Incorporation of engineering knowledge into the modeling process: a local approach

Process modelling is the foundation of developing process controllers for monitoring and improving process/system health. Modelling process behaviours using a pure empirical approach might not be feasible due to limitation in collecting large amount of data. Engineering models provide valuable information about processes’ general behaviours but they might not capture distinct characteristics in the particular process studied. Many recent publications presented various ideas of using limited experimental data to adjust engineering models for making them suitable for certain applications. However, the focuses there are global adjustments, where modification of engineering models impacts the entire model-application region. In practice, some engineering models are only valid in a part of experimental data domain. Moreover, many discrepancies between engineering models and experimental data are in local regions. For example, in a chemical vapour deposition process, at high temperatures a process may be described by a diffusion limited model, while at low temperatures the process may be described by a reaction limited model. To address these problems, this article proposes two approaches for integrating engineering and data models: local model calibration and local model averaging. Through the local model calibration, the discrepancies between engineering’s first-principle models and experimental data are resolved locally based on experts’ feedbacks. To combine models adjusted locally in some regions and also models required little adjustments in other regions, a model averaging procedure based on local kernel weights is proposed. The effectiveness of the proposed method is demonstrated on simulated examples, and compared against a well-known existing global-adjustment method.     

Studying the multilevel impact of cohesion versus structural holes in knowledge networks on adaptation to IT‐enabled patient‐care practices

We investigate the impact of cohesion versus structural holes in two different types of knowledge networks—help‐seeking networks and voluntary contribution networks—on adaptation to health IT‐enabled patient‐care practices. In a multimethod study conducted within a large hospital system, qualitative and quantitative data were collected from 806 clinicians working with electronic medical record systems in 27 inpatient patient‐care units. Multilevel analysis of the data revealed that overall network cohesiveness versus location in structural hole positions related to adaptation differently, depending on the type of network. In help‐seeking networks, location in structural hole positions was negatively related to adaptation, while network cohesion had a bell‐shaped curvilinear relationship with adaptation; in voluntary contribution networks, the overall cohesiveness of the network was negatively related to adaptation, but location in structural hole positions was irrelevant to adaptation. Our findings suggest a more nuanced way of monitoring and utilising different sets of informal social interactions at work to maximise employees' adaptation to IT‐enabled work.     

Antifertility agents: 5. Synthesis of 2,2-dimethyl-3,4-diphenyl-5,6-benzochromenes and 1,1-dimethyl-2,3-diphenylphenalenes

3-phenyl-4-(p-(beta-pyrrolidinoethoxy)- HCl, HC1, 2,2-dimethyl-3-phenyl-4(p-(beta-pyrrolidinoethoxy) -phenyl)-5,6-benzochromene-HCl, 1,1-dimethyl-2,3-diphenyl-4-(beta-pyrrolidinoethoxy) -phenalene, and 1,1-dimethyl-2-phenyl-3-(p-(beta-pyrrolidinoethoxy) -phenyl)-4-beta-pyrrolidinoethoxy phenalene were synthesized from 5,6-benzocoumarins. When tested in rats at 10 mc/kg orally for 5 days for antiimplantation activity, they were ineffective.     

Studies on hydride terminated methylhydro-dimethylsiloxane copolymers

Synthesis of hydride terminated methylhydro-dimethylsiloxane copolymers from the hydrolyzates of 10, 20, 30, 50 and 70% vol.-% dichloromethylsilane with dichlorodimethylsilane have been carried out. The copolymers were characterized by IR-and ¹H-NMR-spectroscopy and standard chemical analysis. They were used as curatives for a standard vinyl functional room temperature vulcanizing (RTV) silicone material based on addition cure, and the vulcanizate properties have been evaluated. The copolymers with high hydride content gave better mechanical properties and thermal stability to the vulcanizates.     

Cement Formulations in the Calcium Phosphate H2O–H3PO4–H4P2O7 System

Despite numerous reports of calcium phosphate cement materials, a calcium cement that sets to form a matrix consisting of a pyrophosphate phase has not been reported. The formulation of such a material from the mixture of α-tricalcium phosphate (TCP), β-TCP, or tetracalcium phosphate with a solution containing pyro- and orthophosphoric acid is reported in this study. The effects of liquid and solid compositions on the setting times, compressive strengths and phase compositions of the resultant cements were investigated. It was found that cements could be produced that set to form up to 28 wt% dicalcium pyrophosphate, which appeared by comparison with Rietveld refinement and chemical methods to be entirely amorphous in nature. The solubilities of the different solid components were shown to have a marked effect on the composition of the cements. The strongest cement formulations exhibited compressive strengths comparable with those previously reported in the literature for brushite cements and set within clinically relevant time scales. This class of cement would appear to demonstrate potential as a bone replacement material.     

Algal growth in warm temperate reservoirs: kinetic examination of nitrogen, temperature, light, and other nutrients

Nutrient limited growth of the phytoplankton assemblage in two Texas reservoirs was studied by a combination of nutrient addition experiments and statistical modeling. Dilution bioassays were run to ascertain the qualitative and quantitative patterns in nutrient limitation. Algal growth was frequently and strongly nutrient limited, particularly when temperature was >22°C. By itself, N was more often stimulatory than P, though strong additional enhancement of growth by P and trace nutrients was often detected. Monod growth kinetics indicated that half-saturation constants for N limited growth for the entire algal assemblage were in the range 20–200 μg N/L, relatively high compared to literature values, and increased with increasing temperature. Maximal growth was also an increasing function of temperature. A single temperature-dependent model was fit to the growth dynamics for all experiments showing N-limitation. The model μ=0.0256·T([DIN]/66.0+[DIN]) where μ is specific growth rate (d⁻¹), T is temperature (°C) and [DIN] is dissolved inorganic N (μmol/L) fit the experimental results reasonably well (r²=0.82). However, only a modest predictive power for growth in the controls (our best estimate of growth in situ) was achieved (r²=0.26). Thus, even with unusually detailed, site-specific fitting of model parameters, accurately modeling algal growth in natural ecosystems can remain a challenge.     

Firm valuation effects of the decision to adopt relationally governed business process outsourcing arrangements

Business process outsourcing (BPO) has recently grown in incidence and importance. However, academic research on this phenomenon is sparse. Further, studies on outsourcing have primarily used a transaction cost economics (TCE) lens, largely neglecting other key theoretical explanations of the outsourcing decision and performance. While TCE provides a useful framework, it underemphasises hybrid governance structures that reflect relationships that fall between markets and hierarchies. We examine the decision to adopt relationally governed BPO arrangements and the impact on firm value. We recognise ‘discriminatory alignment’ aspects of governance and argue that the nature of the process itself will influence the value that can be garnered through relational governance. Using secondary data on 298 BPO announcements, we test the proposed model and confirm that a higher level of relational governance adoption strongly enhances firm valuation. This positive valuation impact of relational governance adoption reaches an even higher level in situations of primary processes and processes that have had a presence in the outsourcing organisation. The results emphasise the importance of considering all processes for outsourcing, the critical consideration of relational governance and the importance of planning governance structures that are aligned with the nature and experience with the process being outsourced.     

Organizational readiness for digital innovation: Development and empirical calibration of a construct

The advent and proliferation of digital technologies purport to increase the innovation potential of most organizations. However, approximately 90% of new ideas never convert to new product or service deliveries because of the lack of organizational readiness. This paper conceptualizes a formative multidimensional construct to gauge organizational readiness for digital innovations. Such a construct would facilitate cumulative research on the role of digital innovation, while benchmarking to track organizational readiness. The proposed construct includes 21 measures, categorized under seven subconstructs: resource readiness, IT readiness, cognitive readiness, partnership readiness, innovation valance, cultural readiness, and strategic readiness.     

Atom Probe Tomography of Yttrium‐Doped Barium–Cerium–Zirconium Oxide with NiO Addition

The perovskite ceramic BaCe_0.2Zr_0.7Y_0.1O_3‐δ (BCZY27) with a small addition of NiO has previously been shown to densify at a reasonable sintering temperature while maintaining high protonic conductivity. However, some questions remain regarding the role, location, and resulting phase of the NiO addition. Transmission electron microscopy and atom probe tomography (APT) were used to analyze BCZY27 specimens before and after use as a hydrogen separation membrane. The effects of electrolyte operation on the local chemistry were explored. Grain boundaries were specifically targeted due to their higher energies and importance for overall conductivity. The compositions measured by APT were found to be dependent on the laser energy used for analysis, but conditions were found which gave results reasonably consistent with x‐ray fluorescence results. Specimens before and after electrolytic use showed no measureable difference in the local chemistry. Most grain boundaries exhibited little compositional variation from the bulk material, with only a slight increase in yttrium being apparent. A few grain boundaries had particles 2–15 nm in diameter, which were found by APT to be NiO.     

Drop formation at nozzles submerged in quiescent continuous phase:an experimental study with TBP-dodecane and nitric acid system

Solvent extraction is an important process in the nuclear fuel cycle. Tributyl phosphate(TBP) diluted with dodecane is commonly used as a solvent for extracting heavy metals from nitric acid medium. Studies on hydrodynamics of a single drop, which is the smallest mass transfer entity, are required for better understanding of the complex mass transfer and phase separation phenomena that occur in extraction equipment. In this study, drop formation at nozzles is studied using 30% TBP-dodecane as the dispersed phase and dilute nitric acid as the quiescent continuous phase. Experiments are carried out to determine the drop diameter, jetting velocity, drop detachment height and drop detachment time for various dispersed phase velocities, nozzle diameters(1.91, 3.04, and 4.88 mm), and nitric acid concentrations(0.01, 1, 3 N). Drop formation is captured using high-speed imaging, which enables quantification of drop size, onset of jetting, drop detachment height, and drop detachment time. Experimental data are used to propose correlations for predicting drop diameter and minimum jetting velocity. The correlations are found to be very accurate with average absolute relative errors being 5.23 and 2.97%, respectively.