Ballistic effectiveness of Zr-containing composite solid propellants as a function of binder nature and mass fraction

This paper considers the effects of binder mass fraction on the properties of energetic formulations based on zirconium and zirconium hydride. These ingredients, replacing aluminum in solid rocket motors with low vehicle performance coefficient, may increase the propellant ballistic effectiveness, thanks to the resulting higher density and notwithstanding their lower specific impulse. The propellant ballistic effectiveness is estimated via the vehicle velocity achieved using the propellant under analysis in a real vehicle. For each specific mission, the binder content can be varied to provide the optimal relationship between energetic and physical-mechanical properties, that is, one may sacrifice energy in favor of rheological and physicomechanical properties (increasing binder mass fraction), or vice versa

How and when do big data investments pay off? The role of marketing affordances and service innovation

Big data technologies and analytics enable new digital services and are often associated with superior performance. However, firms investing in big data often fail to attain those advantages. To answer the questions of how and when big data pay off, marketing scholars need new theoretical approaches and empirical tools that account for the digitized world. Building on affordance theory, the authors develop a novel, conceptually rigorous, and practice-oriented framework of the impact of big data investments on service innovation and performance. Affordances represent action possibilities, namely what individuals or organizations with certain goals and capabilities can do with a technology. The authors conceptualize and operationalize three important big data marketing affordances: customer behavior pattern spotting, real-time market responsiveness, and data-driven market ambidexterity. The empirical analysis establishes construct validity and offers a preliminary nomological test of direct, indirect, and conditional effects of big data marketing affordances on perceived big data performance

Comparison of the Uptake and Metabolism of Retinol Delivered to Primary Mouse Keratinocytes Either Free or Bound to Rat Serum Retinol-binding Protein

Serum retinol-binding protein (RBP) is believed to be responsible for the transport of retinol from its storage site in the liver to vitamin A requiring target cells such as keratinocytes. We have used primary mouse keratinocytes as a model system to compare the uptake and metabolism of [3H] retinol delivered to them either free in solution or bound to RBP. RBP was purified from rat serum, loaded with [3H]retinol, and the [3H]retinol-RBP complex purified by affinity chromatography on human transthyretin-Sepharose. Keratinocytes incubated with either free [3H]retinol or [3H]retinal-RBP complex accumulated [3H]retinol in a time and temperature dependent manner, However, cells incubated with free [3H]retinol acquired 15- to 20-fold more ligand than if the retinol was delivered via RBP. The uptake of free [3H]retinol or [3H]retinol from RBP was not inhibited by excess unlabeled free retinol. The uptake of [3H]retinol from RBP was inhibited by high concentrations of holo-RBP, with half maximal inhibition occurring at 3μM holo-RBP. However, no specific binding of 125I-labeled RBP to monolayers of keratinocytes or membranes prepared from them was found indicating the absence of a high affinity RBP receptor on keratinocytes. Surprisingly, 50% of the [3H]retinol delivered to the keratinocytes during a 30-min uptake period was released from them within 30-min irrespective of whether or not it was initially delivered to them as free [3H]retinol or bound to RBP. The remaining 50% was lost at a much slower rate, but only 20% remained 24-h after delivery. Studies on retinol metabolism demonstrated that 7%12% of the total cell-associated [3H]retinol delivered during a 90-min uptake period was esterified (mostly as retinyl palmitate) whether or not it was given free in solution or bound to RBP

Realising Value from Big Data Technology Adoption: Understanding the Role of Organisational Capabilities in the Affordance Actualization Process

The adoption of big data technologies presents organisations with many value creation opportunities that can transform and improve their business. Much of the research today focuses on big data value creation (what value big data technologies offer), whereas limited research focuses on big data value realisation (how big data value is realized). We aim to fill this research gap by addressing the following research question: how do organisations effectively realize value from the adoption of a new big data technology? We do so by adopting an affordance theory lens and empirically examine the adoption of smart meters (a big data technology) in the UK energy sector. We introduce the concept of actualization enablers, and our findings provide empirically grounded insights into the role of organisational capabilities and actualization enablers in the big data value realization process (affordance actualization). Furthermore, our findings provide important and relevant theoretical and managerial implications

Open strategy and dynamic capabilities: a framework for circular economy business models research

The circular economy has attracted the interest of business leaders, policy makers and academics alike for its potential to contribute to a more resilient, prosperous and resource-efficient economy. The transition towards a circular economy requires new business models that challenge the linear logic of value creation that is still endemic across most industries. In turn, the transition from linear to circular business models involves the rethinking of strategic decision-making processes and the development of new organisational capabilities. This paper addresses these important strategic implications of the emergence and implementation of circular business models. Coupling business models with open strategy and dynamic capabilities, we develop a “three-pronged” strategy framework that advances the emerging field of circular business model research. Our contribution is crystallised into a series of propositions and future research questions for scholars working at the intersection of the circular economy and the strategy literature

Decomposing profile-to-role configurations in R&D-Focused entrepreneurial teams

We draw on social categorization theory to explain how entrepreneurial teams focused on research and development (R&D) are configured to deliver successful new venture performance. Research on entrepreneurial teams tends to aggregate individuals to the team level, which helps distill the effects of complementarities among social categories of team members. Specifically, we examine how scientists and managers apply their unique profiles (i.e., accumulated skills and expertise) to execute their respective roles within entrepreneurial teams engaged in commercial scientific discovery. In line with the entrepreneurial team literature, we distinguish between “focused” and “diversified” social categorizations of principal scientists and managers. As such, we differentiate between individuals’ deep knowledge of a discipline and a background in two professional areas with relative expertise in each, likened to the “jack-of-all-trades”. We analyze how team profile-to-role configurations might result in different new venture outcomes being R&D performance and commercial performance. To examine our models, we use multi-source, longitudinal, secondary data drawn from 153 government-funded research-intensive ventures associated with the National Cancer Institute in the United States (U.S.). Our results reveal differential effects for R&D performance and commercial performance. We find that teams aiming to enhance their R&D performance should seek diversified principal scientists, whereas teams seeking commercial gains should appoint diversified managers. By the same token, diversified team members may bypass their own shortcomings and complement their strengths by attracting team members with focused social categorizations

Maternal vitamin A supplementation increases natural antibody concentrations of preadolescent offspring in rural Nepal

AbstractObjectiveB1a lymphocytes—which constitutively produce most natural antibodies (NAb)—arise from an early wave of progenitors unique to fetal life. Vitamin A regulates early lymphopoiesis. In animals, deficiency during this critical period compromises B1 cell populations. The aim of this study was to investigate the effect of maternal supplementation with vitamin A or β-carotene from preconception through lactation on NAb concentrations of offspring.MethodsParticipants (N = 290) were born to participants of a cluster-randomized, placebo-controlled trial of weekly maternal vitamin A or β-carotene supplementation (7000 μg retinol equivalents) conducted in Sarlahi, Nepal (1994–1997) and assessed at ages 9 to 13 y (2006–2008). Serum retinol was measured by reversed-phase high-performance liquid chromatography at mid-pregnancy and 3 mo of age. Enzyme-linked immunosorbent assay (ELISA) was used to measure children's plasma NAb concentrations at 9 to 13 y.ResultsUnadjusted geometric mean concentrations were 20.08 U/mL (95% confidence interval [CI], 17.82–22.64) in the vitamin A group compared with 17.64 U/mL (95% CI, 15.70–19.81) and 15.96 U/mL (95% CI, 13.43–18.96) in the β-carotene and placebo groups (P = 0.07), respectively. After adjustment, maternal vitamin A supplementation was associated with a 0.39 SD increase in NAb concentrations (P = 0.02). The effect was mediated by infant serum retinol in our statistical models. Although girls had 1.4-fold higher NAb concentrations (P < 0.001), sex did not modify the vitamin A effect.ConclusionsIn an undernourished population, maternal vitamin A supplementation enhanced NAb concentrations of preadolescent children. We posit that this was due to a greater allotment of B1a precursors during fetal life and a sustained higher count of NAb-secreting B1a cells

Radiation Tolerant 3D Laser Scanner for Structural Inspections in Nuclear Reactor Vessels and Fuel Storage Pools

Accurate and timely assessment of displacements and/or structural damages in nuclear reactor vessels' components is a key action in routine inspections for planning maintenance and repairs but also in emergency situations for mitigating consequences of nuclear incidents. Nevertheless, all these components are maintained underwater and reside in high-radiation fields thus imposing harsh operative conditions to inspection devices which must cope with effects such as Cerenkov radiation background, Total Ionizing Radiation (TID), and occlusions in the detectors' field of view. To date, ultrasonic techniques and video cameras are in use for inspection of components' integrity and with measurements of volumetric and surface crack opening displacements, respectively. The present work reports the realization of a radiation tolerant laser scanner and the results of tests in a nuclear research reactor vessel for acquisition of 3D models of critical components. The device, qualified for underwater operation and for withstanding up to 1 MGy of TID, is based on a 515 nm laser diode and a fast-scanning electro-optic unit. To evaluate performances in a significant but controlled environment, the device has been deployed in the vessel of a research reactor operated by ENEA in the Casaccia Research Centre in Rome (Italy). A 3D model of the fuel rods assembly through a cooling water column of 7 m has been acquired. The system includes proprietary postprocessing software that automatically recognizes components of interest and provides dimensional analysis. Possible application fields of the system stretch to dimensional analysis also in spent nuclear fuel storage pools