Safe Boundary Research Articles

Unlocking the Safety Issues Caused By Internal Short Circuits in Lithium-Ion Batteries

Lithium-ion batteries (LIBs) have been attracting tremendous focuses and fundamental impetus for the fast development of electric vehicles, computers, cellphones and among others . Mechanical loading may catastrophically cause battery internal short-circuit (ISC) and then usually lead to irreversible and chain reaction until the dead of the cell. Possible hazards such as excessive heat, gas/smoke, fire and explosion of LIBs triggered by ISC greatly refrains further wide application of LIBs as well as developing higher energy density LIBs. However, a clear picture of the LIB’s electrochemical safety behavior triggered by mechanical loading is still uncovered. Here we systematically show that there are three modes of electrochemical behavior for LIBs after ISC, i.e. fast voltage drainage with no thermal runaway (TR), several cycles of voltage drop-recovery followed by TR, and a significant voltage-drop followed by TR, triggered by mechanical abusive loading. By highly repeatable tests, detailed characterization and computation modeling, we found that electrochemical safety behavior of LIBs is dominated by SOC, ISC area and resistance. Our results demonstrate the safe boundary and electrochemical behavior map for LIBs after ISC. We anticipate that this discovery will lead to new opportunities for LIB safety design, manufacturing, assembling, evaluation and protection.

Multimodal image fusion technology for diagnosis and treatment of the skull base-infratemporal tumors

To explore the value of incorporated multimodal image fusion technology with computer-aided design of the skull base-infratemporal tumor treatment. A retrospective study was carried out to enroll seventeen patients with skull base-infratemporal tumors treated at Peking University Hospital of Stomatology from February 2011 to September 2018. Plain CT, enhanced CT and MRI data were imported into the iPlan 3.0 software (BrainLab navigation system), and the image fusion was performed for each patient preoperatively. Then the three-dimensional images of the tumor, vital vessels and craniofacial bones were reconstructed to prepare virtual operation design. We evaluated the application of multimodal image fusion technology that had been incorporated with computer-aided planning during the navigation-guided biopsy or surgery, through the analysis of the biopsy and operation data and regular follow-up postoperatively. The mean age of 17 patients (7 males and 10 females) was 46 years. Primary tumors occurred in 11 cases, and recurrent tumors in 6 cases. The size of the 17 tumors ranged from 2.9 cm to 9 cm, and the mean size was 4.35 cm. There were 7 cases with skull base bone destruction and/or intracranial extension, and 10 cases with tumors adjacent to the skull base. High-quality multimodal fused images were obtained in all the 17 cases. The spatial-position relationships of the tumors, adjacent craniomaxillofacial bones and vital vessels labeled with different colors were displayed well on the generated fusion images. The multimodal image fusion technology that incorporated with computer-aided three-dimensional reconstruction and then applied in navigation-guided biopsy or surgery showed that, preoperative analysis and virtual operation design functioned with good results, especially in cases with small tumor size, recurrence or illdefined borders in the skull base-infratemporal region. Operation was carried out in 16 cases after preoperative diagnosis and assessment, and 1 case was performed by navigation-guided biopsy only. The proportions of navigation-guided surgery and biopsy were 70.6% (12/17) and 17.6% (3/17) individually. The positive rate of pathologic diagnosis using navigation-guided biopsy was 100% (3/3). All the navigation-guided biopsies or operations were carried out successfully. Complications included 1 case of cerebrospinal fluid leak from a recurred meningioma patient postoperatively, and 1 case of facial paralysis resulting from parotid-gland deep lobe tumor. Most (14/15) tumors got complete removal with safe boundary through intra-operative navigation verification and post-operative imaging confirmation, except for one case of subtotal resection to avoid the injury of cavernous sinus. The pathological results of the tumors could be classified to mesenchymal (10), adenogenous (3), neurogenic (3) or epithelial (1) resources. The follow-up time ranged from 3 to 94 months, with the median follow-up time of 9 months. Taking full advantages of individualized multimodal images, could help analyze the three-dimensional spatial position relationship of tumors, vital vessels and craniofacial bones properly, and then complete the virtual operation design well. The incorporated multimodal image fusion technology with navigation technology may improve the accuracy and safety of core needle biopsy and surgical treatment of skull base-infratemporal tumors.

Dynamic Sliding-Mode Control Scheme for Hypersonic Vehicles Considering Nonminimum Phase Characteristics and Performance Recovery

This paper presents a performance recoverable control scheme for air-breathing hypersonic vehicles (HSVs) with nonminimum phase characteristics. As elevator and throttle are the only two control inputs available for longitudinal trajectory tracking of HSVs, there are two representative problems emerged. One is the nonminimum phase behavior in pitch dynamics of HSVs due to elevator-to-lift coupling, which prevents the application of standard inversion-based control techniques. The other is the engine performance recovery control with the disabled propulsion system, when flight states of HSVs exceed the safe working boundary, causing engine flameout. In view of the above, a comprehensive control scheme is proposed to realize performance recoverable and high-precision trajectory tracking of nonminimum phase HSVs. First, a dynamic integral sliding-mode (DISM) control method based on the Byrnes-Isidori (B-I) normalized form is proposed, achieving asymptotic tracking of velocity and flight path angle (FPA) while stabilizing internal dynamics. The control method transforms the FPA tracking problem into a stabilization problem of an augmented system consisting of internal dynamics and dynamic compensator, making closed-loop pole adjustable, and thus improves the tracking performance. Second, on this basis, a performance recoverable control scheme is proposed to achieve the automatic performance recovery of HSVs when the engine flameout occurs due to the stall of the HSVs. It achieves temporary acceleration by adjusting the trajectory, thus obtaining the conditions for engine restart. The simulations of the nominal condition and engine flameout condition are presented, respectively, to verify the proposed control scheme. From the simulation results, the proposed control scheme is shown to have superior tracking accuracy with internal dynamics stable, and the robustness is fully verified by the Monte Carlo simulations. Especially, speed autonomous recovery and engine restart are achieved during the engine flameout, which demonstrates the effectiveness of the proposed performance recovery control scheme.

FLAC3D Simulation Analysis of the Extended Height of the Water-induced Fracture Zone in Different Coal Seams

Most and local minable seam in mining field has seven layers, according to the label from top to bottom in turn as follows:13, 12, 10, 9, 8-3, 8 -2, 8-1. coal, total minable seam thickness of 21.92 m, dip angle of coal seam located between 4° and 24°, is nearly horizontal seam. The average thickness is 116.48m. Given the existence of tertiary pore fissure aquifer, in order to predict effectively the impact of the aquifer on site production when seven layers of coal are mined, this paper uses FLAC3D numerical simulation for comparative analysis of the coal mining water fractured zone height, which determine the safe mining boundary thereby provide theoretical guidance for the field working face layout, mining area connection and other safety production.

Investigation and Emulation of Junction Temperature for High-Power IGBT Modules Considering Grid Codes

Grid-connected converters in wind turbine systems play a more active role in the future power grid dispatching for fulfilling specified grid codes. Hence, the diversified demands and faults from grid sides bring more intense thermal fatigue to the power modules. This paper proposes an investigation method for junction temperature (T j ) variation considering grid code constraints in laboratory environment. For the most cases of 690-V wind power systems, an MW-level H-bridge test setup with energy circulation is established. In the case of particular grid code requirements and T j control strategy, the equivalent voltage and current stresses can be reproduced and applied to the inspected insulated gate bipolar transistor (IGBT) power modules. To investigate the real-time T j under specific work conditions derived by grid codes, turn-off delay time-based thermal electrical sensitive parameter method is used for T j estimation. Consequently, a test procedure for the safe operation boundary of power converter using T j limitation as a new criterion is proposed. Finally, three types of typical operation conditions for a 1.5-MVA power converter are chosen for the validation of the proposed method. The typical conditions under grid code requirements can be reproduced and the corresponding real-time T j variation can be extracted. With the T j acknowledge, the safe operation boundary and parameter optimizations of IGBT modules can be determined by real T j instead of case temperature.

The Associated Absorption Features in Quasar Spectra of the Sloan Digital Sky Survey. I. Mg ii Absorption Doublets

Abstract Using the SDSS spectra of quasars included in the DR7Q or DR12Q catalogs, we search for Mg ii λλ2796, 2803 narrow absorption doublets in the spectra data around Mg ii λ2798 emission lines. We obtain 17,316 Mg ii doublets, within the redshift range of 0.3299 ≤ z abs ≤ 2.5663. We find that a velocity offset of υ r < 6000 km s−1 is a safe boundary to constrain the vast majority of associated Mg ii systems, although we find some doublets at υ r > 6000 km s−1. If associated Mg ii absorbers are defined by υ r < 6000 km s−1, ∼33.3% of the absorbers are supposed to be contaminants of intervening systems. Removing the 33.3% contaminants, ∼4.5% of the quasars present at least one associated Mg ii system with . The fraction of associated Mg ii systems with high-velocity outflows correlates with the average luminosities of their central quasars, indicating a relationship between outflows and the quasar feedback power. The υ r distribution of the outflow Mg ii absorbers is peaked at 1023 km s−1, which is smaller than the corresponding value of the outflow C iv absorbers. The redshift number density evolution of absorbers (dn/dz) limited by υ r > −3000 km s−1 differs from that of absorbers constrained by υ r > 2000 km s−1. Absorbers limited by υ r > 2000 km s−1 and higher values exhibit profiles similar to dn/dz. In addition, the dn/dz is smaller when absorbers are constrained with larger υ r . The distributions of equivalent widths, and the ratio of , are the same for associated and intervening systems, and independent of quasar luminosity.

ISOLINE OF THE BORDER OF NAVIGATION SAFETY ZONE OF A VESSEL

[For the English abstract and full text of the article please see the attached PDF-File (English version follows Russian version)].ABSTRACT Prevention of the majority of emergency situations in navigation is based on observing a certain distance between vessels, which allows timely taking precautionary measures in order to avoid contact. The thus created conditional space of safety distances forms a navigation safety zone. The article gives a universal conceptual definition of such a zone, a generalized structural classification of factors affecting its size and shape, the nature of the isolinear zonal boundary. The concepts of isoasphalia as an idealized safe boundary, as well as an isoasphalic surface forming an idealized safe area around the vessel are introduced. On the basis of set theory, a variational law of variation of piecewise functions describing a safe space asymmetric with respect to the vessel’s diametric plane is derived. The resulting expression allows us to identify the boundary of an asymmetric elliptical navigation safety zone. Keywords: sea vessels, navigation safety, idealized model, isoline boundary, isoashpalia, isoasphalic surface, asymmetric elliptic zone, set theory, variational law.

Intelligent Navigation of Mobile Robot Using Grey Wolf Colony Optimization

Path optimization is a vital aspect in the design of Mobile Robot, which saves precious time and energy. In this paper, Autonomous Mobile Robot (AMR) is imitated the Grey Wolf searching possessions and navigated to reach the target, beneath collision free, in various environments with different shaped obstacles. Grey wolves succeed in hunting through packs. These wolves glue together forever and follow the leader of the pack with communicating among them through howl. GWO algorithm has a capability to flee from local optima and facilitates to reach towards global maxima. The simulation and experiment results are compared against Probabilistic Road Map method, and proved that Navigation of AMR with GWO algorithms is robust to overcome sharp edged obstacles. The Integration of Safe Boundary Algorithm with GWO algorithm yielded better results.

Power optimization of a single propeller airplane take-off run on the basis of lateral maneuver limitations

The problem of selecting optimal take-off run power of a single propeller airplane on the basis of the lateral maneuver limitations is analyzed in this paper. The single propeller reactive torque as the function of engine power and speed generates non-aerodynamic asymmetric load disturbance. The capability of lateral flight control surfaces to compensate for this asymmetric load and perform the required maneuver defines the safe flight envelope boundaries in the form of engine power setting – airspeed relation. The take-off run length consisting of acceleration, decision making, brake activation and airplane stopping length distances is calculated for engine power settings along the safe flight boundaries defined by the lateral flight control capabilities. The minimum of take-off run along thus defined safe flight boundary determines the engine optimal power setting. The results are presented for the example of the single propeller airplane on concrete runway surface.

A Comparative Analysis of Endoscopic-Assisted Transoral and Transnasal Approaches to Parapharyngeal Space: A Cadaveric Study.

Background Surgical resection of parapharyngeal space (PPS) tumors is very challenging. An endoscopic-assisted surgical approach to this region requires detailed and precise anatomic knowledge. The main purpose of this study is to describe and compare the detailed anatomy of the PPS via transnasal transpterygoid (TP) and endoscopic-assisted transoral (TO) approaches. Materials and Methods Six fresh injected cadaver heads (12 sides) were prepared for dissection of the PPS via TP and TO approaches. Computed tomography (CT) with image-based navigation (Navigation System II; Stryker, Kalamazoo, Michigan, United States) was used to identify bony structures around the PPS. Results TP and TO approaches could both expose the detailed anatomical structures in the PPS. The TP approach can provide a direct route to the upper PPS, but it is limited inferiorly by the hard palate and laterally by the medial and lateral pterygoid muscles. However, the TO approach can provide a direct route to the lower PPS, but it is difficult to expose the area around the Eustachian tube. The styloglossus and stylopharyngeus muscles could be considered as the safe anterior boundary of the parapharyngeal internal carotid artery (ICA) with the TO approach. Dissection between the stylopharyngeus muscle and the superior pharyngeal constrictor muscle provides direct access to the parapharyngeal ICA. Conclusion The TP and TO approaches provide new strategies to manage lesions in the PPS. The important neurovascular structures of the PPS could be identified with these approaches. The endoscopic-assisted TO approach can provide direct access to the parapharyngeal ICA.

Dramatherapy for Facilitating an Older Adult's Psychological Transition into a Nursing Home: A Case Study

This article presents a case study that explores the potential of drama therapy to facilitate an older adult’s psychological transition into a nursing home. It describes how drama therapeutic techniques helped him externalise his feeling of meaninglessness and playfully articulate it within the safe boundary of drama therapeutic space. The challenges to establishing a therapeutic relationship along with transference and counter-transference issues are examined. In tune with the client’s needs, the mode of therapy adopted was individual therapy based on an integrated drama therapy model. Both qualitative and quantitative methods were used for assessment. Dramatherapy was found to be effective in dealing with the client’s feeling of meaninglessness, general distress, social withdrawal, and lethargy. It also helped him improve his social relations, engage in recreational activities, and find meaning in life in a nursing home. The framework of therapy, assessment, procedures, process, techniques, outcome evaluation and limitations of the study are discussed in detail.

Implantation of the anterior atlantoaxial lateral mass intervertebral cage using the transoral approach.

The purpose of this study was to evaluate the possibility of implanting the anterior atlantoaxial lateral mass intervertebral cage, a new type of fixation, by the transoral approach. This study examined the possibility of implantation invivo by the quantitative measurement on the dry atlantoaxial bone and implantation of the anterior atlantoaxial lateral mass intervertebral cage in specimens. Anterior atlantoaxial lateral mass intervertebral cages were implanted in 10 atlantoaxial joint specimens using the transoral approach. Eight anatomical parameters (width, the thickness, ordinates, abscissas, and declination angles of the mass) from each of the 30 dry atlas and axis bone specimens were measured. These parameters determined the size and the design of the cage and the way of implantation. The course of the vertebral artery forms the safe boundary for transoral surgery. The shape of the area of work exposure was an inverted trapezoid. In specimens, the anterior atlantoaxial lateral mass intervertebral cages could be successfully implanted using the transoral approach. The parameters of the human atlantoaxial lateral masses exposed anteriorly showed that there was enough space, for the safe anterior implantation of the cage. The surgery using the transoral atlantoaxial reduction and plate makes possible the implantation of the anterior cage. The implantation of anterior atlantoaxial lateral mass intervertebral cage through transoral approach is possible.

Navigation of non-holonomic mobile robot using neuro-fuzzy logic with integrated safe boundary algorithm

In the present work, autonomous mobile robot (AMR) system is intended with basic behaviour, one is obstacle avoidance and the other is target seeking in various environments. The AMR is navigated using fuzzy logic, neural network and adaptive neuro-fuzzy inference system (ANFIS) controller with safe boundary algorithm. In this method of target seeking behaviour, the obstacle avoidance at every instant improves the performance of robot in navigation approach. The inputs to the controller are the signals from various sensors fixed at front face, left and right face of the AMR. The output signal from controller regulates the angular velocity of both front power wheels of the AMR. The shortest path is identified using fuzzy, neural network and ANFIS techniques with integrated safe boundary algorithm and the predicted results are validated with experimentation. The experimental result has proven that ANFIS with safe boundary algorithm yields better performance in navigation, in particular with curved/irregular obstacles.

Numerical modelling of suffusion by discrete element method: a new internal stability criterion based on mechanical behaviour of eroded soil

Non-cohesive soils subjected to a flow may have a behavior in which fine particles migrate through the interstices of the solid skeleton formed by the large particles. This phenomenon is termed internal instability, internal erosion or suffusion, and can occur both in natural soil deposits and also in geotechnical structures such as dams, dikes or barrages. Internal instability of a granular material is its inability to prevent the loss of its fine particles under flow effect. It is geometrically possible if the fine particles can migrate through the pores of the coarse soil matrix and results in a change in its mechanical properties. In this work, we uses the three-dimensional Particle Flow Code (PFC3D/DEM) to study the stability/instability of granular materials and their mechanical behavior. Kenney and Lau criterion sets a safe boundary for engineering design. However, it tends to identify stable soils as unstable ones. The effects of instability and erosion, simulated by clipping fine particles from the grading distribution, on the mechanical behaviour of glass ball samples were analysed. The mechanical properties of eroded samples, in which erosion is simulated and gives a new approach for internal stability. A proposal for a new internal stability criterion is established, it is deduced from the analysis of relations between the mechanical behaviour and internal stability, including material contractance.

Świętosława – Skandynawistka

Abstract The article deals with Świętosława (also known as Sigrid the Haughty, Sigrid Storråd, Gunhilda), a figure from the early days of Polish statehood and Christianity, member of the Piast dynasty, a queen of Sweden, Denmark and Norway, a mother of the Canute the Great, a (Viking) king of England and finally both Slav and Pole, and British, and Nordic can be approached from various perspectives. The particularly appealing appears however the opportunity to reflect on the Nordic dimension in Polish social thought, culture and politics. Świętosława faced a challenge of learning the Nordic people, their language, and all this that is included in the programme of Scandinavian studies at the University of Gdansk “from inside”. Her situation resembles the one investigated by Jerzy Szacki in his sociological survey of tradition. It refers to learning oneself an others once the safe boundary is overstepped and the first step towards what is foreign, different and perhaps shocking is made. It relates to the authentic adventure of migration, but also to education and cross-culture communication promoting mutual understanding of differences and to new perspectives for community development. Finally, it concerns the geopolitical implications of northern dimension for the Polish political ethos, culture and education

A multiple metrics approach to prioritizing strategies for measuring and managing reactive nitrogen in the San Joaquin Valley of California

Human alteration of the nitrogen cycle exceeds the safe planetary boundary for the use of reactive nitrogen (Nr). We complement global analysis by analyzing regional mass flows and the relative consequences of multiple chemical forms of Nr as they ‘cascade’ through multiple environmental media. The goals of this paper are (1) to identify the amounts of Nr that flow through a specific nitrogen rich region, (2) develop multiple metrics to characterize and compare multiple forms of Nr and the different damages that they cause, and (3) to use these metrics to assess the most societally acceptable and cost effective means for addressing the many dimensions of Nr damage. This paper uses a multiple metrics approach that in addition to mass flows considers economic damage, health and mitigation costs and qualitative damages to evaluate options for mitigating Nr flows in California’s San Joaquin Valley (SJV). Most analysis focuses attention on agricultural Nr because it is the largest flow in terms of mass. In contrast, the multiple metrics approach identifies mobile source Nr emissions as creating the most economic and health damage in the SJV. Emissions of Nr from mobile sources are smaller than those from crop agriculture and dairy in the SJV, but the benefits of abatement are greater because of reduced health impacts from air pollution, and abatement costs are lower. Our findings illustrate the benefit of a comprehensive multiple metrics approach to Nr management.

Output Constraint Control on Path Following of Four-Wheel Independently Actuated Autonomous Ground Vehicles

The path-following problem for four-wheel independently actuated autonomous ground vehicles is investigated in this paper. A novel output constraint controller is proposed to deal with the lateral offset control in path following and maintain the vehicle lateral stability in the presence of tire sliding effects. The innovations of this work lie in the following two aspects: 1) A novel output constraint control strategy, namely, the hyperbolic projection method, is proposed to strictly bound the lateral offset to prevent the vehicle from transgressing the safety bound in path following; 2) an adaptive and robust linear quadratic regulator controller is adopted to obtain the optimal active front-wheel steering and direct yaw-moment control inputs with vehicle lateral stability consideration and to eliminate the effect of parameter uncertainties. CarSim–Simulink joint simulation results indicate that the proposed controller can compactly bound the lateral offset to avoid transgressing the safe boundary during path following, particularly in extreme driving conditions, in the presence of tire sliding effects and system uncertainties.

Prestellar cores: initial orbit and boundary

The initial orbit of a prestellar core in the resisting intercore medium is found to be an elliptic spiral round the mass centre of the parent molecular cloud (clump), with exponentially decreasing semiaxes, high constant eccentricity, and constant period. Prestellar cores are stable against perturbations caused by the parent cloud, if the corresponding mean density contrast is larger than about 10. This value defines the safe boundary of a prestellar core within its parent cloud and is in accordance with observations.

Micromechanical characterisation of weld metal susceptibility to hydrogen-assisted cold cracking using instrumented indentation

Hydrogen-assisted cold cracking is generally accepted to be the consequence of a critical concentration of hydrogen trapped within a susceptible microstructure and subjected to a threshold level of stress. Traditionally, hardness has been used as a proxy for establishing the critical limits above which the risk of a hydrogen crack propagating is considered significant. However, developments in the steel-making process, in particular thermomechanically controlled processing, has brought into question the suitability of empirical hardness limits developed using older generation steels. In this paper, a safe welding boundary was established for single-pass root runs for API 5 L X70 steel welded with E6010 electrodes. Across this boundary, it was shown that hydrogen cracks were present in welds with hardness’s well below the traditionally accepted threshold of 350 HV. This paper explores the use of nanoindentation as means of quantifying the susceptibility of welds deposited on high-strength low-alloy steels, using shielded metal arc welding, to hydrogen-assisted cold cracking. It is suggested that the use of the hardness/elastic modulus (H/E) ratio, which is directly related to the yield strength of a material, is a more suitable parameter to predict weld metal hydrogen-assisted cold cracking (HACC) susceptibility than is the hardness alone.

A 176-Channel 0.5cm3 0.7g Wireless Implant for Motor Function Recovery after Spinal Cord Injury.

Epidural spinal stimulation has shown effectiveness in recovering the motor function of spinal cord transected rats by modulating neural networks in lumbosacral spinal segments [1, 2]. The state-of-the-art neuromodulation implant [3] reports a 4-channel stimulator with wireless data and power links for small animal experiments, yet weighs 6g and has a volume of 3cm3. It is preferable that the implant package has a comparable size to its bioelectronics and a high-density stimulator to support stimulation with high spatial resolution. Furthermore, the epidural electrode should be soft and flexible because a mechanical mismatch exists at the tissue-electrode interface [1]. Unlike other implant/SoCs that stimulate with pre-loaded patterns [4–5], the implant for motor function recovery should be capable of adaptively adjusting its stimulation patterns at run time in response to the subject's varying physiological states [2]. Measuring the electrode-tissue impedance is also critical to ensure safe stimulation. Deriving the equivalent circuit model of the electrode-tissue interface determines the safe stimulation boundary (i.e. pulse width and intensity) to ensure the electrode overpotential is within the water window [6]. However, an SoC implementation of this function has not been reported.