In the state of the art of steel production, the temperature evolution of steel strips is typically controlled to regulate the phase contents indirectly and, with this, their material properties. ...This paper proposes a novel computationally efficient, real-time capable dynamic model that captures both the temperature evolution and the phase transformations in the steel strip. The steel strip is processed in a cooling section after a continuous annealing furnace. The phase transformations cover the austenite decomposition which is mainly controlled by specifically decreasing the temperature during the cooling process. For this, a phenomenological state-space model is derived, which is inspired by the Johnson-Mehl-Avrami-Kolmogorov and the Koistinen-Marburger model. Phase transformations generally change the specific latent heat of the material, which is captured in the proposed distributed-parameter model of the strip temperature by an energy balance. Lumped-parameter models are used for the temperature evolution of the wall, the rolls, and the radiant tubes. Heat transfer due to convection, radiation, and conduction couple the individual thermal submodels. A comparison of simulation results and measurements from both experimental material tests and the real plant operation demonstrate the accuracy and feasibility of the proposed model. The model is computationally inexpensive and serves as a solid basis for advanced real-time control and optimization.
•A mathematical model is proposed to describe the evolution of temperature and phases in a steel strip during cooling.•The austenite decomposition is captured by a phenomenological phase transformation model.•The model is computationally efficient and real-time capable.•The accuracy and the suitability of the proposed model is demonstrated by comparing simulation results with measurements.
Conventional lateral flow test strip (LFTS) sensors are insufficiently accurate and reliable due to their single-target detection with limited sample information in a single test. The increasing ...demand for the simultaneous determination of multiple analytes has recently been accelerating the rapid development of high-throughput and multiplexed LFTS sensing technologies. In this contribution, we systematically summarize the recent achievements on the design, development, and application of multiplexed LFTS sensors for improved rapid on-site diagnostics. The discussion focuses on emerging design strategies to increase multiplexing capacity for enhancing analytical efficiency and precision. As a proof-of-concept, several typical examples are presented. The advantages and disadvantages of such approaches are critically analyzed. Finally, we briefly discuss the current challenges and future perspectives.
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•Emerging design strategies to develop multiplex lateral flow test strip sensors were systematically summarized.•The underlying principles of each design strategy were highlighted.•Several seminal examples for each strategy implemented for multiplexing were discussed.•The potential challenges and further perspectives in this field were elaborated.
The coiling of a steel strip in a Downcoiler is an integrated part of the hot-rolled steel production line. Failure to coiling results damage to finished rolled strip along with mill downtime due to ...cobble. Thus, coiling success in Downcoiler is a critical concern for production of hot rolled steel strip. A mathematical model has been developed to analyze coiling feasibility for new grade of high strength steel to be rolled for the first time in the mill and to thereby identify a safe operating window for the coiling-process parameters. This has significant benefit in reducing the risk of coiling failure during plant trial and thus product development cycle time. The model is based on the estimation of coiler tension for a new grade with reference to mill-based physical data of coiling compactness as defined by a wrapper angle from known grades, coiled in the mill. This is followed by computation and comparison of coiling torque vis-à-vis the capacity of the Downcoiler allows a decision to be taken about the coiling feasibility of the new grade. It is believed that it is for the first time that a coiling feasibility algorithm has been developed and discussed. The model has been widely used within Tata Steel to carry out plant trails for the development of new grade as well as rolling of new section in existing grades at its Hot Strip Mill in Indian plant at Kalinganagar.
The wide-width titanium strip cold rolling, as an efficient titanium material processing technology, has been widely concerned. During the cold rolling process, high-order flatness defects occur ...frequently, seriously restricting the improvement of titanium product quality. To analyze the mechanical deformation behavior of titanium strips during cold rolling, and explore the influence of entrance and exit profile index on the generation of high-order flatness defects. An integrated coupling rolling model of the roll system and the strip has been established based on the FEM method, and the accuracy of the model has been verified using on-site measured data. The research results show that when the taper or coning amount of the first intermediate roll increases, if the entrance profile index remains unchanged, the exit profile index will significantly decrease, and the high-order deflection deformation of the work roll axis will occur, ultimately leading to high-order flatness defects. When using the first intermediate taper roll to control the exit profile index, if the exit profile index remains unchanged, the entrance profile index increases by 10 μm, and the coning amount will increase by 8.3mm. Therefore, a plan based on the optimization of the entrance profile index has been proposed, which takes into account both the profile and the high-order flatness, to achieve a smaller coning amount to meet the exit profile index and decrease the risk of high-order flatness. The industrial test results show that after the implementation of the plan, the occurrence rate of high-order flatness decreased by an average of 34.42%.
Jad traces the transformation of the Palestinian women’s movement from the 1930s to the post-Oslo period and through the Second Intifada to examine the often-fraught relationship between women and ...nationalism in Palestine. Offering one of the first intensive studies of Islamist women’s activism, Jad also explores the impact of emerging feminist NGOs in depoliticizing the secular Palestinian women’s movement. Studying these two developments together illuminates the nature of women’s engagement in the Palestinian space, challenging myths of gender roles’ "immutability" under Islamand the supposed "modernizing" benefits of Western-style activism.
•A dual electrochemical channel-based biosensor has been developed.•The dual channel Sensor can simultaneously measure the glucose and ketone with only one blood drop.•The dual channel sensor has the ...acceptable accuracy as compared to the clinical biochemical analyzer.•It paved the way for clinical point of care identification of diabetic ketoacidosis.
The traditional design of enzymatic test strip has single electrochemicalreaction, which can only measure one single biochemical parameter. We present one disposable electrochemical test strip with dual enzymatic reaction channel which is capable of simultaneously measuring glucose and blood ketone by one fingertip whole blood drop for clinical identification of diabetic ketosis (DK) and diabetic ketoacidosis (DKA). The blood glucose was measured in the 1st channel while blood ketone was measured in the 2th channel. The proposed test strip fulfils the rigid demand for diabetic patients with DK/DKA without double pricking the finger to determine the blood glucose and blood ketone, respectively. The results of clinical identification of diabetic ketoacidosis by the proposed test strip was verified by the clinical test with good consistency. The proposed test strip provides a cost effective and fast solution for clinical point of care identification of diabetic ketoacidosis.
The strip shape inheritance model is widely applied to improve the strip shape quality in tandem cold rolling (TCR). However, the inheritance mechanism is still currently unclear. To bridge this gap, ...this paper presents a new numerical method for calculating the strip crown inheritance factor. In addition, the effects of the entry strip crown on exit strip crown and flatness were quantitatively analysed at each stand in the TCR using a novel three-dimensional (3D) multi-stand elastic–plastic finite element (FE) model. The results show that the strip crown inheritance factor increases slowly from S1 (stand 1) to S3 (stand 3), while rising sharply from S3 to S5 (stand 5), reaching a peak value of 0.495 μm/μm at S5. This trend coincides with that of strip plastic rigidity, which verifies that the strip crown inheritance factor is dependent on the strip plastic rigidity. Furthermore, the variation of strip crown and flatness under different entry strip crowns from S1 to S5 is jointly influenced by the pass reduction and strip plastic rigidity. Moreover, the strip crown inheritance factor increases with the deformation resistance of the strip at both S1 and S5. These findings not only offer a fresh perspective to understand the mechanism of strip crown inheritance, but also provide an important basis for optimising the strip shape control in the TCR process.
Feeding a cold steel strip into continuous casting (CC) mold is an effective method to improve the quality of large round bloom. However, it is difficult to assess the correlation between the bloom ...quality and the initial temperature of the strip. Therefore, a three‐phase mixed columnar–equiaxed solidification model is developed to evaluate the effect of feeding strip temperature on macrosegregation and solidification structure in a large vertical CC round bloom. The results show that feeding the steel strip induces “crystal rain” in the liquid core of the bloom and increases the volume fraction of the equiaxed phase. After feeding a strip, the flow direction of molten steel is changed, and the flow velocity is increased in the liquid core of the bloom. Furthermore, with initial temperature of the strip decreases, the production efficiency is improved. Compared to the four conditions investigated, the carbon distribution in the bloom is the most uniform, the negative segregation at the centerline of the bloom is the weakest with the value of −35.50%, and the extreme value difference of the macrosegregation index at 20 m below the meniscus is the smallest with the value of 38.35% under the condition of
T
initial
= 500 K.
To comprehensively understand the effect of oscillation on cooling capacity of steel strip, a mathematical model is proposed to investigate the distribution of temperature fields in continuous cast ...slabs, taking into account the oscillatory feeding process. Strip oscillation results in a periodic variation of nearby molten steel flow. It intensifies the turbulence of surrounding molten steel and enhances the interfacial heat transfer. During the feeding process, the morphology of strip undergoes three stages: upheaval, fluctuation, and disappearance. As the strip oscillation frequency increases, the maximum cross‐sectional area of the strip gradually decreases during the upheaval stage, the fluctuation stage gradually disappears, and the strip disappearance speed gradually increases during the disappearance stage. These observations suggest that an increase in the oscillation frequency accelerates the melting of the strip, which is caused by the enhanced heat transfer between the strip and molten steel. This results in a gradual growth of strip's cooling capacity and a decrement in the liquid fraction of molten steel surrounding the strip. In addition, feeding strip is advantageous in preventing the jet from impinging onto narrow surfaces of slab. The blocking effect initially increases and then remains almost unchanged as the strip oscillation frequency increases.
The cooling capacity of strip gradually increases with an increment in the oscillation frequency. As feeding strip oscillation frequency increases, the area of the low‐liquid‐fraction region gradually increases, which is beneficial in promoting central nucleation and grain growth during the actual production process.
In this paper, the effect of strip spacing on the aerodynamic performance of a high-speed pantograph with a double-strip is numerically studied using a shear stress transport turbulence model. Seven ...different strip spacings varied from 100 to 700 mm are considered. The errors in pantograph resistance between numerical simulation and wind tunnel test are within 5% in both knuckle-downstream and knuckle-upstream operating conditions. The drag and lift forces of the strip increase with the strip spacing when the train's running speed is 350 km/h. By considering the two strips individually, it is interesting to find that the lift force on the first strip tends to be stable as the spacing reaches up to 600 mm in both operating conditions, whereas the lift force on the second strip increases continuously with the spacing in the whole range of 100-700 mm. Furthermore, the aerodynamic coefficient of the strip is a nearly constant value at different running speeds, which increases with the strip spacing, suggesting that the relationship between the aerodynamic forces and the spacing of strips obtained in the current study can be extended to any speed level in the range of 200-350 km/h.
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