamic equations. In this approach, each link is modeled as if there is no connection between the links. Then, joint connections are expressed as constraint equations. After that, these constraint equations are used in dynamic equations to decrease the number of equations. Then, the resulting dynamic equations are transformed into a form which is suitable for controller design. Furthermore, the dynamic equations are divided as pseudostatic equilibrium and deviation equations. The control torques resulting from the pseudostatic equilibrium and the elastic deflections are obtained easily as the solution of algebraic equations. On the other hand, the control torques corresponding to the deviations are obtained without any linearization. Encoders, strain gauges, position sensors and force and moment sensors are required for measurements. Low pass filters are considered for the sensors. For the crossover frequencies of the sensors, low and high values are chosen to observe the filtering effect on the robot output.
Semi-Supervised Transfer Learning Method for Bearing Fault Diagnosis with Imbalanced Data
Authors: Zong Xia , Yang Rui , Wang Hongshu , Du Minghao , You Pengfei , Wang Su , Su Hao
Published: June 2022

Fault diagnosis is essential for assuring the safety and dependability of rotating machinery systems. Several emerging techniques, especially artificial intelligence-based technologies, are used to overcome the difficulties in this field. In most engineering scenarios, machines perform in normal conditions, which implies that fault data may be hard to acquire and limited. Therefore, the data imbalance and the deficiency of labels are practical challenges in the fault diagnosis of machinery bearings. Among the mainstream methods, transfer learning-based fault diagnosis is highly effective, as it transfers the results of previous studies and integrates existing resources. The knowledge from the source domain is transferred via Domain Adversarial Training of Neural Networks (DANN) while the dataset of the target domain is partially labeled. A semi-supervised framework based on uncertainty-aware pseudo-label selection (UPS) is adopted in parallel to improve the model performance by utilizing abundant unlabeled data. Through experiments on two bearing datasets, the accuracy of bearing fault classification surpassed the independent approaches.
Microstructure and Magnetic Properties of M-Type Sr0.1Ca0.4La0.5Fe12O19 Ferrites: The Impact of Different Precursors
Authors: Zhao Xiubin , Zhang Shuang , Li Jinsong , Xia Ailin , Yang Yujie
Published: June 2022

M-type Sr0.1Ca0.4La0.5Fe12O19 powder specimens doped with different precursors RFe2O4(R = Co, Ni, Cu, Zn, and Mg) were prepared via a traditional solid-state reaction method. The structural and magnetic properties of the specimens were studied. Only nthe single magnetoplumbite phase was found in all the specimens with uniformly distributed particles. The specimen with Zn-type precursor has the highest saturation (Ms), while the specimen with Co-type precursor has the highest remanent magnetism (Mr), coercivity (Hc), and the best comprehensive magnetic properties.
Temperature Trend Analysis and Investigation on a Case of Variability Climate
Authors: Monforte Pietro , Ragusa Maria Alessandra
Published: June 2022

Climate change is now evident on a global scale. In some regions, the phenomenon is especially amplified, generating different consequences for man and the environment. Sicily is one of the Mediterranean regions, the biggest in terms of area, where climatic variations produce significant effects. In this study, temperature trends on monthly time scales are examined in the time frame 1925–2015. The cluster analysis technique (Ward’s method) was used to homogenize the temperature series. The results show four statistically significant clusters, confirming the presence of climatic variability in the region. The non-parametric Mann–Kendall test was used to determine temperature trends. The non-parametric estimator Sen’s slope was used to quantify the variation of trends. The results showed the presence of statistically significant trends. A worrying and unexpected increase in temperatures was found during the winter period. This scenario was presented in three clusters, highlighting a mutation in the winter season, attributable to the climatic changes in progress rather than to territorial factors. If the trends maintain an increasing monotone character, in the coming decades there will be, in many areas of Sicily, a constant loss of fertile soil for the agricultural sector and the advancement of phenomena such as drought and desertification, to which the island is already predisposed. All of this will have serious socio-economic repercussions. Considering that a large part of the region’s economy is based on the agricultural sector, these repercussions will be followed by serious environmental implications that will negatively affect the ecological sustainability of the region.
An Artificial Bee Colony Algorithm for Static and Dynamic Capacitated Arc Routing Problems
Authors: Nagy Zsuzsanna , Werner-Stark Ágnes , Dulai Tibor
Published: June 2022

The Capacitated Arc Routing Problem (CARP) is a combinatorial optimization problem, which requires the identification of such route plans on a given graph to a number of vehicles that generates the least total cost. The Dynamic CARP (DCARP) is a variation of the CARP that considers dynamic changes in the problem. The Artificial Bee Colony (ABC) algorithm is an evolutionary optimization algorithm that was proven to be able to provide better performance than many other evolutionary algorithms, but it was not used for the CARP before. For this reason, in this study, an ABC algorithm for the CARP (CARP-ABC) was developed along with a new move operator for the CARP, the sub-route plan operator. The CARP-ABC algorithm was tested both as a CARP and a DCARP solver, then its performance was compared with other existing algorithms. The results showed that it excels in finding a relatively good quality solution in a short amount of time, which makes it a competitive solution. The efficiency of the sub-route plan operator was also tested and the results showed that it is more likely to find better solutions than other operators.
A Novel Fractional-Order Discrete SIR Model for Predicting COVID-19 Behavior
Authors: Djenina Noureddine , Ouannas Adel , Batiha Iqbal M. , Grassi Giuseppe , Oussaeif Taki-Eddine , Momani Shaher
Published: June 2022

During the broadcast of Coronavirus across the globe, many mathematicians made several mathematical models. This was, of course, in order to understand the forecast and behavior of this epidemic’s spread precisely. Nevertheless, due to the lack of much information about it, the application of many models has become difficult in reality and sometimes impossible, unlike the simple SIR model. In this work, a simple, novel fractional-order discrete model is proposed in order to study the behavior of the COVID-19 epidemic. Such a model has shown its ability to adapt to the periodic change in the number of infections. The existence and uniqueness of the solution for the proposed model are examined with the help of the Picard Lindelöf method. Some theoretical results are established in view of the connection between the stability of the fixed points of this model and the basic reproduction number. Several numerical simulations are performed to verify the gained results.
A Bivariate Optimal Random Replacement Model for the Warranted Product with Job Cycles
Authors: Shang Lijun , Du Yongjun , Wu Cang , Ma Chengye
Published: June 2022

A monitoring system (MS) has been used to monitor products’ job cycles. It is indicated that by incorporating the job cycle into the product’s life cycle, warrantors can devise novel warranty models and consumers can define and model random maintenances sustaining the reliability of the product through warranty. In this study, by incorporating limited job cycles and a refund into the traditional free repair warranty, a two-dimensional free repair warranty with a refund (2DFRW-R) is devised for guaranteeing the product reliability to consumers. Under the condition that 2DFRW-R is planned to guarantee product reliability, a bivariate random periodic replacement (BRPR) (i.e., a random periodic replacement where the accomplishment of the Nth job cycle and the replacement time T are designed as replacement limits) is modeled to sustain the post-warranty reliability from the point of view of the consumer. From the point of view of the warrantor, the warranty cost related to 2DFRW-R is derived, and the characteristics of 2DFRW-R are explored. From the point of view of consumers, the expected cost rate related to BRPR is constructed, and the existence and uniqueness of the optimal BRPR are summarized as well. By discussing parameters, several special cases are derived. The characteristics of the proposed models are analyzed in numerical examples.
Group Logistic Regression Models with lp,q Regularization
Authors: Zhang Yanfang , Wei Chuanhua , Liu Xiaolin
Published: June 2022

In this paper, we proposed a logistic regression model with lp,q regularization that could give a group sparse solution. The model could be applied to variable-selection problems with sparse group structures. In the context of big data, the solutions for practical problems are often group sparse, so it is necessary to study this kind of model. We defined the model from three perspectives: theoretical, algorithmic and numeric. From the theoretical perspective, by introducing the notion of the group restricted eigenvalue condition, we gave the oracle inequality, which was an important property for the variable-selection problems. The global recovery bound was also established for the logistic regression model with lp,q regularization. From the algorithmic perspective, we applied the well-known alternating direction method of multipliers (ADMM) algorithm to solve the model. The subproblems for the ADMM algorithm were solved effectively. From the numerical perspective, we performed experiments for simulated data and real data in the factor stock selection. We employed the ADMM algorithm that we presented in the paper to solve the model. The numerical results were also presented. We found that the model was effective in terms of variable selection and prediction.
Thread Algebra with Prospecting Services and Foresight Patterns
Authors: Bergstra Jan
Published: June 2022

Thread algebra is a domain-specific process algebra which may be used for semantic work on sequential systems, including systems based on deterministically scheduled multi-threading. Thread algebra is used in this capacity with the forecasting phenomenon for programs and machines as a domain of interest. Several new informal notions are proposed: prospecting services, foresight patterns for systems, and lookahead conditions as a mechanism for the specification of services. Some new prospecting services are proposed which facilitate the realisation of certain foresight patterns. Several negative results about the non-realisability of certain foresight patterns are provided.
Forecasting of Automobile Sales Based on Support Vector Regression Optimized by the Grey Wolf Optimizer Algorithm
Authors: Qu Fei , Wang Yi-Ting , Hou Wen-Hui , Zhou Xiao-Yu , Wang Xiao-Kang , Li Jun-Bo , Wang Jian-Qiang
Published: June 2022

With the development of the Internet and big data, more and more consumer behavior data are used in different forecasting problems, which greatly improve the performance of prediction. As the main travel tool, the sales of automobiles will change with the variations of the market and the external environment. Accurate prediction of automobile sales can not only help the dealers adjust their marketing plans dynamically but can also help the economy and the transportation sector make policy decisions. The automobile is a product with high value and high involvement, and its purchase decision can be affected by its own attributes, economy, policy and other factors. Furthermore, the sample data have the characteristics of various sources, great complexity and large volatility. Therefore, this paper uses the Support Vector Regression (SVR) model, which has global optimization, a simple structure, and strong generalization abilities and is suitable for multi-dimensional, small sample data to predict the monthly sales of automobiles. In addition, the parameters are optimized by the Grey Wolf Optimizer (GWO) algorithm to improve the prediction accuracy. First, the grey correlation analysis method is used to analyze and determine the factors that affect automobile sales. Second, it is used to build the GWO-SVR automobile sales prediction model. Third, the experimental analysis is carried out by using the data from Suteng and Kaluola in the Chinese car segment, and the proposed model is compared with the other four commonly used methods. The results show that the GWO-SVR model has the best performance of mean absolute percentage error (MAPE) and root mean square error (RMSE). Finally, some management implications are put forward for reference.
Non-Destructive Removal of Dental Implant by Using the Cryogenic Method
Authors: AK Burak , Eroğlu Emre Gürkan , Ertugrul Abdullah Seckin , Öztürk Ayla Batu , Yılmaz Şakir Necat
Published: June 2022

Background and Objectives: The gold standard for a successful prosthetic approach is the osseointegration of an implant. However, this integration can be a problem in cases where the implant needs to be removed. Removing the implant with minimal damage to the surrounding tissues is important. Osteocytes cannot survive below −2 °C, but epithelial cells, fibroblasts, and other surrounding tissue cells can. Remodeling can be triggered by cryotherapy at temperatures that specifically affect osteocyte necrosis. In this study, we aimed to develop a method for reversing the osseointegration mechanism and for protecting the surrounding tissues by bone remodeling induced by CO2 cryotherapy. Materials and Methods: In this study, eight 2.8 mm diameter, one-piece mini implants were used in New Zealand rabbit tibias. Two control and six implants were tested in this study. After 2 months of osseointegration, a reverse torque force method was used to remove all osseointegrated implants at 5, 10, 20, and 30 Ncm. The osseointegration of the implants was proven by periotest measurements. Changes in bone tissue were examined in histological sections stained with toluidine blue after rabbit sacrifice. The number of lacunae with osteocyte, empty lacunae, and lacunae greater than 5 µm and the osteon number in a 10,000 µm2 area were calculated. Cryotherapy was applied to the test implants for 1 min, 2 min, and 5 min. Three implants were subjected to cryotherapy at −40 °C, and the other implants were subjected to cryotherapy at −80 °C. Results: Empty lacunae, filled osteocytes, lacunae >5 µm, and the osteon count around the implant applied at −40 °C were not significantly different from the control implants. The application of −40 °C for 1 min was found to cause minimal damage to the bone cells. The implants, which were applied for 1 min and 2 min, were successfully explanted on the 2nd day with the 5 Ncm reverse torque method. Test implants, which were applied cold for 5 min, were explanted on day 1. Tissue damage was detected in all test groups at −80 °C. Conclusions: The method of removing implants with cryotherapy was found to be successful in −40 °C freeze–thaw cycles applied three times for 1 min. To prove implant removal with cryotherapy, more implant trials should be conducted.
SOCIUS Mentoring—A Novel Course to Encourage Students for a Career as Surgical Oncologists
Authors: Klapdor Rüdiger , Kleine Moritz , Schilling Tobias , Huusmann Stephan , Philippeit Anja , Philippeit Jill , Timrott Kai , Kruppa Marcus , Hillemanns Peter , Imkamp Florian
Published: June 2022

Surgical disciplines are affected by an increasing shortage of young doctors. Studies show that formerly interested students decide against a career in surgical disciplines at the end of their studies or during practical year. Measures to counteract this development are urgently needed. As a joint project between gynecology, urology, and general surgery, SOCIUS mentoring was designed to prepare and encourage students for a career in surgical oncology. The structured curriculum of SOCIUS mentoring contains six modules, including surgical skills, soft skills, mentoring, theory, clinical visitation, and congress participation and runs over one year. Effects on confidence towards physician skills and plans for a future career were evaluated with questionnaires. After participation, students reported increased confidence in surgical and soft skills. In addition, participants noted that they have specified their career goals and gained more confidence in surgery, as well as seeing more development potential for a career in surgery. We describe the implementation of a novel extracurricular program for motivated students that combines individual mentoring with surgical and soft skills training. Due to its modular structure, this concept can easily be transferred to other disciplines. SOCIUS mentoring, with its combination of mentoring and skills training, is a promising measure to prepare and motivate students for their surgical career and thus counteract the shortage of young talent.
Reconfigurable Measuring System for Quality Control of Cross-Wire Welding Group of Products
Authors: Vlatković Maja , Pavletić Duško , Ištoković David , Fabić Marko
Published: June 2022

Quality control of welded joint is an indispensable part of the welding production process. As part of spot resistance welding group, cross-wire welding process showed great application for welding of products for everyday usage. The non-contact quality control checking is fit for purpose due to specific characteristics of welded products that consist of two cross welded wires or a combination of wires and strips. This work proposes a new method for detecting and measuring of required dimensional parameters, but also founds its applicability for other products if required. A crucial parameter of this research is the height of welded joint, which is necessary for calculating the penetration of the wire into the wire. The proposed measuring method with a reconfigurable measuring system is explained in this paper. The main component of this system is using a machine vision system, which has become an indispensable part of industrial metrology and is considered one of the industry 4.0 concepts. The calibration process for such systems could be very complicated. This work shows an elaborated calibration procedure for this kind of measuring system with referenced standards made for this purpose. Measurement results are compared with ones obtained by conventional method. The focus of vision system is a substantial part as it dictates the quality of the system. This research is done within the project in collaboration with the industrial sector and all samples are from real processes. The results of measured penetration on one product group are showing the applicability of a reconfigurable measuring system in the welding sector, and demonstrate that measurement of welding penetration based on machine vision is feasible and can ensure accuracy.
Effect of Quenching and Tempering on Mechanical Properties and Impact Fracture Behavior of Low-Carbon Low-Alloy Steel
Authors: Zhang Yajing , Yang Jianhua , Xiao Daheng , Luo Deng , Tuo Chende , Wu Huibin
Published: June 2022

Conventional quenching and tempering were employed to achieve the optimal strength and toughness of low-carbon low-alloy steel. The fracture behavior (crack initiation and propagation) of the steel in the impact process was also analyzed. It was found that the microstructures of the steel after different tempering treatments were mainly composed of martensite, and its mechanical properties were dependent on the tempering temperature. With the increase in tempering temperature, martensitic laths merged and coarsened. Moreover, recovery occurred, causing a decrease in dislocation density. Subsequently, the strength of the steel gradually decreased, and the impact energy increased. When the tempering temperature was 600 °C, the optimal yield strength (557 MPa) and the impact energy (331 J) were achieved. In addition, high angle grain boundaries (HAGBs) affected the impact energy and crack propagation. Cracks were easily deflected when they encountered high angle grain boundaries, and linearly expanded when they encountered low angle grain boundaries (LAGBs).
Immune Optimization of Double-Sided Welding Sequence for Medium-Small Assemblies in Ships Based on Inherent Strain Method
Authors: Shen Yi , Liu Suodong , Yuan Mingxin , Dai Xianling , Lan Jinchun
Published: June 2022

The double-sided welding process is widely used in ship construction due to its high welding efficiency and forming quality. In order to further reduce the deformation caused by double-sided welding for medium-small assemblies in ships, the optimization of the double-sided welding sequence based on an artificial immune algorithm is carried out. First, the formation mechanism of welding deformation under the double-sided welding process is analyzed by the inherent strain method; next, the reduction of the welding deformation is taken as the optimization goal, and the welding sequence optimization model for double-sided welding is constructed; then, an immune clonal optimization algorithm based on similar antibody similarity screening and steady-state adjustment is introduced, and the immune optimization process for double-sided welding sequence is designed; finally, double-sided welding sequence optimization tests are carried out for four different types of medium-small assemblies in ships. Numerical test results show that, compared with IGA (Immune genetic algorithm), ICA (Immune clonal algorithm), and GA (Genetic algorithm), the maximum welding deformation caused by the welding sequence optimized by the proposed immune clonal algorithm is reduced by 2.4%, 2.8, and 3.3%, respectively, the average maximum welding deformation is reduced by 2.6%, 2.5, and 3.4%, respectively, and the convergence generation is reduced by 16.2%, 13.4, and 11.2%, respectively, which verifies the strong optimization ability and high optimization efficiency of the immune clonal algorithm introduced in the double-sided welding sequence optimization.
A Novel Fluidic Platform for Semi-Automated Cell Culture into Multiwell-like Bioreactors
Authors: Orecchio Francesca , Tommaso Vito , Santaniello Tommaso , Castiglioni Sara , Pezzotta Federico , Monti Andrea , Butera Francesco , Maier Jeanette , Milani Paolo
Published: June 2022

In this work, we developed and characterized a novel fluidic platform that enables long-term in vitro cell culture in a semi-automated fashion. The system is constituted by a control unit provided with a piezoelectric pump, miniaturized valves, and a microfluidic network for management and fine control of reagents’ flow, connected to a disposable polymeric culture unit resembling the traditional multiwell-like design. As a proof of principle, Human Umbilical Vein Endothelial Cells (HUVEC) and Human Mesenchymal Stem Cells (hMSC) were seeded and cultured into the cell culture unit. The proliferation rate of HUVEC and the osteogenic differentiation of hMSC were assessed and compared to standard culture in Petri dishes. The results obtained demonstrated that our approach is suitable to perform semi-automated cell culture protocols, minimizing the contribution of human operators and allowing the standardization and reproducibility of the procedures. We believe that the proposed system constitutes a promising solution for the realization of user-friendly automated control systems that will favor the standardization of cell culture processes for cell factories, drug testing, and biomedical research.
Piezoelectric MEMS Mirror with Lissajous Scanning for Automobile Adaptive Laser Headlights
Authors: Xu Bin , Ji Yao , Liu Kai , Li Jinhua
Published: June 2022

The emergence of smart headlights with reconfigurable light distributions that provide optimal illumination, highlight road objects, and project symbols to communicate with traffic participants further enhances road safety. Integrating all these functions in a single headlight usually suffers from issues of bulky multi-functional add-on modules with high cost or the use of conventional spatial light modulators with low optical efficiency and complex thermal design requirements. This paper presents a novel laser headlight prototype based on biaxially resonant microelectromechanical systems (MEMS) mirror light modulator for mapping blue laser patterns on phosphor plate to create structured white illumination and tunable road projection. The proposed headlight prototype system enables reconfigurable light distribution by leveraging laser beam scanning with fewer back-end lens and simple thermal design requirements. Built with thin-film lead zirconate titanate oxide (PbZrTiO3) actuators, the MEMS mirror achieved high-frequency biaxial resonance of 17.328 kHz, 4.81 kHz, and optical scan angle of 12.9°. The large mirror design of 2.0 mm facilitates more refined resolvable projection pixels, delivers more optical power, and provides moderate optical aperture to possibly serve as the common spatial light modulator of headlight and the light detection and ranging (LiDAR) towards all-in-one integration. The carefully designed bi-axial resonant frequency improves the device’s robustness by offsetting the lowest eigenmode away from the vehicle vibration. By establishing the laser headlight prototype systems of both 1D and 2D scanning modes, a mathematical model of laser modulation and MEMS electrical control principles of Lissajous scanning are proposed to tune the projection pattern density and shapes. It laid the foundation for developing a laser scanning control system with more complex project functions and prompting the application of MEMS for compact headlight system that addresses night driving visibility, eliminates glare effect, and renders interactive projection capabilities.
Optoelectronic Enhancement of Perovskite Solar Cells through the Incorporation of Plasmonic Particles
Authors: Mohamed Saheed Mohamed Salleh , Mohamed Norani Muti , Singh Balbir Singh Mahinder , Saheed Mohamed Shuaib Mohamed , Jose Rajan
Published: June 2022

The optoelectronic advantages of anchoring plasmonic silver and copper particles and non-plasmonic titanium particles onto zinc oxide (ZnO) nanoflower (NF) scaffolds for the fabrication of perovskite solar cells (PSCs) are addressed in this article. The metallic particles were sputter-deposited as a function of sputtering time to vary their size on solution-grown ZnO NFs on which methylammonium lead iodide perovskite was crystallized in a controlled environment. Optical absorption measurements showed impressive improvements in the light-harvesting efficiency (LHE) of the devices using silver nanoparticles and some concentrations of copper, whereas the LHE was relatively lower in devices used titanium than in a control device without any metallic particles. Fully functional PSCs were fabricated using the plasmonic and non-plasmonic metallic film-decorated ZnO NFs. Several fold enhancements in photoconversion efficiency were achieved in the silver-containing devices compared with the control device, which was accompanied by an increase in the photocurrent density, photovoltage, and fill factor. To understand the plasmonic effects in the photoanode, the LHE, photo-current density, photovoltage, photoluminescence, incident photon-to-current conversion efficiency, and electrochemical impedance properties were thoroughly investigated. This research showcases the efficacy of the addition of plasmonic particles onto photo anodes, which leads to improved light scattering, better charge separation, and reduced electron–hole recombination rate.