The signals of navigation satellites are easily affected by spoofing interference, causing the wrong position, speed or Universal Time Coordinate of the receiver to be calculated. Traditional detection and suppression algorithms are used only to eliminate the spoofing signals, which may lead to an insufficient number of satellites for positioning. An adaptive spoofing suppression algorithm (ASSA) based on a multiple antenna array is proposed in this study. The ASSA can use the cross-correlation gain of multiple antenna array to adaptively generate nulling and realize the simultaneous suppression of multiple spoofing signals. Moreover, ASSA does not need to capture and track spoofing separately, thus reducing the complexity of implementation and calculation. Experiments were conducted to verify the proposed system under different conditions, and the results show that ASSA can suppress multiple spoofings with little impact on positioning performance. Under the condition of spoofing, ASSAs were  in the static test and  in the kinematic test, which are good positioning performances for both. In addition, the ASSA is applied before capturing signals, which is beneficial to identifying and eliminating spoofing earlier and faster. Global satellite navigation systems (GNSSs) are widely used in civil aviation, transportation, power, finance and other fields . HoweverSignal processing algorithms have been studied as a means to detect spoofing interference. The difference in a Doppler shift between a satellite’s navigation signal and spoofing to identify the spoofing ,8. MonitData processing algorithms have also been studied as a means of detecting spoofing. When an antenna is rotating, the power measurements of the spoofing signals coming from the same direction change similarly and the correlation coefficients between them are close to 1, but the power measurements of the authentic signals are uncorrelated . A new aFinally, suppression algorithms using multiple antennas have been studied as a means of detecting spoofing interference. If a spoofing transmitter transmits spoofing signals from several different satellites at the same time, the spatial correlation of each spoofing signal can be detected by multi antenna direction finding (similar to an interferometer) ,21. SincAn adaptive spoofing interference suppression algorithm is proposed for satellite navigation based on a multi antenna array. This algorithm improves the real-time performance of spoofing suppression and reduces the complexity of spoofing interference suppression.A cross-correlation model of satellite navigation spoofing signals received by multiple elements is established. The feasibility of using the spread spectrum signals received between different array elements as a cross-correlation by which to suppress spoofing interference is analyzed.The complexity of the implementation of the adaptive spoofing suppressor for satellite navigation based on a multi antenna array is analyzed, and the performances of the two algorithms are verified by comparing them with the algorithm that first finds the direction of a signal and then suppresses it. The location performances of the two algorithms are tested under static and dynamic conditions.In the following sections, an adaptive spoofing-interference suppression algorithm is proposed for satellite navigation based on a multi antenna array. The cross-correlation gain of the spread spectrum signal received by the array is determined to be higher than the noise level, and the direction of the received signal does not need to be estimated, as this algorithm can realize the adaptive filtering of satellite navigation spoofing. It reduces the complexity of satellite navigation spoofing suppression and improves its performance. The main contributions of this paper are as follows:Assume an arbitrary atellite .If the received signal contains a spoofing signal, the received signal can be written asThe use of arrays to receive satellite navigation signals can enhance or suppress signals from different directions, thereby achieving suppression of satellite navigation interference signals.Filtering (despread) the received signal Let After despreading, the signal power becomes lgorithm ,28,29 caAssume that there is one desired signal and The corresponding signal subspace of the large eigenvalue expansion is Simultaneously, the array direction vector of the received signals is also orthogonal to the noise subspace. As such, the spatial spectrum function of the MUSIC algorithm Estimating the direction of arrival of the spoofing signal and the navigation signal is achieved via Equation (11).After determining the direction of arrival of the received signals, spoofing and navigation signals are identified based on their energy and direction angle. The array flow pattern subspace  can now According to the orthogonality of the signal subspace and the noise subspace, the noise subspace can be obtained:The optimization problem of beam weighting minimizes the power of residual interference and noise in the output. Since the optimal weight vector does not change the power of the target signal, the output signal-to-interference and noise ratio can be maximized. Using the Lagrangian multiplier algorithm, the solution of the optimal filter processor can be expressed asA block diagram of the implementation of the spoofing suppression algorithm based on DOA is shown in  Algorithms:The received signal of the array antenna is Despreading the signals received by multiple antennas for one satellite is expressed as The autocorrelation matrix The spatial spectrum function Subspace According to the optimal weight vector, the received signal of array antenna is filtered, and the filtered navigation signal is obtained, shown as The implementation process of this algorithm is complicated and not conducive to real-time implementation. The implementation process of the algorithm can be described as follows:Without estimating the direction of arrival of the spoofing signal, adaptive spoofing suppression is an effective way to reduce the complexity of the spoofing interference suppression.According to Equation (1), the cross-correlation of received signals from different array elements can be defined as:The low cross-correlation gain between different satellite signals is due to general pseudo-code characteristics, and the spoofing signal is less than the number of currently visible navigation satellites, Because real satellite signals come from different directions, it can be assumed that all spoofing signals come from the same source, such as Generally, the received power of the spoofing is about 5–10 dB higher than that of the satellite navigation signal. In other words, the spoofing gain is about 10–20 dB higher than the navigation signal after correlation despreading. The power of the satellite navigation signal to the receiving antenna is usually about 20 dB less than the noise. Taking the BeiDou B1 signal as an example, the gain of correlation despreading is about 21 dB. Different satellite navigation signals arrive from different directions, and array signal processing will restrict signal enhancement from a certain direction; therefore, the signals energy will not exceed the noise after cross-correlation between different channels. The cross-correlation gain of the spoofing signal is 10–20 dB higher than that of the navigation signal, which is to say that the level of the cross-correlation spoofing signal is above the noise. If the spoofing signal is a single-address broadcast spoofing signal, the array can receive multiple spoofing signals to achieve a superposition from the same direction.Therefore, formula (19) can be approximately equal to:By expanding the components of Equation (20), we can get:The cross-correlation gain generated by cross-correlation processing between the signals received by different antenna elements is shown in the The signals received by the array elements are completely submerged under the noise, and the adaptive notch algorithm cannot be used to achieve the suppression of spoofing. When the signals received by the two array elements are cross-correlated and coherently accumulated, a peak can be formed that is equivalent to that the energy of the received signal and higher than the noise. Therefore, the adaptive notch algorithm can be used to suppress spoofing.Assume the cross-correlation data length is After obtaining the covariance matrix after cross-correlation, the optimal weight of the adaptive notch can be calculated according to the following formula:Without directional constraints, The output of the adaptive filtering processing is Algorithms:The array antenna receiving signal is Any one of these can be selected as a cross-correlation reference signal using The cross-correlation vector of each signal and the reference signal are calculated for The cross-correlation matrix The constraint vector of the adaptive notch is generated according to constraint conditions The weight vector of adaptive notch is calculated by The array’s received signals are filtered by the calculated weights: There are three steps in the computation process of the spoofing suppression algorithm based on DOA. The first is despreading the received signal, assuming that the signal is despread in the form of Fast Fourier Transformation (FFT) transform . Without spoofing interference, the navigation signal had little effect on the performance of navigation and positioning after being processed by the two algorithms introduced in this paper. In order to more intuitively evaluate the impact of the two algorithms on positioning performance, mean square error was used. The mean square error of the positioning can be defined as:Without spoofing, the two spoofing suppression algorithms had little impact on navigation and positioning. The algorithm of the spoofing suppression algorithm based on DOA had almost no effect on navigation and positioning. The adaptive spoofing suppression algorithm had an impact on navigation and positioning in the X, Y, Z directions of ≤0.2 m.With spoofing, the general software receiver without spoofing suppression could not locate signals correctly; therefore, With spoofing, the positioning performance of the spoofing suppression algorithm based on DOA was slightly better than the adaptive spoofing suppression algorithm. The adaptive spoofing suppression algorithm was better than 2.5 m in the horizontal direction and better than 4.5 m in the elevation direction. In the static test, although the positioning performance of the adaptive spoofing suppression algorithm was slightly worse than the spoofing suppression algorithm based on DOA, the calculation and implementation complexity of the adaptive spoofing suppression algorithm were much lower.The kinematic positioning error had no obvious change compared with the static positioning error, which indicates that the adaptive spoofing suppression algorithm was not sensitive to the carrier motion state. The kinematic positioning mean square error is shown in The kinematic positioning error in the X, Y, Z axis direction was  for the spoofing suppression algorithm based on DOA, and  for the adaptive spoofing suppression algorithm. The positioning performance of the spoofing suppression algorithm based on DOA had no obvious advantage over the adaptive spoofing suppression algorithm. Compared with the static positioning performance, the positioning accuracy was almost unchanged in the horizontal direction, and the positioning accuracy was slightly worse in the elevation direction than in the static. This was caused by the fact that the dilution of precision (DOP) value of the navigation satellite in the elevation direction was worse than in the horizontal direction, and had nothing to do with the algorithm itself.The adaptive spoofing suppression algorithm for GNSS based on a multiple antenna array was been proposed that could utilize the cross-correlation gain of the multiple antenna array to adaptively generate nulling and achieve the simultaneous suppression of multiple spoofing signals. The performance of the proposed algorithm was verified through static and dynamic tests. The results show that: (1) ASSA has a better suppression performance on spoofing, and can form nulls in the direction of spoofing; (2) ASSA has a small impact on navigation and positioning, with positioning errors caused by ASSA less than 0.2 m; (3) after spoofing suppression, the static positioning error in the X, Y, Z axis was  for the ASSA, which is worse than the spoofing suppression algorithm based on DOA, but the calculation and implementation complexity of the ASSA were much lower; (4) after spoofing suppression, the kinematic positioning error in the X, Y, Z axis direction was  for the ASSA, with a performance similar to the spoofing suppression algorithm based on DOA. The algorithm proposed in this paper is not sensitive to the movement state of the carrier, and has good positioning performance under both stationary and moving conditions. In the future, this algorithm will be applied to navigation receiving terminals to improve their spoofing countermeasure performances.


Visible Light Communication (VLC) has received substantial research attention in the last decade. The vast majority of VLC focuses on the modulation of the transmitted light intensity. In this work, however, the intensity is kept constant while the polarization direction is deployed as a carrier of information. Demodulation is realized by using a differential receiver pair equipped with mutually orthogonal polarizers. An analytical expression to evaluate the Signal-to-Noise Ratio ( As the need for communication bandwidth increases persistently , VisibleRather than intensity based modulation in VLC, an additional interesting opportunity lies in modulating the polarization state of visible light. For instance, PIXEL  uses a pI in the transmission is given by  are used in order to transmit light with linear polarization. An ideal LP has a defined axis along which polarized light is unaltered. Light polarized orthogonally to this axis is either reflected or absorbed, depending on the type of polarizer. Unpolarized light passing through a LP is thus polarized along the axis of the LP. When linearly polarized light traverses a polarizer, the intensity given by , generalIn order to transmit data using linearly polarized light, the intensity of the transmitted light is kept constant, but the polarization axis is rotated orthogonally in order to represent ‘1’ and ‘0’ bits. To achieve this in practice, a setup using two identical LED transmitters h, as illustrated in Demodulation at the receiver can be effectively realized using a similar setup. A pair of photodiodes, A is identical for these complementary signals as illustrated in the upper part of In order to evaluate the impact of receiver rotation on the Taking the optical channel model and receiver polarizers into consideration, it can be shown that the received signals at the photodetectors are given by :(2)r1(t)Here e (AWGN) . These cTaking into account the differential signalling operation of A during a bit period As shown in the bottom part of quations  and applr is given by:Several definitions have been used to define the d of VLC . In thister (MF) , where tR with mean equal to:Each sample of the matched filter output corresponds to a sample of a Gaussian random variable The The relation between the As Equation , it can This ensures that at least one pair can receive the transmitted signal without severe attenuation due to receiver orientation. The maximum decrease due to receiver orientation is in this case reduced to As the noise was modeled as AWGN, the determined rding to ,22:(14)BQ-function is given byIn this equation, the The transmitter side consists of two power LEDs  driven at At the receiver side, two cases are considered. The first case, further mentioned as setup A, uses off-the-shelf available hardware to provide an initial evaluation. Two switchable gain Si detectors  are deployed, also equipped with mutually orthogonal polarizers. These polarizers are rotated in 5 degrees increments using a 3D-printed jig to mimic receiver rotation. Additionally, a custom receiver was designed for setup B. The receiver is based of a four quadrant (QD) photodiode  and is shown in In setup A and B, the LED transmitter switching voltages are controlled by a National Instruments USB-6215 Data Acquisition System (DAQ) and USB-6212, respectively in order to transmit data at 4 kbps. While the polarization differential modulation scheme allows for higher data rates, the data rate in this setup is mainly limited by the used hardware, namely the transient response of the power LEDs and corresponding drivers, and the DAQs used to sample the receivers. The data rate is thus deliberately chosen low as not to disfigure the measurement results and to assess the operating principle accurately. The same DAQ oversamples the photodetector voltages synchronously at 80 kHz. The differential signal is then calculated and DC-balanced to ensure the antipodality of the signal, taking into account any possible asymmetry between the LED transmitters and the receiver photodetectors. This results in a binary antipodal non-return-to-zero coded signal as described in r has its optimal decision threshold at the averaged expectation values of the matched filter outputs . Ho. Ho22]. The same procedure as for setup A is repeated with setup B to assess the Equation  drops toIn this work, a differential polarization modulation scheme using orthogonal polarizers at both the transmitter and receiver end of the VLC link is demonstrated. A general method to evaluate the


With the growth of the number of Internet of Things (IoT) devices, a wide range of wireless sensor networks (WSNs) will be deployed for various applications. In general, WSNs are constrained by limitations in spectrum and energy resources. In order to circumvent these technical challenges, we propose a novel cooperative phase-steering (CPS) technique with a simple on-off power control for generic spectrum sharing-based WSNs, which consists of a single secondary source (SS) node, multiple secondary relay (SR) nodes, a single secondary destination (SD) node, and multiple primary destination (PD) nodes. In the proposed technique, each SR node that succeeds in packet decoding from the SS and for which its interference power to the PD nodes is lower than a certain threshold is allowed to transmit the signal to the SD node. All SR nodes that are allowed to transmit signals to the SD node adjust the phase of their transmit signal such that the phase of received signals at the SD node from the SR nodes is aligned to a certain angle. Moreover, we mathematically analyze the outage probability of the proposed scheme. Our analytical and simulation results show that the proposed technique outperforms the conventional cooperative relaying schemes in terms of outage probability. Through extensive computer simulations, it is shown that the analytical results match well with the simulated outage probability as a lower bound. The Internet of Things (IoT) concept can be defined as all devices such as computing devices, mechanical and digital machines, objects, animals, or people in the world will be interconnected to collect and exchange data remotely for interaction with one another and with other devices and services over the Internet . Due to As part of an IoT topology, wireless sensor networks (WSNs) have been a key enabler of IoT, which can be described as a network of devices that can cooperatively sense the environment and may control the devices through a wireless link to communicate between persons, computers, or the surrounding environment . As the WSNs are composed of nodes that typically are equipped with batteries having a restricted power supply. The deployment of sensor nodes usually occurs in inaccessible environments, and with the limited battery capacity, their transmit power should be constrained for their lifetime. Therefore, wireless sensor nodes usually communicate with one another at short distances, and relay networks are used for larger transmission distances. Furthermore, if the physical channel is bad, the power constraint of nodes in WSNs is the main factor that degrades the system performance of WSNs .Therefore, data transmission with efficient energy consumption becomes an important design consideration for such networks. Meanwhile, cooperative communications with multiple relay nodes can collaborate to form virtual antenna arrays to achieve spatial diversity . If WSNsAmong various cooperative relaying techniques, a selective decode-and-forward (SDF) protocol, also known as opportunistic relay selection (ORS), has been considered one of the most practical strategies in the spectrum sharing-based cooperative network ,21. HoweTherefore, in this paper, as the main contributions, we modify the conventional CPS scheme for the spectrum sharing-based WSNs. Most importantly, only the secondary relay node that impacts the interference power less than certain interference constraints to the primary destination node can transmit the signal to the secondary destination node with the CPS scheme. By exploiting this method, we can strictly regulate interference to the primary destination node. Moreover, we mathematically analyze the outage probability of the proposed CPS technique in the spectrum sharing-based WSNs and demonstrate that the proposed CPS technique outperforms the conventional opportunistic relay selection scheme in terms of outage probability.The rest of this paper is organized as follows. In J primary destination (PD) nodes, and K secondary relay (SR) nodes. The wireless communication channels between the SS node and the We consider a spectrum sharing-based WSNs with multiple decode-and-forward (DF) relay nodes, as shown in We assume that the transmitters of primary networks are located far enough from the secondary network so that they cannot cause any interference to the SR nodes and SD node. Furthermore, it is assumed that the SS node and SD node are far from each other and that the fading between them is severe because of various obstacles in the WSN. The SS node does not directly affect the SD node. Therefore, the SS node can communicate with the SD node only through SR nodes. In addition, we assume that each In this section, we describe the overall procedure of the proposed CPS technique. In the first hop, the SS node sends the signal to all SR nodes, and the received signals at the R indicates the required data rate when the SS node and the SD node directly communicate with each other. In order to perform phase alignment in the second hop, all relay nodes must know the original signal without noise. Therefore, each Q. The interference channel information between each SR node and PD nodes can be obtained at the SR node through the periodic sounding of pilot signals transmitted by PD nodes. Each SR node decides if its interference power from itself to the PD nodes is lower than the distributed interference constraint Q for each PD node can be automatically satisfied when each SR node satisfies its distributed interference constraint since the actual number of SR nodes that transmit the signal to the SD node is less than K. Then, the index set of the SR nodes that satisfy the interference power constraint at the second hop is defined as:K. Hence, we can define the available set of SR nodes that belong to both At the second hop, we define the interference power constraint, also known as the interference temperature, at each PD node as fined in , since ai out of K SR nodes are available to transmit the signal as:In this section, we mathematically analyze the outage probability of the proposed CPS technique for the spectrum sharing-based WSNs. First, we should obtain the probability that each SR node successfully decodes and satisfies the interference power constraint in order to calculate the probability that the SR node belongs to the available set A. From , the sucNow, we show the outage probability of the SD node, i.In , withouti RVs and can be represented by the sum of i independent RVs following the Rayleigh distribution. The probability density function (PDF) and the CDF of Since The exact PDF of RV h itself , and we As mentioned earlier, the PDF of Since each z2 as in . TherefoK as follows:R is the required data rate of the entire system, it can be regarded as the transmit rate at which the SS node intended to transmit. Therefore, the effective throughput in  ,21 schemK, when K increased due to the increase of the spatial diversity gain. It is worth noting that the performance improvement of the proposed CPS technique became significant as the number of SR nodes increased.Q, when the transmit Q values. Furthermore, the performance improvement of the proposed CPS became significant as the number of SR nodes increased, as well, as described in The outage probability performance of the proposed scheme according to In In this paper, the cooperative phase steering (CPS) technique with on-off power control was proposed for generic spectrum sharing-based wireless sensor networks (WSNs), which consisted of a single secondary source node, a single secondary destination node, multiple secondary relay nodes, and multiple primary destination nodes. In the proposed CPS technique, secondary relay nodes that succeeded in decoding the signal from the secondary source node and the transmit power of which was lower than a certain interference threshold were allowed to send the received signal at the second hop so that its interference to the primary destination nodes was maintained lower than an interference constraint. We mathematically analyzed the outage probability of the proposed CPS technique and validated that the proposed CPS technique outperformed the conventional opportunistic relay selection scheme in terms of outage probability and throughput, especially when the number of secondary relay nodes was large.


Porcine respiratory coronavirus (PRCoV) infects the epithelial cells in the respiratory tract of pigs, causing a mild respiratory disease. We applied air–liquid interface (ALI) cultures of well-differentiated porcine airway cells to mimic the respiratory tract epithelium in vitro and use it for analyzing the infection by PRCoV. As reported for most coronaviruses, virus entry and virus release occurred mainly via the apical membrane domain. A novel finding was that PRCoV preferentially targets non-ciliated and among them the non-mucus-producing cells. Aminopeptidase N (APN), the cellular receptor for PRCoV was also more abundantly expressed on this type of cell suggesting that APN is a determinant of the cell tropism. Interestingly, differentiation-dependent differences were found both in the expression of pAPN and the susceptibility to PRCoV infection. Cells in an early differentiation stage express higher levels of pAPN and are more susceptible to infection by PRCoV than are well-differentiated cells. A difference in the susceptibility to infection was also detected when tracheal and bronchial cells were compared. The increased susceptibility to infection of bronchial epithelial cells was, however, not due to an increased abundance of APN on the cell surface. Our data reveal a complex pattern of infection in porcine differentiated airway epithelial cells that could not be elucidated with immortalized cell lines. The results are expected to have relevance also for the analysis of other respiratory viruses. Alphacoronavirus in the family Coronaviridae  antibody . The nuclei were stained by 1 μg/ml DAPI , and embedded with ProLong® Gold Mountant . Immunofluorescence analysis was performed using a Nikon Eclipse Ti microscope and NIS Elements AR software , or using a TCS SP5 confocal laser scanning microscope equipped with a 63 ×  oil HCX PL Apo objective . ImageJ/Fuji software calculated the expression amount of pAPN.To analyze the cell tropism of PRCoV, IFA was performed as previously described . BrieflyTo determine the infectivity of the harvested supernatants, a focus-forming assay was performed as described previously with some modifications . BrieflyIf not stated otherwise, experiments were performed at least six times with samples derived from three donors. Results are expressed as the means with standard error of the mean (SEM). Data were analyzed by one-way ANOVA with Tukey’s post-hoc test, using GraphPad Prism  software.To characterize the infection of porcine airway epithelial cells by PRCoV, we determined the site of virus entry and virus release in well-differentiated porcine tracheal epithelial cells (wdPTECs). Cells that had been differentiated on filters were infected from either the apical or basolateral side. At daily intervals post-infection, the media from the apical and basolateral compartments were analyzed for the presence of infectious PRCoV. As shown in To elucidate the cell tropism of PRCoV, we infected wdPTECs with PRCoV. At one-day post-infection, the cells were fixed with 3% PFA and stained for the presence of virus antigen, cilia (β-tubulin) and/or mucins (mucin-5AC). The result of the co-localization anaylsis by confocal immunofluorescence microscopy is shown in For many viruses, the expression and distribution of appropriate receptors on the surface of host cells are a major determinant of the cell tropism. Therefore, we attempted to elucidate the location of pAPN on the respiratory tract. We applied immunohistochemistry (IHC) to stain pAPN on the porcine trachea and on wdPTECs . IHC staThe expression of the receptor might depend on the state of cellular differentiation . To valiNext, we analyzed whether the change in the expression of pAPN during differentiation affects the infection by PRCoV. We infected early differentiated PTECs (edPTECs) and well-differentiated PTEC (wdPTECs), respectively, with PRCoV. As shown in PRCoV replicates predominantly in the lungs and is mostly detected in the lower respiratory tract . First, Understanding the host–pathogen interactions at the cellular and molecular level is important for attempts to control disease. We developed an ALI culture system for differentiated porcine airway epithelial cells, and inoculated PRCoV on this in vitro model. Subsequently, we used IFA or IHC staining to visualize the receptor and viral antigen. To our knowledge, this is the first time that animal coronavirus infection and its receptor distribution have been investigated in differentiated airway epithelia cells. We showed for the first time that well-differentiated cells support PRCoV replication with viral entry and egress occurring primarily from the apical surface. We report that pAPN is more abundantly expressed on the apical than on the basolateral surface of tracheal cells and PTECs, and the distribution of pAPN is correlated with the PRCoV tropism. One point of special interest was the novel observation that PRCoV infection of porcine airway epithelia was dependent upon the state of epithelial differentiation. A difference in the susceptibility to infection was also detected when tracheal and bronchial cells were compared. The increased susceptibility to infection of bronchial epithelial cells was, however, not due to an increased abundance of APN on the cell surface. Since APN is also the receptor for several other human and animal viruses, these findings are relevant also for understanding the infection by these more common pathogens.One of the most striking findings of this study is related to the cell tropism of PRCoV. Identification of the cell types infected by PRCoV is a crucial piece of information about the pathogenesis. The results reveal that PRCoV preferentially targets non-ciliated and non-mucus-producing cells. The human coronaviruses, HCoV-229E and MERS-CoV, have also been reported to preferentially infect non-ciliated cells ,24. HoweThe tissue distribution of APN is one of the determinants in the pathogenesis of coronavirus infections. Various in vitro models were established to investigate the expression of the receptor ,26,27,28The type and number of different cells in the respiratory tract varies at different stages of differentiation. In the very early phase, basal cells are predominant. At a later stage, the basal cells have started to differentiate into ciliated cells and goblet cells. When this process is finished, the airway epithelium consists of well-differentiated cells ,31. In oThe receptor is important for viral entry, but it is certainly not the only determinant . In a stIn summary, we elucidated the pathogenesis of PRCoV on the porcine airway epithelial cells to analyze the route of infection and viral tropism. These findings are expected to also apply to coronaviruses of other species. In addition, we provided the new insights that expression of APN is dynamic and associated with cellular differentiation, a finding that may underlie susceptibility to infection. Taken together, these porcine airway epithelial cells will help us to address questions concerning emerging respiratory coronaviruses and may even provide the platform to study potentially efficacious therapeutic options.


This paper first portrays the equilibrium payoff of enterprise’s cooperation of environmental governance based on the Cournot model. Secondly, the evolutionary game model in complex networks is adopted to depict the evolution of environmental governance cooperative behavior among enterprises. Further, the evolutionary process of environmental governance cooperative behavior of enterprises is simulated considering the supervision behavior of government and the reputation evaluation behavior of environmental social organization. The results show that the cooperation level of enterprise group under self-organization condition will reach a low level; the supervision of government can enhance the cooperation level of enterprise group with high betrayal tempatation while it has limited effect on enterprise group with low betrayal tempatation. The reputation evaluation behavior of environmental social organization can realize reputation effect to improve the the cooperation level of enterprise group with high betrayal tempatation. The enhance of reputation sensitivity can optimize equilibrium distribution of reputation and it can strengthen the reputation effect on cooperation level. Based on the analysis above, the suggestions to effectively improve cooperation level are given. As the main producer of environmental pollution, enterprises bear the important responsibility for environmental pollution governance. However, the diffusivity of environmental pollution leads to a significant positive externality of the environmental governance behavior of enterprises. As a result, some enterprises have the motivation to be eduction . Therefoeduction . If entemultiple co-governance pattern in China, the evolutionary driving force of corporate environmental governance cooperation is not only the endogenous driving force generated by the self-organization of enterprise group, but also the exogenous driving force generated by other subjects, such as government and environmental social organizations [The formation and evolution of environmental governance cooperative behavior among enterprises can be depicted as a dynamic evolutionary games process in which the agents of enterprise group finally reach an equilibrium state through mutual learning . The evoizations ,6. The eTherefore, this paper, from the perspective of multiple co-governance, introduce the reputation effect, applying the evolutionary game model in complex network to study the formation and evolution of enterprise group environmental governance cooperative behavior, so as to explore the evolutionary rules of environmental governance cooperative behavior among enterprises.Viewed from existing literature, the researches on corporate environmental governance cooperative behavior are mainly carried out from the perspective of corporate production decision-making, because the environmental governance cooperation will directly affect corporate production cost and change the market structure, ultimately making an impact on corporate earnings. In current research, oligopoly competition model is an important tool to study the production cooperation decision-making among enterprises and how it lead to the change of market structure, and Cournot game model is the typical one to be focused by many scholars ,8,9. TheIn the research on corporate environmental governance cooperation, the market relationships among enterprises is also an important factor which affects the corporate cooperative behavior. Relevant studies show that the relationships among enterprises in a group is essentially a complex network, whose topological structure can be characterized by complexity such as small-world and scale-free . TherefoThe first one to establish the research on evolutionary games in complex networks would be Nowak and May , and relIn current multiple co-governance pattern, the evolutionary driving force of environmental governance cooperation among enterprises is not only including internal driving force formed by the interaction among agents of enterprise group, but also including the external driving force of government and environmental social organizations ,24,25. FTherefore, this paper will construct the model by introducing reputation effect and apply system simulation to explore the evolutionary process of cooperation among enterprises. The rest of the paper is structured as follows. The assumptions and the analytical framework of this paper are provided in In order to analyze the cooperative behavior among enterprises in environmental governance, several assumptions are provided as follow.Assumption 1.ij shared by node i and node j denotes the product market where the products are provided by enterprise i and enterprise j.We assume that the enterprise group consist of N enterprises, and there exists social network construction among the enterprises which is resulted at their social relationship. According to recent literature, the enterprise network can be depicted by small-word networks for its small-world characteristics. In this network, the node denotes the firm and, the edge eAssumption 2.The production of the firm will make pollution emission and it needs to carry on environmental governance. Suppose that the enterprises play two-player games between each two enterprises in network, and the strategy set of enterprise is {Comletely governance (C), Uncomletely governance (U)}. In the two-player game, if the players both select strategy C, we can say that the cooperative behavior is realized in this game. Therefore, we use the proportion of enterprises who selected strategy C to measure cooperation level of enterprises group during environmental governance.Assumption 3.Assumed that two enterprises belong to the same edge denotes that the two enterprises occupy this market and play Cournot game. The equilibrium of the game will determine the equilibrium price of the market, the equilibrium output of specific two enterprises and their equilibrium payoffs.Assumption 4.Government supervises the environmental governance behavior of enterprises. Meanwhile, environmental social organizations evaluate the reputation of enterprises and have an impact on the evolution of corporate reputation.The relationships among enterprises always presents multiplicity, which means that an enterprise not only belongs to a single market, but also in multiple markets, and this forms the complex interaction among enterprises. If the enterprises are regarded as nodes and the market relationships are regarded as edges, the enterprise group can be depicted as a complex network with interlacing and multithreading structure.In this paper, the reasons to use a complex network to depict the enterprise group structure can be explained from the following two aspects: (1) the analysis of the game among enterprises needs to rely on the network structure, because the network structure will have an impact on the final equilibrium, so it is closer to the reality taking the network structure of enterprise groups into consideration; (2) the evolution process of the game among enterprises involves strategy transformation, and their learning behavior is not only concerned with economic benefits, but also affected by reputation effect, while the spreading of reputation effect also needs the structure of group relationship as the action space. Therefore, it is more reasonable to explore the cooperation among enterprises in the analytical framework of complex networks.Under the complex network context, the analytical framework can be constructed as i and enterprise j can be constructed as follow in Based on the assumptions above, the payoff matrix of the two-player game between enterprise i and enterprise j are depended by Cournot game model.And it is assumed that the payoff of enterprise i is j is Suppose that the output of enterprise The production decisions of enterprises can be also influenced by environmental preference of consumers , so the i for instance, under different strategy selections as follows:When i and enterprise j: (1) enterprise i selects strategy C while enterprise j selects strategy U; (2) enterprise i and enterprise j both select strategy C; (3) enterprise i and enterprise j both select strategy U. In these three situations, we can obtain the equilibrium payoffs of enterprise i and enterprise j through solving the Cournot model between enterprise i and enterprise j, which contains the several steps: (1) constructing the payoff fuctions of enterprise i and enterprise j according to their strategy selections; (2) calculating their optimal reaction functions of the two enterprises by solving the first order condition; (3) obtaining the equilibrium output according to final equilibrium condition, and calculating the equilibrium payoff furtherly. After these steps, the equilibrium payoffs of the two enterprises in these three situations can be obtained as follows , which means that proportion of enterprises which are effectively supervised by government is r in every evolutionary step. The government levies environmental tax on enterprises in the process of environmental supervision and the environmental tax rate is supposed to be (1) if the enterprise supervised has selected strategy C, the environmental tax should be calculated according to the direct pollution emission (2) if the enterprise supervised has selected strategy U, the environmental tax should be calculated according to the sum of direct pollution emission i will adopt the strategy of enterprise j is:K denotes the noise in strategy updating. And the tradional Fermi rule, like formular (28), only considers the economic payoff, while it ignores the reputation effect. In reality, the reputation effect is of importance in mutual learning among enterprises. This paper will introduce the reputation effect into mutual learning by the following two aspects:After the games among enterprises and the supervision of government, enterprises have obtained payoff in this evolutionary step. Then the enterprises will make strategy updating by mutual learning. Accoring to relavent research, we can realize the strategy updating through Fermi rule, the probability that enterprise i is i adopts the strategy of enterprise j not only considering economic payoff, but also reputation. Then the payoff of players which takes reputation effect into consideration can be revised to be i will adopt the strategy of enterprise j is also revised to be:(1) Define the reputation variable of enterprise (2) Setting the updating rule of reputation The change of reputation Based on the algorithm designed above, the whole evolutionary period is set to be TT, and the simulation of evolution process of cooperation among enterprises is conducted circularly on the basis of the steps above until the end of specified evolution period.N = 1000, the average degree of the small-world networks Ks = 6, the rewiring probability to generate networks pr = 0.02. In the Cournot game between enterprises, a = 12, c = 2, ϕ = 1.5, and Rmax = 100; In the Fermi function for strategy updating of enterprises, the noise K = 0.1. Based on the parameter setting above, we can realize the simulation of the evolutionary process of environmental governance cooperative behavior through Matlab. During the simulating process, the evolutionary period TT = 1000, which denotes that a complete evolutionary process contains 1000 steps. The final simulating results are the average results obtained by 5 repeated simulation experiments, aiming to reduce the interference from system error.Without loss of generality, we set the quantity of enterprise group In the condition that government’s regulatory behavior and environmental social organization’s reputation evaluation behavior are absent, while there may exist environmental preference, we first conduct the simulation for the evolution of enterprises’ cooperative behavior, and the results are shown in According to However, from the current situation of industrial development in China, the price gap between environment-protecting product and ordinary product is relatively small, for which the reasons can be summarized from two aspects. On one hand, the relatively slow industrial development in China leads to low environment-protecting added value of product, resulting that it is not conducive to the realization of price leverage of environmental protection product. On the other hand, the environment-protecting products in China are mainly positioned as middle-end or high-end products and the market proportion is small so that pollution-intensive products are still dominated by high-pollution industries, leading to the difficulty to promote the formation of environmental cooperative behavior among enterprises through marketing adjustment.For the fact that it is hard to realize environmental cooperative governance by marketing adjustment, the government’s supervision will be an approach to achieve the goal. Suppose that there doesn’t exist environmental preference  mainly appears in energy-intensive industries, and under marketization condition, enterprises in energy-intensive industries tend to improve their output at the cost of environmental pollution because they will pay high opportunity cost if they participate in effective environmental governance cooperation. In this situation, through the leverage effect of environmental tax in supervision, the government can effectively internalize the pollution damage cost caused by these enterprises into their economic benefits, thus forcing these energy-intensive enterprises to participate in environmental governance cooperation and the cooperation level of can be improved effectively. However, enterprise groups with small betrayal temptation (0 < b < 0.7) always exist in high-tech industries with high environment-protecting level. However, enterprise groups with small betrayal temptation (0 < b < 0.7) always exist in high-tech industries with high environment-protecting level. Aiming at these enterprises, the government’s supervision behavior may not be able to achieve its expected effect, because that if the government’s supervision intensity fails to reach a certain degree, which means that the enterprise’s environmental tax imposed is not beyond its expected threshold-value range, making them bear the corresponding environmental tax rather than participate in cooperative behavior, or become temporizer in cooperation decision-making, further strenthing the speculation attitude of some enterprises to select strategy U, and making it hard to promote the cooperation level of enterprise group, resulting in governmental invalidity in environmental governance.u of environmental social organizations.The government’s supervision behavior has limitations on the improvement of the cooperation level of enterprise groups with low-level betrayal temptation. In order to improve the cooperation level of enterprise group with low-level betrayal temptation, reputation effect is introduced into evolutionary analysis. And at the same time, the reputation evaluation behavior of environmental social organizations is also introduced, who play the role that it conducts third-party supervision on enterprise groups and evaluate their corporate reputation. In the case of considering the reputation effect, we study how the cooperative behavior is affected by the reputation evaluation intensity Firstly, we set that corporate reputation sensitivity According to In addition to the environmental social organization’s reputation evaluation intensity u, the corporate reputation sensitivity It can be seen from It is worth noting that when ocess as , demonstFrom analysis of the influence of corporate reputation sensitivity on evolution of enterprise group cooperation, in addition to government’s supervision behavior and reputation evaluation behavior of environmental social organization, it is also an important way to promote the level of corporate environmental governance cooperation to improve the environment-protecting awareness of enterprises and their attention to intangible assets such as environmental governance reputation.In this paper, the Cournot model is applied to construct payoff matrix of the game between enterprises, and then we adopt the evolutionary game in complex networks to construct the evolutionary game model of enterprise environmental governance cooperative behavior, and carries out the simulation analysis on its evolution process. With the detail analysis above, we can get some major conclusions as follows: (1) Under the self-organization evolution of enterprise group environmental governance, the cooperation level of environmental governance will eventually reach a low level;(2) The government’s environmental supervision behavior can effectively improve the cooperation level of enterprise group under high betrayal temptation, but supervision failure will appear in the enterprise group with low betrayal temptation;(3) The reputation evaluation behavior of environmental social organizations can make up for the limitation of government supervision through reputation effect and effectively improve the cooperation level of enterprise group with low betrayal temptation;(4) The low corporate reputation sensitivity is not conducive to the realization of the reputation effect through environmental social organization on the evolution of enterprise cooperative behavior and the enhancement of the reputation sensitivity of enterprises can optimize the equilibrium distribution of reputation and promote the cooperation level of enterprise group.Based on the empirical analysis and major conclusions above, this paper puts forward some implications:(1) For enterprises, they should be aware of that collective action dilemma of enterprise group in pollution controlling will not be conducive to the sustainable development of enterprise in the long run. To get out of this dilemma, the enterprise should not only pay attention to the present economic benefits, but also pay attention to the environmental governance reputation, improving the environment-protecting consciousness in the production and creating green reputation, in order to realize the exemplary role in the enterprise group.(2) For the government, it is necessary to strengthen the supervision on enterprises’ environmental behavior and expand the scope of environmental supervision. In the process of supervision, grid management pattern in environmental supervision should be implemented, and the power and responsibility of relevant environmental supervision departments should be clearly allocated, so as to build a completed environmental supervision mechanism and achieve a situation in which environmental governance performance is effectively maintained.(3) For environmental social organization, they should not only actively participate in third-party supervision, effectively restraining the environmental behavior of enterprises through the force of public opinion, but also positively carry out the environment-protecting education, improving enterprises’ emphasis on environmental governance behavior and environmental reputation. In this way anti-driving effect of reputation on cooperation of enterprise group can be effectively used to promote the sustainable development and realize win-win cooperation in environmental governance.


Aberrant origin of the subclavian artery (SCA) is a well-known vascular anomaly as part of congenital heart diseases with the left subclavian artery (LSCA) being more frequently affected than the right subclavian artery (RSCA). Complete isolation of the SCA is an even more infrequent aortic arch anomaly, occurring in less than 1% for the LSCA and even less for the RSCA. Isolation of the RSCA in patients with d-transposition of the great arteries (D-TGA) is even scanter with only a hand full of cases being reported in the literature. However, isolation of the RSCA has important implications on hemodynamics and surgical strategies. In this case report, we present a newborn patient with D-TGA which presented with distinct differential cyanosis. While the right upper extremity appeared pink with an oxygen saturation of 100%, the rest of the body was cyanotic. At first, this appearance was interpreted as the Harlequin phenomenon during primary care. However, detailed echocardiography revealed an aberrant origin of the RSCA from the right pulmonary artery, which led to the differential cyanosis. The patient underwent arterial switch operation on day of life two including dissection and reimplantation of the RSCA. The special hemodynamic situation of this is discussed in terms of pathophysiology and as well as its impact on perioperative and surgical management. We present the case of a newborn with d-transposition of the great arteries (D-TGA), where remarkable differential cyanosis initially assumed as the Harlequin phenomenon led to the diagnosis of an isolated right subclavian artery (RSCA). We discuss hemodynamics, embryology, and implications on preoperative and surgical planning.2 measured 100% at the right arm, while the rest of the body appeared cyanotic with SaO2 levels of 75% . Fetal echocardiography had suggested D-TGA with a small perimembranous ventricular septum defect (VSD) and possible coarctation of the aorta. The atrial septum defect (ASD) was described as unrestrictive, and no further associated cardiac lesions or vascular abnormalities had been reported. He was delivered by Cesarean section at gestational week 38 and showed sufficient postnatal adaption with an Apgar score of 9, 9, and 9. Throughout primary care, the patient presented with marked differential cyanosis, leaving the right arm and right quadrant of the chest pink with SaOs of 75% . InitialThere was no difference in the peripheral pulses with good palpability in all four extremities. Noninvasive blood pressure recordings showed similar systolic blood pressure with values around 80 mmHg, while diastolic blood pressure in the right arm was slightly decreased (35 mmHg) compared to the other extremities (41–44 mmHg).Transthoracic echocardiography revealed a parallel course of the great arteries. The artery originating from the left ventricle bifurcated into the right and left pulmonary arteries, whereas the artery originating from the right ventricle was determined as the aorta with a left-sided aortic arch. These findings were consistent with D-TGA with anterior-posterior alignment of the great arteries. A small ASD with a size of 4 mm as well as a ductus arteriosus (DA) with predominantly left-to-right shunting, but some right-to-left shunt during systole, was displayed. Detailed echocardiographic evaluation revealed a left-sided aortic arch with three head/neck vessels. Both coarctation of the aorta as well as a perimembranous VSD, which had been described by fetal echocardiography, could be ruled out during the examination. Notably, neither a branching of the first vessel nor an origin of RSCA distal to the left subclavian artery (LSCA) in terms of a lusoria artery could be visualized. However, an anomalous artery could be displayed in multiple views originating from the right pulmonary artery (RPA) with course between the superior vena cava and aorta towards the right arm . The finPgE1-infusion  was started shortly after delivery with 15 ng/kg/min. The initial distinct cyanotic appearance, together with a peripheral saturation of 75% and the existence of a small ASD, led to the consideration of a balloon atrial septostomy (BAS). However, as the left-to-right shunt through the ASD could clearly be demonstrated to be unrestricted allowing adequate mixing, as blood gas analysis did not show metabolic acidosis, and as cerebral oxygen saturation remained stable, BAS was not performed, eventually. These findings were consistent with an increase of the peripheral saturation up to 83% with advancing postnatal cardiorespiratory adaption.On day 2, the child underwent arterial switch operation. Intraoperatively, the surgeon could visualize the RSCA originating from the RPA at the level of the distal main right branch. Ligation and dissection of the RSCA was performed with subsequent reimplantation to the ascending aorta.Postoperatively, blood pressure differences have not been observed and neither paleness nor temperature differences were noted. One year after surgery, the patient is presenting in excellent clinical condition with appropriate growth of the formerly affected extremity and without any differences in peripheral pulses or blood pressure.Written informed consent was obtained from the patient's parents for publication of the case report and the newborn's image.Aberrant origin of the subclavian artery (SCA) is well known to be part of CHD, especially when the aortic arch demonstrates hypoplasia or obstruction. Diagnosis is made mostly by echocardiography prior to surgery and eventually confirmed by CT- or MRI scans. Anomalous origin and course are more common for the LSCA than for the RSCA. While in the majority of anomalies of the SCA blood supply is provided from the aorta, origin of either the RSCA or LSCA from the pulmonary artery (PA) is extremely rare.In the presented case, unusual differential cyanosis led to the diagnosis of an isolated RSCA in a newborn with D-TGA. The combination of a D-TGA with an isolated RSCA has only been reported in a few cases , 2. Howeth intersegmental artery with the right 4th aortic arch. The right 6th aortic arch normally forms the RPA and the right DA, from which the latter usually involutes. In the presented case involution of the right 4th aortic arch resulted in migration and connection of the right 7th intersegmental artery to the right 6th aortic arch, which further led to an aberrant origin of the RSCA from the RPA via a right persisting DA.Isolation of the RSCA can be explained on the basis of Edwards' hypothetical double arch . Within Hemodynamic consequences of this rare finding differ widely, depending on the filling characteristics. While in otherwise normal biventricular circulation with normal pulmonary and systemic resistance, blood flow is directed towards the PA and will induce the clinical findings of diminished pulses and lower blood pressure at the right arm. In the scenario where the DA remains open, the RSCA presents as a systemic-to-pulmonary shunt accepting blood from the vertebrobasilar system and donating to the PA , leading to pulmonary overcirculation with risk of congestive heart failure.As in our patient, a neonate with D-TGA, pulmonary pressure and resistance are high and direction of blood flow could be demonstrated as reversed flow from the RPA to the RSCA. Keeping in mind that the PA in D-TGA is connected to the left ventricle with fully oxygenated blood, saturations were measured 100% and pressure differences to the systemic circulation did not occur. Both carotid arteries as well as the LSCA fill from the aorta, which supplies the systemic circulation with deoxygenated blood and thereby gives cyanotic coloring of the skin perfused by these vessels.Initially, the distinctly delimited differential cyanosis led to the assumption of the Harlequin phenomenon, which is a sudden change in skin color in newborns due to sympathetic autonomic dysregulation of the peripheral vascular tonus . HoweverDifferential cyanosis, as described in our patient, can more frequently be encountered in a totally different hemodynamic situation, namely, in newborns with pulmonary hypertension (PH) and persistent ductus arteriosus (PDA), interrupted aortic arch, or coarctation of the aorta. These situations have, in common, that desaturated blood flows into the descending aorta via a right-to-left shunt over the PDA, which may cause cyanosis of the lower body half. In case of a postductal origin of the LSCA, this can lead to a similar differential cyanosis as in the presented case. However, since the diagnosis of D-TGA had already been described prenatally in this patient, PH with a PDA could be ruled out in this case, as this would have led to a reverse differential cyanosis. Reverse differential cyanosis can occur in infants with D-TGA with PH or coarctation of the aorta, which causes increased right-to-left ductal shunting of saturated blood and thereby higher postductal peripheral saturation. PH in patients with D-TGA is a critical hemodynamic condition, as increased vascular resistance leads to a predominant right-to-left shunt across the DA, which causes a decrease in pulmonary blood flow and, therefore, an increase of the cyanosis . In caseThe amount of differential cyanosis between the different skin areas depends on mixing of blood at the atrial and ductal level. Our patient had only a small ASD, which allowed systemic saturations of 75% to 83%. This could be clearly distinguished from the fully oxygenated RSCA, supplying the right arm and right chest wall.The accurate diagnosis has several implications in the medical care of these patients.It is very important that invasive blood pressure monitoring on the neonatal intensive care unit and during heart surgery should not be performed on the right arm, as these pressures reflect the hemodynamics in the pulmonary rather than the systemic circulation. Furthermore, measurement of invasive blood pressure on the right arm would lead to discontinuous monitoring during ligation and reimplantation of the RSCA.2-monitoring, cerebral oxygenation is the most critical parameter and would, in the setting of D-TGA with RSCA, be reflected most accurately by recording the left arm tracing. It is also this saturation that gives most information on whether a balloon atrioseptostomy should be performed for better mixing between the circulations.For transcutaneous SaOThe surgical decision to reconnect the RSCA to the aortic arch, as done in our case, may be preventive for subclavian steal syndrome on the long run, as described in one case with D-TGA and isolated RSCA  or more Clinical appearance of differential cyanosis presenting as the Harlequin phenomenon should be taken seriously in neonates with cyanotic CHD and not brushed aside. Meticulous echocardiographic evaluation and eventually additional CT or MRI investigation provides the diagnosis of anomalies of the head neck vessels that may influence hemodynamics, perioperative preparation, and surgical strategy significantly. Pathophysiology of aberrant or isolated RSCA affords cardiovascular thinking also in nonspecialized neonatology units.


This paper presents a model for assessing the performance of self-propelled rotary tool during the processing of hardened steel. A finite element (FE) model has been proposed in this analysis to study the hard turning of AISI 51200 hardened steel using a self-propelled rotary cutting tool. The model is developed by utilizing the explicit coupled temperature displacement analysis in the presence of realistic boundary conditions. This model does not take into account any assumptions regarding the heat partitioning and the tool-workpiece contact area. The model can predict the cutting forces, chip flow, induced stresses, and the generated temperature on the cutting tool and the workpiece. The nodal temperatures and heat flux data from the chip formation analysis are used to achieve steady-state temperatures on the cutting tool in the heat transfer analysis. The model outcomes are compared with reported experimental data and a good agreement has been found. The innovations in material science contribute to the emergence of new materials. These modern materials exhibit peculiar mechanical and thermal properties. Such materials, due to their remarkable properties have numerous applications in high-performance industries such as the biomedical sector, sensors, aerospace, automobile, etc. Nevertheless, on the one hand, the excellent properties of these materials are advantageous, on the contrary, they pose obstacles and difficulties in the machining of these materials. The serious challenge that arises when such materials are being machined is intense heat emission which in turn influences the wear and machining efficiency of the tool ,2,3.Several methods have been practiced to address the problem of elevated heat generation, such as using liquid coolant in the machining zone ,5,6. TheThe rotary cutting tool can be described as a tool that portrays the shape of a circular disk and that rotates around its center. Compared to the traditional turning tool in which a single cutting point is utilized, the rotary tool rotates around its center during machining and the cutting process takes place throughout the cutting edge perimeter  owing to this rotation. There are primarily two kinds of rotary tools that have been described in the literature, namely Actively Driven Rotary Tool (ADRT) and Self-Propelled Rotary Tool (SPRT) . The toow/Al composite by employing carbide rotary cutting methods, particularly SPRT. Their findings showed that the tool life of rotary tools was considerably greater than that of the traditional tools. Similarly, the consequences of SPRT were investigated during the machining of aerospace material  [Various researches can be listed out in the literature that have carried out experimental studies to examine the performance of SPRT in machining difficult to cut materials. For example, Chen et al.  publishe8 alloy) . The ana8 alloy)  conducte8 alloy)  also intEl-Mounayri et al.  administThere are several factors, namely cutting speed, depth of cut, feed rate, tool wear, tool geometry, etc., that can affect the quality of SPRT machining. Consequently, numerous studies examining the different variables can also be highlighted in the literature. For example, Armarego and Katta  establisHao et al.  describeAlthough, multiple experimental studies and mathematical models related to the use of SPRT, its variables, advantages, and disadvantages have been discussed in earlier works. However, there is a very limited number of studies in the literature that have utilized Finite Element (FE) for SPRT analysis. For example, a research work modeled the distribution of the tool temperature in SPRT when hardened steel was machined . The FE The apparent disinclination to implement FE can be attributed to the difficulties in SPRT modeling and complexities inherent in its machining process. Certainly, it is imperative to introduce FE models that can figure out machining conditions depending on the different machine settings due to the significant expense of actual machining with rotary tools. The evolution of an accurate and precise FE model is essential to understand the machining mechanism of the rotary tools and to further improve their efficiency for difficult to machine materials. In this study, a three-dimensional (3D) FE model has been accomplished to simulate the formation of chips, while using coated carbide SPRT for AISI 51200 hardened steel machining. A coupled temperature displacement analysis is conducted using ABAQUS/Explicit. This model can predict different performance measures, such as cutting forces, chip morphology, stresses, and temperature in the workpiece and the cutting tool. Since the coupled temperature displacement analysis is computationally costly, this model cannot be used to predict steady-state temperatures on the cutting tool. Therefore, the heat transfer analysis is carried out using ABAQUS/STANDARD to model the steady-state temperatures on the cutting tool and the heat flux. The boundary conditions are incorporated using the outputs from the chip formation analysis. Finally, the model developed is validated concerning cutting forces using the outcomes reported in Dessoly et al. .The continuum elements with a temperature degree of freedom are preferred for the tool and workpiece. A total of 14112 elements are created using selected mesh schemes on the tool and workpiece. The identical cutting tool geometry as well as the process variables  model is chosen which is frequently found in applications of high strain rate deformation such as the metal cutting. The flow stress of J-C can be defined using Equation (1):D’ is estimated for each element which compares the total equivalent plastic strain in the element with the failure strain. The fracture is initiated when D is equivalent to 1. Factor ‘D’ can be obtained using Equation (2):The J-C damage model has been exploited to model the separation of chips from the workpiece. The damage criterion factor ‘1D to 5D symbolizes J-C damage parameters for the workpiece material and are calculated experimentally by using tensile and torsion tests. σ* is the proportion of pressure stress to the von-mises stress. The J-C plastic model and damage parameters are listed in In the second phase, the heat transfer analysis is undertaken using ABAQUS/STANDARD and the user subroutine DFLUX to simulate the moving heat source for extracting the steady-state temperatures on the cutting tool. The general heat conduction formulation can be denoted by Equation (4):Considering the moving source rotational speed as The equation of continuity and the final energy balance equation can be represented by Equations (7) and (8).The simulation values of the cutting and thrust forces indicate adequate consistency with the experiments and the average error is about 7%. This error can be attributed to various issues associated with model creation. For example, uncertainties related to material flow and damage model parameters in addition to constraints with the chip separation criterion depending on the element deletion method.The simulations have also been performed for the fixed tool instance to examine the impact of tool rotation on chip formation and temperature generation. Chip formation and von-mises stress contours based on the rotary and fixed tools at the cutting speed of 100 m/min are displayed in The temperature contours for the fixed and rotating tool cases at the cutting speeds of 100 m/min are illustrated in sλ) on cutting quality. The chip formation at different inclination angles can be viewed in The simulations are also undertaken at the inclination angles of 9°, 25°, and 33°, in addition to the standard inclination angle of 17° to explore the implications of the tool inclination angle (The DFLUX subroutine in ABAQUS/STANDARD can be used to retrieve the steady-state tool temperature as mentioned earlier. The 3D FE model established for hard turning using SPRT predicts cutting forces with an acceptable degree of precision.The tool-chip contact length for the rotary tool case is observed to be lower due to the variations in the chip flow angles.Temperatures are higher for the fixed tool case in the chip forming analysis owing to a slow heat conduction compared to the rotating tool.Tool surface temperatures for rotating tools are estimated to be approximately 35% lower than the fixed tools.The tool inclination angle has a major effect on various output variables such as chip formation, cutting forces, and temperatures.Cutting forces are reported to vary in a fluctuating manner for the range of inclination angles explored. The minimum cutting force is observed at the inclination angle of 25° corresponding to the lowest contact length of the tool-chip.Tool surface temperatures decrease initially and then increase with the angle of inclination. The lowest tool temperature is also located at a 25° angle of inclination.The 3D FE model has been established to examine the hard turning of AISI 51200 hardened steel by utilizing a self-propelled cutting tool. The model is built by incorporating the explicit coupled temperature displacement analysis in the existence of plausible boundary conditions. The model is implemented to estimate the cutting forces, chip flow, stresses, and the temperature distribution on the cutting tool and the part. Since the coupled temperature displacement analysis is computationally expensive, this model cannot be utilized to project the steady-state temperatures on the cutting tool. Therefore, the heat transfer analysis is accomplished using ABAQUS/STANDARD to simulate the steady-state temperatures on the cutting tool and the heat flux. The cutting forces of the model are correlated with experimental data, and a good agreement has been identified. The following inferences can be drawn out from the investigation:Finally, it can be concluded that the comparison of steady-state temperature profiles for the rotating and fixed tool cases demonstrates the strengths of the rotating tool. The rotating tool case has a low and uniform temperature distribution, which improves the tool performance and surface integrity of the workpiece.