Stagnant Stage Research Articles

The influence of organizational factors on board roles

PurposeUsing a contingency approach, the purpose of this paper is to study how organizational factors (such as the organizational life cycle, firm size, firm ownership concentration and firm technology) determine the relative importance of the monitoring and provision of resources roles provided by board members.Design/methodology/approachThis paper highlights the importance of contingency factors in carrying out board’s roles using a sample of 579 European firms registered in the STOXX Europe 600 index. The authors used a longitudinal analysis for the period from 2002 through to 2011.FindingsThe results show that the monitoring role is more relevant for companies that are large, are operating at the mature and stagnant stages, have a dispersed ownership and are low-technology. However, the provision of resources role is more relevant for companies that are in the growth and stagnant stages, and have a concentrated ownership.Originality/valueThe traditional analysis that relates the board’s structure and composition to the board’s roles focuses on determining what board should be the best. It plays little attention to analyzing which organizational factors affect the importance and presence of monitoring or resource dependence roles. In this regard, this work adds significant insights to agency theory and resource dependence theory as, with a contingency framework, the research aims to find what functions the board needs to develop in order to get better firm performance.

Multi-phase-field simulation of cyclic phase transformation in Fe-C-Mn and Fe-C-Mn-Si alloys

The stagnant and inverse transformation stages during cyclic phase transformation in the two-phase region “ferrite+austenite” (intercritical region) of Fe-C-Mn and Fe-C-Mn-Si alloys were investigated using the non-equilibrium multi-phase-field (NEMPF) model, i.e. an MPF model with finite interface dissipation. We showed that if we used large interfacial permeability parameters that characterize the partitioning rate of solute atoms in the ferrite/austenite interface, the NEMPF model predicted the same transformation behavior as that simulated using the MPF model based on the assumption of the parallel tangent law. The simulation demonstrated that the inverse transformation stage, in which ferrite-to-austenite transformation proceeds despite decreasing temperature, could be naturally described by the NEMPF model coupled with the CALPHAD-based thermodynamic database. This study also elucidated a switching of the polarities of Mn and Si spike formed at the ferrite/austenite interface governed the driving force of the austenite-to-ferrite transformation and caused the stagnant stage where the phase transformation was suppressed. Furthermore, the impact of the amount of Mn and Si atoms on the stagnant stage length was examined using the NEMPF model. The simulations revealed that increasing the concentration of Mn and Si extended the stagnant stage, with a more pronounced effect with Mn rather than Si atoms.

Developmental stages and important periods of probability cognition in 6 to 14 year-old students

This study chose 906 students of 6 to 14 years of age and focused on the developmental stages and important periods of probability cognition. The study shows that probability cognition of students aged 6-14 experiences the following 5 stages: slow development stage I (6-7 years old), quick development stage I (8-9 years old), slow development stage II (10 years old), quick development stage II (11-12 years old) and stagnant stage (13-14 years old). Additionally, there are two important periods in students’ cognitive development: 8-9 years old is the first period and 11-12 is the second. Even at the highest development stage, students can just understand the number representation, probability distribution and fraction representation while ca not reach the mastery level, which suggests the limitation of students’ probability cognition. Accordingly, curriculum should take students’ cognitive development level into account and set reasonable cognitive objectives.

In-situ investigation of quenching and partitioning by High Energy X-Ray Diffraction experiments

We report the first ultra-fast time-resolved quantitative information on the quenching and partitioning process of conventional high strength steel by in-situ High Energy X-Ray Diffraction experiment. The time and temperature evolutions of phase fractions, their carbon content and internal stresses were determined. The austenite to martensite transformation below Ms is followed by a stagnant stage during which microstructural state remained unchanged. Afterwards, a fast kinetics of carbon enrichment of austenite during the partitioning step at 400°C is highlighted. The analysis proposed supports the carbon diffusion from martensite to austenite as the main mechanisms responsible for this enrichment.

Phase Field Modeling of Cyclic Austenite-Ferrite Transformations in Fe-C-Mn Alloys

Three different approaches for considering the effect of Mn on the austenite-ferrite interface migration in an Fe-0.1C-0.5Mn alloy have been coupled with a phase field model (PFM). In the first approach (PFM-I), only long-range C diffusion is considered while Mn is assumed to be immobile during the phase transformations. Both long-range C and Mn diffusions are considered in the second approach (PFM-II). In the third approach (PFM-III), long-range C diffusion is considered in combination with the Gibbs energy dissipation due to Mn diffusion inside the interface instead of solving for long-range diffusion of Mn. The three PFM approaches are first benchmarked with isothermal austenite-to-ferrite transformation at 1058.15 K (785 °C) before considering cyclic phase transformations. It is found that PFM-II can predict the stagnant stage and growth retardation experimentally observed during cycling transformations, whereas PFM-III can only replicate the stagnant stage but not the growth retardation and PFM-I predicts neither the stagnant stage nor the growth retardation. The results of this study suggest a significant role of Mn redistribution near the interface on reducing transformation rates, which should, therefore, be considered in future simulations of austenite-ferrite transformations in steels, particularly at temperatures in the intercritical range and above.

Austenite Evolution and Solute Partitioning during Thermal Cycling in the Intercritical Range of a Medium-Mn Steel

The evolution of austenite fraction and the associated solute partitioning during the intercritical annealing of medium-Mn steels are of great importance for austenite stabilization and the mechanical performance of this class of steels. In the present work, a 4.5Mn steel is subjected to a cyclic treatment and the evolution of the austenite fraction is measured with dilatometry. The evolution of austenite fraction and solute partitioning are simulated for a case where the starting time of the cyclic treatment is well before the equilibrium fractions have been established in the respective isothermal intercritical treatment. The evolution of austenite during thermal cycling in the intercritical range comprises of forward, inverse, and stagnant stages. The fraction of austenite formed decreases in each successive cycle while the kinetics of the evolution of austenite is controlled by the Mn diffusion in ferrite. Partitioning of Mn and C takes place from ferrite to austenite during the cyclic transformation. Due to the low diffusivity in austenite, wells form in the composition profiles in austenite of both Mn and C. These wells are the locus of the interfacial compositions of austenite, corresponding to the variation of the local equilibrium conditions during the thermal cycle.

Geostatistical modeling for fine reservoir description of Wei2 block of Weicheng oilfield, Dongpu depression, China

The Wei2 block of Weicheng oilfield is characterized by complicated structure mainly caused by high degree of fault development. Multiple reservoir types are found in this block and the reservoir heterogeneity is severe. The oil and gas reservoirs have already stepped into the stagnant stage of a great water-cut degree together with a rapid production decline rate. Thereby, both stabilizing the oil and gas production and optimizing adjustment for further exploitation make it urgent for geomodelers to build a useful model to predict the inter-well parameters and the distribution of the remaining oil and gas. A three-dimensional geological model established with the help of stochastic modeling technique may provide a perfect window and carrier for fine structure interpretation and reservoir heterogeneity description, compared with a traditional two-dimensional model. Hence, based on stratigraphical layering points, significant surfaces and fault points as well seismic interpretation, an integrated structure model is developed. Using the truncated Gaussian simulation and taking the existing geological maps as references, the sedimentary microfacies model was successfully constructed. Through the use of sequential Gaussian simulation method and the facies-controlled modeling method, the reservoir physical properties are populated. Meanwhile, the comparison between facies-controlled and non-facies-controlled property models indicates that the former is more loyal to previous researching and the representation of heterogeneity is ideal. Finally, the ideas of sample density and reserves fitting are proposed to evaluate the practicability and accuracy of the property models.

Phase-field modeling of cyclic phase transformations in low-carbon steels

A phase-field model has been developed to describe microstructure evolution during cyclic phase transformations for two low-carbon steels (Fe–0.1wt%C, Fe–0.1wt%C–0.5wt%Mn). The austenite–ferrite transformations are assumed to occur under negligible-partition conditions for Mn and only long-range diffusion of carbon is considered. A Gibbs-energy dissipation model has been integrated with the phase-field model to describe the stagnant stages during cyclic phase transformations in the ternary alloy. Experimental results, e.g. the stagnant stages and the cyclic phase transformation kinetics, have been successfully replicated with 2D phase-field simulations.

Option-Based Compensation, Corporate Investment Policy, and Stock Repurchases

:Taking account of the business life cycle, this paper investigates the impact of the proceeds associated with stock option exercises on investment expenditures and stock repurchases. The results reveal that the proceeds associated with option exercises could add internal funds to firms and contribute to investment in research and development and capital expenditures, especially in the growth stage of a firm’s life cycle. This paper also shows the positive relationship between option proceeds and stock repurchases in the stagnant stage of that cycle. The empirical results further suggest that stock repurchases may substitute for dividends. In summary, the paper empirically demonstrates that stock options not only encourage employees to work harder, but also create more funds for the firm.

Normal and Abnormal Grain Growths in BaTiO3 Fibers

The grain growth mechanisms along the BaTiO3 fibers were studied between 1150°C and 1250°C. The normal grain growth always reached a stagnant stage after certain heat‐treatment duration caused by the surface pinning effect. However, the abnormal grain growth (AGG) was not pinned by such surface effect, and can grow continuously. The confined normal grain (or matrix grain) size provides the driving force for AGG. The fiber diameter has an important influence on the grain growth behaviors. Submicrometer fibers have relative small stagnant grain sizes, resulting in large driving force for AGG. Abnormal grain growth occurred below 1200°C in the submicrometer diameter fibers, but was not observed at the same temperature in the fibers with diameter of above 1 μm. Due to the large AGG driving force, large number densities of abnormal grains were observed in submicrometer fibers, resulting in “bamboo‐like” microstructure. Fibers with diameters of 1–2 μm were able to be converted into single crystal fibers up to several tens of micrometers due to the relative small AGG driving forces.

Development of ferrite/bainite bands and study of bainite transformation retardation in HSLA steel during continuous cooling

The development of banded structure in HSLA steel during continuous cooling has been systematically studied using dilatometry and microstructural observations. At low cooling rates ( 10 °C/min), the formation of pearlite is suppressed, and the corresponding microstructure consists of banded ferrite and bainite. Dilatometric analysis indicates that as ferrite and pearlite transformation at low rates (or ferrite transformation at higher rates) completes, Manganese (Mn) and Carbon (C) concentration in austenite can retard the bainitic transformation and result in the transformation stagnancy phenomenon. The magnitude of retardation and the bainite morphology are affected by Mn and C concentration. The increased cooling rate decreases Mn and C content in bainite, and then the length of the stagnant stage decreases and bainite morphology changes from lower bainite to acicular ferrite.

Laser shadowgraphy diagnostics for insulated-ordinary mixed planar wire array Z pinches

A laser shadowgraphy system was built based on a Nd:YAG laser backlight with a half width of 9 ns and a wavelength of 532 nm. It has the capacity of time resolution and integration simultaneously during the laser lighting time by utilizing a streak camera and a commercial digital camera as the image recording devices. Experimental study of the insulated-ordinary mixed planar wire array Z pinches was carried out on the Qiangguang-I facility. Experimental results indicate that the expansion of corona plasma of the insulated tungsten wires is slower than that of ordinary wires over the ablation stage. Average velocities of the insulated wire and the ordinary wire located at the array outmost edge are 1.1×104 m·s-1 and 1.7×104 m·s-1 between t=44 ns and t=56 ns respectively. In the fastest implosion stage of 10 ns just before the stagnant time, the average imploding velocities were 5.5×105 m·s-1 and 9.3×105 m·s-1 respectively for the plasma on the insulted wires side and the ordinary wires side. The duration of stagnant stage on the insulated wires side is 5.9 ns, while it is 9.5 ns on the ordinary wires side. The collision boundary is deflected to the insulated wires side. A similar magneto Rayleigh-Taylor Instability structure can be observed on the both sides at the stagnant time.

Corporate governance and innovative success: An examination of the moderating influence of a firm’s life cycle stage

In this study we examine whether corporate governance influences a firm’s innovative success and if so, how this association is moderated by the life cycle stage of the firm. Innovative success is a broad term and is difficult to measure. Based on Mansfield (1981) we trichotomize ‘innovative success’ into three components, namely, technical (measured by number of patents received), commercial (measured by sales growth) and economic success (measured by Tobin’s Q as based on Mansfield (1981)). We use a sample of electronic firms in Taiwan which invested in research and development covering the years 2001–2009. We find that higher levels of corporate governance have a significant effect on two components of innovative success, namely, patent productivity and a fir m’s value but not on commercial success as measured by sales growth. We also find that the influence of corporate governance on the three components of innovative activity is most pronounced when the firm is in the stagnant stage of its respective life cycle and least pronounced when the firm is in the growth stage. Our study adds to the discussion on the importance of corporate governance by showing that while it has a positive influence on innovative activity, its impact is contingent on the stage of the firm in its respective life cycle.

Experimental Evidence of the Effect of Alloying Additions on the Stagnant Stage Length During Cyclic Partial Phase Transformations

Cyclic phase transformation experiments are performed in a series of Fe-C-xMn, Fe-C-Mn-xNi, and Fe-C-Mn-xCo alloys to study the effect of alloying elements on the length of the stagnant stage during a cyclic partial phase transformation in the austenite–ferrite two-phase region. The length of stagnant stage increases linearly with the increasing Mn or Ni concentration, while Co has no effect. It was experimentally proven that the effects of alloying elements on the length of stagnant stage are additive, and the experimental results matched the predictions of the local equilibrium model very well.

Application of interrupted cooling experiments to study the mechanism of bainitic ferrite formation in steels

New interrupted cooling experiments have been designed to study the kinetics of bainitic ferrite formation starting from a mixture of austenite and bainitic ferrite. It is found that the kinetics of bainitic ferrite formation during the cooling stage is determined by the isothermal holding time. The formation rate of bainitic ferrite at the beginning of the cooling decreases with increasing prior isothermal holding time. An unexpected stagnant stage during the cooling stage appears when the isothermal holding time increases to a critical point. There are two reasons for the occurrence of the stagnant stage: (i) a solute spike in front of the interface; and (ii) kinetic transition. A so-called Gibbs energy balance approach, in which the dissipation of Gibbs energy due to diffusion inside the interface and interface friction is assumed to be equal to the available chemical driving force, is applied to theoretically explain the stagnant stage. A kinetics transition from a fast growth mode without diffusion of Mn and Si inside the austenite–bainitic ferrite interfaces to a slow growth mode with diffusion inside the interface is predicted. The stagnant stage is caused by the transition to a slow growth mode. The Gibbs energy balance approach describes the experimental observations very well.

In situ observation of austenite–ferrite interface migration in a lean Mn steel during cyclic partial phase transformations

High-temperature laser scanning confocal microscopy (HT LSCM) has been applied to investigate the austenite–ferrite interface migration during cyclic phase transformations in situ in a Fe–Mn–C alloy. It has been found that during the cyclic phase transformations the transformation proceeds via the migration of existing austenite–ferrite interfaces. The interfaces migrate in a retraceable way. For the first time, the so–Called stagnant stage has been observed directly. The new in situ observations show that the interface migration rates for interfaces in different grains are comparable with each other prior to soft impingement, while the equilibrium migration distances for different interfaces can be quite different, depending on the local grain size. The average interface velocities as measured by HT LSCM are in very good agreement with the velocities derived from dilatometric data, and those are predicted by a local equilibrium transformation model.

The effect of R&D tax credit on innovation: A life cycle analysis

The purpose of this study is to explore how tax credits for research and development influence innovative activity (as measured by investment in R&D) with emphasis on the moderating role of the firms stage in its respective life cycle. Our sample comprised all electronics firms listed on the Taiwan Stock Exchange and Taiwan’s Over-the-Counter Market fom 2002–2007. Our final sample comprised 943 firm-year observations. We ran regressions and our findings indicate that the R&D tax credit has the greatest impact on innovative activity when the firm is in the stagnant stage and the least impact when the firm is in the growth stage. Our contribution to the extant literature in innovation is severalfold. First, in prior studies, the R&D tax credit is measured as a dummy variable. In this study we use actual R&D tax credit data. Second, prior research examining the association between the R&D tax credit and innovative activity has shown mixed results. We provide an explanation for the inconclusive results by showing that the association is contingent on the stage of the firm in its life cycle. This was not addressed in prior studies. From the public policy standpoint, our findings imply that governments should provide companies with increased tax incentives to stimulate innovative activity, especially when companies are in the stagnant stage in their respective life cycle.

Application of the stagnant stage concept for monitoring Mn partitioning at the austenite-ferrite interface in the intercritical region for Fe–Mn–C alloys

The length of the stagnant stage during the new ferrite growth starting from a mixture of austenite and ferrite has been investigated for a Fe-0.17Mn-0.023C (wt%) alloy. It was found that the stagnant stage depends on the thermal path followed to create the mixture, and deduce that the tie-lines for austenite to ferrite transformation are quite different from those for ferrite to austenite transformation. The length of the stagnant stage is determined by the very local partitioning effect at the interface, and it can be used as a tool to monitor the Mn partitioning.

Analysis of the stagnant stage in diffusional phase transformations starting from austenite–ferrite mixtures

The stagnant stage during the diffusional phase transformations starting from a mixture of austenite and ferrite has been systematically investigated using local equilibrium diffusional transformation models and the cyclic phase transformation concept. The stagnant stage is identified in M contained alloys (M is substitutional alloying element, and the partitioning coefficient of M between austenite and ferrite is not equal to 1, M=Mn, Ni, Cu, Si), and the length of stagnant stage is affected by the concentration of M and partitioning coefficient. There is no stagnant stage in Fe–C and Fe–Co–C alloys. The length of stagnant stages extends with increasing heating and cooling rate during the cyclic phase transformations. The stagnant stage in quaternary alloys was also investigated, and it was found that the effect of substitutional alloying elements on the length of stagnant stage in multi-component alloys seems to be additive.

Interface Motion and Interface Mobility of the Partitioning Phase Transformations in Fe-Mn-C and Fe-C Alloys: A Cyclic Phase Transformation Approach

A cyclic phase transformation concept has been proposed to investigate the growthkinetics of the austenite (γ) to ferrite (α ) and vice versa in Fe-Mn-C and Fe-C alloys. In the caseof cyclic partial transformations in Fe-Mn-C alloys, two new and special stages are observed:a stagnant stage in which the degree of transformation does not vary while the temperaturechanges and an inverse phase transformation stage, during which the phase transformationproceeds in a direction contradictory to the temperature change. The local equilibrium (LE)and paraequilibrium (PE) are both applied to analyzing the new observations. The stagnantstage was found to be caused by the Mn partitioning, while the inverse phase transformationstage was due to equilibrium conditions not being reached at the transition temperatures.A mixed-mode model is applied to simulating the cyclic phase transformation in Fe-C alloy,and it is found that the cyclic phase transformation concept is a very promising method forinvestigating the interface mobility.