work addresses specific fundamental and methodological issues regarding the applicability Fracture Mechanics (FM) testing schemes to polymer open-celled cellular solids with controlled architecture, exhibiting an elastic-plastic response and with pronounced structural heterogeneity at the cell-scale. Acrylonitrile-Butadiene-Styrene (ABS) model structures were manufactured by Fused Deposition Modeling (FDM), and their mode-I fracture response investigated. Structures with different porosity degrees (from approximate to 20% to approximate to 70%) were examined, initiation fracture toughness (J-integral) data determined. Different modes of mechanical macro-confinement experienced by the circular cross-section beam-like structural element were noticed, able to drive a transition from true cellular to solid containing isolated pores.

In this work, Acrylonitrile-Butadiene-Styrene model structures were manufactured by FDM, and their mechanical behaviour investigated under compression, both at small and at large strains. The structure design strategy adopted, based on the use of circular cross-section beam-like elements formed under controlled conditions, led to obtain open-cell structures (with a porosity degree of ≈ 65%) composed of unit cells with different shapes and dimensions assembled to form regularly repeating patterns. The stress-strain behaviour, from cube- and prism-shaped specimens with different sizes and loaded along different directions, was discussed in the light of the outcomes from (i) cyclic compression experiments and (ii) morphological analyses of cryogenic fracture surfaces of specimens compressed at high strain levels. The response along the 3D-stacking direction was traced back to the elastic-plastic case, with non-recoverable strain starting to accumulate between 3% and 5% strain and structure densification starting below 20%. The specimen size effects turned out to be little pronounced. Slightly higher levels of stiffness and strength were measured for the largest cube. This result was discussed on the basis of the peculiar morphology of the structure examined.

Purpose This study investigates the relation between ESG-driven investment strategies and the performance of infrastructure funds. More specifically, this study examines the impact of the different dimensions – environmental (E), social (S) and governance (G) – of the ESG profile of infrastructure funds on their performance. Design/methodology/approach To study the risk-return properties of infrastructure funds and the relationship with their ESG profiles, an econometric analysis is conducted, based on a sample of 180 listed, ESG-oriented infrastructure funds identified through Refinitiv Eikon. Findings The results show that infrastructure funds with more solid environmental investment policies experience a lower performance, while those with a stronger social orientation yield a superior performance. Governance-related investment policies seem trivial in determining the performance of these funds. Further analysis shows that ESG controversies have a negative impact on infrastructure funds' performance, whereas Emissions and Resource Use scores, both proxying for different elements under the environmental pillar, have opposite signs. Finally, the Community score has a positive impact on funds' performance consistent with the positive impact of the social pillar score. The study also provides a number of sub-sample analyses to shed light on the conditions under which each pillar has significant impact on funds’ performance. Practical implications First, infrastructure funds should choose the composition of their portfolio holdings in a way that the total return is not penalized by the prevalence of the tricky E aspects (compliance with environmental regulations) over the main benefits of the S dimension. Second, fund managers need to bet on infrastructures with an expected impact on the social pillar dimension such as those aimed at promoting the wealth of the local communities (e.g. hospitals, schools). Third, to strengthen the fund's social dimension, fund managers must increase the dollar amount of the assets under management to count on a higher firepower. Originality/value This study makes three contributions to literature. First, the ESG profiles of the infrastructure funds operating both at local and global level and their relationship with annual performance are studied. Second, the different dimensions of the ESG profile of infrastructure funds are investigated by measuring their impact on performance. Third, the study sheds light on some detailed but relevant aspects of this phenomenon by analyzing the breakdown of the ESG profile of infrastructure funds into four sustainability sub-scores capturing their efforts to reduce CO2 emissions, the use of polluting materials and to influence local communities as well their exposure to the risk of litigation due to the occurrence of ESG controversies. This study addresses the extent to which the adoption of ESG investment policies by the infrastructure funds have an impact on their performances.

In this work, the mechanical behaviour of cancellous bone tissues used for the manufacturing of commercial heterologous bone grafts was investigated both at small and at large strains. Three different tissues were examined. They were obtained from equine bones after a specific proprietary enzymatic-based treatment aimed at achieving perfect biocompatibility while preserving the collagenous part. Two tissues had the mineral content of the bones of origin (femur, humerus), whereas the third was markedly demineralized (femur). The response at small strains and at failure was studied by means of monotonic compression tests in quasi-static conditions. Stiffness and strength turned out to be governed by the apparent density of the tissue, with specimen size and geometry, and tissue macro-structural characteristics, only playing a secondary role. A ductile- and a brittle-like failure was exhibited by the demineralized tissue and the non-demineralized ones, respectively. The large deformation behaviour was studied by means of cyclic compression tests, which clearly highlighted the occurrence of plasticity (for strains higher than ≈1.9%), and allowed to study the strain accumulation processes, at the macromechanical level. More in-depth microstructural analyses were carried out on the demineralized tissue. Flexural tests were also performed.

The focus of this work is on the characterization of hydrophobically-modified polyethylene glycol hydrogels, to be used as drug delivery systems, by means of the combined used of rheology and low field Nuclear Magnetic Resonance. Indeed, these two techniques allowed understanding how the transient physical bonds deriving from hydrophobic association superimpose to the pre-existing covalent bonds. We found that the improvement of physical bonds can be achieved not only by increasing the content of hydrophobic segments but also by using thermal treatments after hydrogel preparation. Moreover, we proved the reliability of an overall interpretative model linking the dependence of the shear modulus and the average magnetic relaxation time. Finally, we proposed a new mathematical approach for the determination of the magnetic relaxation spectrum. This approach reduced the computational heaviness of the procedure and allowed to easily discern the different contributes nested in the overall magnetic relaxation spectrum, an aspect that the traditional approach cannot provide directly.

Retentive drug delivery systems (DDSs) are intended for prolonged residence and release inside hollow muscular organs, to achieve either local or systemic therapeutic goals. Recently, formulations based on shape memory polymers (SMPs) have gained attention in view of their special ability to recover a shape with greater spatial encumbrance at the target organ (e.g., urinary bladder or stomach), triggered by contact with biological fluids at body temperature. In this work, poly(vinyl alcohol) (PVA), a pharmaceutical-grade SMP previously shown to be an interesting 4D printing candidate, was employed to fabricate expandable organ-retentive prototypes by hot melt extrusion. With the aim of improving the mechanical resistance of the expandable DDS and slowing down relevant drug release, the application of insoluble permeable coatings based on either Eudragit® RS/RL or Eudragit® NE was evaluated using simple I-shaped specimens. The impact of the composition and thickness of the coating on the shape memory, swelling, and release behavior as well as on the mechanical properties of these specimens was thoroughly investigated and the effectiveness of the proposed strategy was demonstrated by the results obtained.

Our empirical analysis of 403 acquisitions completed globally between 2007 and 2015 uses a holistic approach to explain the key determinants of premia paid by acquirers, addressed by distinct literature streams. Our results show that overconfident, cash-generating acquirers overpay the targets. Higher premia are justified for larger-sized, high-growth targets, nonconglomerate acquisitions, and when the consideration is paid in stock. Acquirers embed expected operating synergies in premia offered to target shareholders. However, while cost-cutting synergies, more reliably achieved in post-merger integration, are easy to disclose and price, revenue enhancement synergies, requiring exceptional managerial capabilities, are of longer-term nature but more uncertain, thus leading acquirers to precautionarily withhold them in premium pricing. Financial synergies, arising from combining weakly or negatively correlated businesses, are not typically priced upfront.

Profiting from innovation typically involves a choice between commercializing a patented technology in the product market to exploit proprietary advantage (i.e., competition) or licensing the techn...

This article aims to investigate the factors that most influence the yields of public sector and corporate green bonds besides those conveyed by the conventional finance theory (e.g., rating, volatility, maturity). To accomplish that, we first develop a theoretical framework that postulates the negative relationship between the size of the underlying project financed by a green bond issuance, the use of the ESG metrics to quantify such impact, as well as the positive relationship between the risk of greenwashing practices by the issuer, and the yield to maturity of the green bond. We then provide an empirical validation of our conceptual framework by estimating multiple regression models applied to two distinct samples of public and corporate green bonds issued globally in the 2012–2020 period. The reliability of our results is confirmed by further exploring the effects of some key determinants on the yield spread of green versus comparable ordinary bonds of corporate issuers. Our findings corroborate our theoretical predictions showing that investors are inclined to accept lower returns in exchange for contributing to the funding of infrastructure projects with greater impact on the sustainability of target communities or territories and require higher premia as a form of compensation when being exposed to higher risk of greenwashing by issuers. At corporate level, greenwashing risk is higher among manufacturing (rather than services) firms but more pronounced in the financial sector. At public level, greenwashing strategies may be more easily pursued by multinational or sovereign issuers rather than local governments as the former's greater distance from communities enables them to elude investors' controls. Important recommendations are drawn for investors, rating agencies, and policymakers.

This work reports on a novel method to synthesize hydrophobically-modified hydrogels by curing epoxy monomers with amines. The resulting networks contain hydrophilic poly(ethylene glycol) (PEG) segments, poly(propylene glycol) (PPG) segments, and C18 alkyl segments. By varying the content of C18 segments, networks with different hydrophilic-lipophilic balance (HLB) are obtained. All networks show an amphiphilic behavior, swelling considerably both in organic solvents and in aqueous media. In the latter they display a thermosensitive behavior, which is highly affected by the network HLB and the pH of the solution. A decrease in HLB results in an increment of the polymer weight content (wp) due to hydrophobic association. Furthermore, a reduction in HLB induces a remarkable increase in initial modulus, elongation at break and tensile strength, especially when wp becomes greater than about 10%. Low field nuclear magnetic resonance (LF-NMR) experiments evidence that, when HLB decreases, a sudden and considerable increase in hydrogel heterogeneity takes place due to occurrence of extensive physical crosslinking. Available data suggest that in systems with wp ≳ 10% a continuous physical network superimposes to the pre-existing chemical network and leads to a sort of double network capable of considerably improving hydrogel toughness.

The present paper aims at developing an integrated experimental/computational approach towards the design of shape memory devices fabricated by hot-processing with potential for use as gastroretentive drug delivery systems (DDSs) and for personalized therapy if 4D printing is involved. The approach was tested on a plasticized poly(vinyl alcohol) (PVA) of pharmaceutical grade, with a glass transition temperature close to that of the human body (i.e., 37 degrees C). A comprehensive experimental analysis was conducted in order to fully characterize the PVA thermomechanical response as well as to provide the necessary data to calibrate and validate the numerical predictions, based on a thermo-viscoelastic constitutive model, implemented within a finite element framework. Particularly, a thorough thermal, mechanical, and shape memory characterization under different testing conditions and on different sample geometries was first performed. Then, a prototype consisting of an S-shaped device was fabricated, deformed in a temporary compact configuration and tested. Simulation results were compared with the results obtained from shape memory experiments carried out on the prototype. The proposed approach provided useful results and recommendations for the design of PVA-based shape memory DDSs.

In this work, the moldability via micro-injection molding (mu IM) of nano-filled polyamide 6 (PA6) based systems and the microstructural characteristics of the micro-injected parts were investigated and compared to those observed via traditional injection molding (IM). Two types of nano-fillers, different in nature and geometry, were examined, namely carbon nanotubes and silicate layers. The presence of nano-fillers did not impair the mold replication capability of PA6 in the mu IM process. A micro-rib and a standard dumbbell specimen for tensile tests were used as reference micro- and macro-injected part, respectively. Transmission Electron Microscopy, Wide and Small Angle X-ray Scattering and Differential Scanning Calorimetry analyses showed that, due to the different thermomechanical histories during mu IM and IM, the micro- and the macro-parts have different microstructures, influenced also by the filler type. Both nano-filler dispersion and PA6 crystallinity were influenced.

Fracture mechanics are of high interest for the engineering design and structural integrity assessment of polymeric materials; however, regarding highly ductile polymers, many open questions still remain in terms of fully understanding deformation and fracture behaviors. For example, the influence of the constraint and specimen size on the fracture behavior of polymeric materials is still not clear. In this study, a polymeric material with an elastic plastic deformation behavior (ABS, acrylonitrile butadiene styrene) is investigated with regard to the influence of constraint and specimen size. Different single-edge notched bending (SENB) specimen sizes with constant geometrical ratios were tested. The material key curve was used to investigate differences in the constraint, where changes for small and large specimen sizes were found. Based on a size-independent crack resistance curve (J–R curve), two apparent initiation parameters (J0.2 and Jbl) were determined, namely, the initiation parameter Jini (based on the crack propagation kinetics curve) and the initiation parameter JI,lim (based on an ESIS TC 4 draft protocol). It was found that J0.2 and Jbl could be used as crack initiation parameters whereby Jini and JI,lim are indicative of the onset of stable crack growth.

In marketing, significant attention has been devoted to the study of drivers and outcomes of strategic flexibility drawing on real options theory. However, research that quantifies the specific value of flexibility reflected in a bundle of strategic real options is lacking. To remedy this gap, we develop a real options-based framework that takes account of brand expansion and extension options to value brand equity and retailer growth strategies. We show how to value the bundle of strategic real options associated with a flexible marketing strategic vision and how to assess the growth strategies related to the corporate brand of an international retailer. We apply our method to estimating the brand equity of Starbucks both under growth and adversity conditions. The results reveal that our method can more reliably incorporate the growth potential of the brand under uncertainty conditions. Comparisons with other brand valuation approaches are discussed. Our study helps clarify the links among management's strategic plans, brand-based marketing strategies and share price, and allows to better monitor the impact of retailer strategic choices on long-term brand equity value. (c) 2021 New York University. Published by Elsevier Inc. All rights reserved.

Scaffolds are structures used for tissue engineering. Their size, shape and geometry are customized according to the patient pathology. A deep knowledge of their properties is essential for a correct design. This work aims at studying the size effect on scaffold-like structures manufactured by Fused Deposition Modeling, analyzing the relationship between the basic mechanical properties and the structure size. Compression tests of porous specimens, made of polylactide, with different heights have been done and, while the elastic modulus appears to be strongly affected by the size of the 3D specimens, the strength has shown to be intrinsic to the structure.

Scaffolds are structures used to support the growth of cells in order to replace damaged parts of tissues. They are typically simple structures with a porous arrangement, which allows cell adhesion, but also the flow of the biological fluid. The scaffold geometry and structure are, however, defined by the specific application and customized according to the pathology and the patient. Based on their functions, scaffolds are characteristically made of biocompatible and often biodegradable materials. A deep knowledge of the properties of the scaffold, and their peculiarities, is essential for a correct design. This work aims at analyzing whether the mechanical behavior of a typical scaffold structure could be described by referring to properties intrinsic to the system (independent on the geometry/size), or a geometry/size dependence should be taken into account. Only in the former case, the structure could be treated as an effective "3D material", so that the scaffold design could be easily produced and its performance predicted. In order to explore this aspect, scaffold-like structures made of poly(lactic acid) have been manufactured using a Fused Deposition Modelling 3D printing machine. Several specimens with different sizes have been fabricated and their mechanical stiffness and strength measured. The results show that concerning the mechanical strength the structure behaves as a "3D material", whereas for the stiffness a size dependence is observed.

Round-robin (RR) tests carried out under the direction of the Technical Committee 4, “Polymers, Polymer Composites and Adhesives,” of the European Structural Integrity Society (ESIS TC4) showed that the multispecimen methodology employed for the construction of the crack growth resistance curve (J vs crack extension, Δa) of polymers often does not provide reliable data because of the uncertainties associated with the measurement of Δa. With this in mind, the ESIS TC4 attention has been more recently focused on the analysis of a testing scheme based on the load separation criterion, which does not require the measurement of Δa. With the aim to employ this new approach into a standardized procedure, the degree of reproducibility of the results obtainable with the application of this testing scheme to ductile polymers has been assessed by means of multilaboratory RR testing exercises that started in 2011. An ESIS TC4 reference draft protocol was prepared and 10 laboratories participated in the RR activities. The present work describes the load separation criterion-based testing procedure recently examined by ESIS TC4 and gives a summary of the results obtained in the RR activities, which appear encouraging.

The Technical Committee 4, "Polymers, Polymer Composites and Adhesives", of the European Structural Integrity Society (ESIS TC4) developed a draft protocol based on the load separation criterion to determine two fracture parameters (an initiation parameter, JI,lim, and a crack growth parameter, ms) without the need to measure the crack growth (Δa). This is especially beneficial, since the measurement of Δa is prone to errors. The developed testing scheme displays promising results, as shown in a round-robin testing exercise. To further push this testing scheme, it is necessary to verify the specimen size scaling possibility. Hence, in this work, single edge notched in bending (SE(B)) specimens with different sizes, but geometrically similar, were manufactured. ESIS TC4 testing scheme was successfully applied to specimens with the different sizes, and data of JI,lim and ms were obtained. The observed effect of the specimen size on the aforementioned fracture parameters is presented and discussed.