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In this study, we designed and synthesized a series of norbornene‐furan functionalized benzoxazine monomers (HPAP‐fa, HPAMP‐fa, and HPTM‐fa) by regulating the bridge length in benzoxazine structure in order to improve the comprehensive performance of norbornene‐furan functionalized benzoxazine system. This research systematically examined the impact of flexible segments on the structural information, polymerization behaviors, thermal stability, and flame retardancy of resulting polybenzoxazines. Initially, the structural characteristics of benzoxazine were confirmed through nuclear magnetic resonance, Fourier‐transform infrared (FT‐IR), and HR‐MS. Subsequently, the polymerization mechanisms of each benzoxazine monomer were investigated utilizing differential scanning calorimeter and in situ FT‐IR analyses. Finally, the thermal stability and flame‐retardant properties were investigated by TGA and micro‐combustion calorimetry measurements. Consequently, HPAP‐fa exhibited the lowest polymerization temperature and the corresponding poly(HPAP‐fa) showed very high thermal stability (Td5 of 392°C and Td10 of 437°C) as well as excellent flame retardancy (HRC of 83.7 J g−1 K−1), which shows a significant improvement compared to poly(HPTM‐fa). As a result, the modulation of bridge segments within the monomer represents a viable approach towards enhancing the holistic efficacy of norbornene‐furan functionalized benzoxazine systems. [ABSTRACT FROM AUTHOR]

In recent years, Topology Optimization (TO) gained interest in the scientific community. It assists in finding the best arrangement of material in a design volume. The classical approach named "Solid Isotropic Material with Penalization" (SIMP) associates a fictitious density to each finite element in the domain. While SIMP is described as an implicit approach which can lead to problems with dimensionality of variables, explicit methods adopt a geometric projection of simple elements (eg.: bars) to reduce the number of design variables. This simplifies the geometric interpretation of the optimal architecture. The major explicit methods were recently unified into a general framework, Generalized Geometric Projection (GGP). Currently it is quite challenging to take into account manufacturing constraints in the topology optimization design phase. Therefore this paper presents an application of the GGP Method to the design of products made by Additive Layer Manufacturing (ALM). Every printed layer constitutes a geometric element, involving design variables relative to position and width. Specific constraints of ALM, including bridge length and overhang angle, can be easily monitored by exploiting the geometric features of the combined elements. Examples in two dimensions will be reported, analyzing two academic benchmark problems. A comparison to other proven techniques is also detailed. An mean difference of 7.7% is observed for solutions with only overhang angle constraint, while a mean difference of 11% is observed for solutions with overhang angle and bridge length constraint. The presented work integrates design and manufacturing, directly identifying the path of the printed layers. [Display omitted] • Single framework that includes most of the 3D printing geometric constraints. • Includes print orientation, overhang angle and bridge length. • Unique geometric primitive to mimic additive layer manufacturing processes. • Combination of topology optimization and print layer optimization (in 2D only). • Also provides optimized print direction and print height per component. • Easy parametrization of hyperparameters to obtain a range of solutions. [ABSTRACT FROM AUTHOR]

Knowledge of dependence between the length of the bridge and parameters which are defining the costs for its production can be extraordinary valuable for making decisions during planning, procurement or any other inhouse processes of manufacturers of this equipment. This article is expressing graphical and functional dependence between the bridge length and the basic parameters which are defining manufacturing costs of the bridges. Presented functions allow to predict parameters defining manufacturing costs for bridges which are out of the scope of this article also. [ABSTRACT FROM AUTHOR]

While both risk-taking and avoidant behaviors are necessary for survival, their imbalanced expression can lead to impulse-control and anxiety disorders, respectively. In laboratory rodents, the conflict between risk proneness and anxiety can be studied by using their innate fear of heights. To explore this aspect in detail and investigate venturesome behavior, here we used a “Himalayan Bridge,” a rat-adapted version of the suspended wire bridge protocol originally developed for mice. The apparatus is composed of two elevated scaffolds connected by bridges of different lengths and stability at 1 m above a foam rubber-covered floor. Rats were allowed to cross the bridge to reach food, and crossings, pawslips, turnabouts, and latencies to cross were measured. Given the link between risky behavior and adolescence, we used this apparatus to investigate the different responses elicited by a homecage mate on the adolescent development of risk-taking behavior. Thus, 24 wild-type (WT) subjects were divided into three different housing groups: WT rats grown up with WT adult rats; control WT adolescent rats (grown up with WT adolescents), which showed a proclivity to risk; and WT rats grown up with an adult rat harboring a truncated mutation for their dopamine transporter (DAT). This latter group exhibited risk-averse responses reminiscent of lower venturesomeness. Our results suggest that the Himalayan Bridge may be useful to investigate risk perception and seeking; thus, it should be included in the behavioral phenotyping of rat models of psychiatric disorders and cognitive dysfunctions.

While both risk-taking and avoidant behaviors are necessary for survival, their imbalanced expression can lead to impulse-control and anxiety disorders, respectively. In laboratory rodents, the conflict between risk proneness and anxiety can be studied by using their innate fear of heights. To explore this aspect in detail and investigate venturesome behavior, here we used a "Himalayan Bridge," a rat-adapted version of the suspended wire bridge protocol originally developed for mice. The apparatus is composed of two elevated scaffolds connected by bridges of different lengths and stability at 1 m above a foam rubber-covered floor. Rats were allowed to cross the bridge to reach food, and crossings, pawslips, turnabouts, and latencies to cross were measured. Given the link between risky behavior and adolescence, we used this apparatus to investigate the different responses elicited by a homecage mate on the adolescent development of risk-taking behavior. Thus, 24 wild-type (WT) subjects were divided into three different housing groups: WT rats grown up with WT adult rats; control WT adolescent rats (grown up with WT adolescents), which showed a proclivity to risk; and WT rats grown up with an adult rat harboring a truncated mutation for their dopamine transporter (DAT). This latter group exhibited risk-averse responses reminiscent of lower venturesomeness. Our results suggest that the Himalayan Bridge may be useful to investigate risk perception and seeking; thus, it should be included in the behavioral phenotyping of rat models of psychiatric disorders and cognitive dysfunctions. [ABSTRACT FROM AUTHOR]

This study investigated the change of stress with crack development, using the numerical code RFPA 3D , so as to understand the crack coalescence mechanisms occurring within a heterogeneous solid containing multiple holes loaded in a state of uniaxial compression. A full discussion is presented on a statistical analysis of observed microcracks data, and on the appropriate parameter selection based on those microcrack statistics. The simulated peak stress results and coalescence patterns using the selected parameters were found to closely resemble previous experimental observations. A full investigation and discussion of the stress distributions around holes during the crack growth and coalescence processes is presented for heterogeneous sample cases. Under applied loading, crack initiation, growth direction and coalescence pattern are strongly influenced by the shape of the interaction tensile zone formed between holes. Acoustic emission (AE) analysis in relation to the numerical simulations indicates that no case of pure tensile crack coalescence occurs between holes. Three modes of coalescence are classified: T s mode (tensile mode coalescence with shear), M T mode (mixed mode coalescence with tensile mode dominant) and M mode (mixed mode coalescence). The crack coalescence mechanisms and patterns were further investigated by changing the parameters of normalized bridge length ( d/r ), bridge angle β and number of holes. A precise crack coalescence criterion is proposed. [ABSTRACT FROM AUTHOR]

Understanding the mechanical behaviour of jointed rock particularly under uniaxial compression is so important for an appropriate design of structures on or within a rock mass. Jointed rocks may consist of persistent or non-persistent joints. Typically, the persistent joints can dominate the whole mechanical behaviour of jointed rocks while the effects of non-persistent joints on the rock masses require careful consideration during the characterisation process. Majority of the earlier studies on the non-persistent jointed rocks have included the joints with open smooth surfaces while the behaviour of jointed rocks with non-persistent rough joints has been explored very limitedly. Therefore, in this study, a number of artificial jointed rocks with non-persistent rough joints were tested under uniaxial compression. With the aid of 3D printing technology a wide range of joint roughness has been accommodated inside the artificial samples. The joints were parallel or coplanar. The influences of four different parameters including Joint Roughness Coefficient, bridge length, bridge angle and joint angle on the uniaxial compressive strength, the deformation modulus and the crack coalescence stress of jointed rocks were investigated through multivariate statistical analysis using Response Surface Methodology. In total, 30 experiments were conducted and the resulting failure patterns were classified into six different categories based on their crack coalescence conditions. A number of samples revealed a specific failure pattern known as " fish eye " due to the development of " asperity interlocking cracks " which were associated with the high range of joint roughness. From Response Surface Methodology it was found that all the four parameters had individual and interactive effects on the uniaxial compressive strength and the deformation modulus of jointed rock. Also, it was concluded that the overall mechanical behaviour of a jointed rock with non-persistent rough joints is mainly controlled by the joint angle under uniaxial compression. • Conduction of a set of uniaxial compressive tests on the jointed rock-like material with non-persistent rough joints • Characterisation of crack coalescence behaviour of non-persistent jointed rocks • Multivariate statistical analysis of mechanical behaviour of jointed rocks based on Response Surface Methodology [ABSTRACT FROM AUTHOR]