Using a simple ionic model, the energy necessary to expand a layer structure by a certain distance can be calculated. This has been done for a series of 15 structures including hydroxides, 2:1 and 1:1 structures of various types. Plots of energy versus separation distance show three major groups which have common bonding properties. For large separations, the group with the strongest interlayer bonds contains the brittle micas, the hydroxides, and the 1:1 structures. Intermediate bonding structures are the normal micas and the weakest bonds occur in the zero layer charge 2:1 structures. The relative energies needed for a given separation are not constant so that for small separations the zero layer charge structures such as talc and pyrophyllite are more strongly bonded than the normal micas. These groupings correlate very well with the expandability of the structures by water and other substances. It is proposed that this approach to the study of the layer structures will provide a simple theory explaining the expansion properties of layer silicates.

This paper evaluates the wide discretion afforded to planning decision-makers in England. It does so in respect of a key but often overlooked question in the transition to renewables: whether developers/owners of onshore wind projects should be required to provide a ‘bond’ to ensure decommissioning and site restoration (DSR) occurs. Bonds are financial instruments that evidence ability to fund DSR. They help avoid legacy issues (eg project abandonment) but carry a long-term cost burden for developers/owners. A study of 275 projects elicits three issues. First, a lack of government guidance on bonding, vague ‘threshold’ terms in law and policy and failure of planning decision-makers to consider how others had decided the question result in a lack of markers to inform discretion, with bonds being rare (present in only 15.6% of projects) and their stringency inconsistent. Secondly, this lack of markers legitimises risky, cost-saving practices prohibited in offshore wind, where government guidance informs bonding decisions. Thirdly, reasons for decisions are weak or absent, inhibiting achievement of the justifications for their provision in an administrative context (eg disciplining decision-making). Whilst discretion enhanced capacity to generate electricity from wind through enabling a reduction of market entry costs, assisting movement towards renewable energy targets, it resulted in abandonment risk being ignored. This mirrors strategies adopted elsewhere in England's energy sector, such as coal and oil and gas, where a ‘light touch’ approach to bonding has, traditionally, been deployed to avoid hindering project development.

Despite findings demonstrating the importance of parental present-centered awareness, factors undermining mindful parenting have received less attention. Increasingly, evidence points to parental psychopathology as a salient risk factor for parenting difficulties. Thus, the goal of the present study was to investigate specific dimensions of parental trauma-related distress and general negative affectivity during pregnancy as predictors of mindful parenting during toddler age. Parental psychopathology, parent–infant bonding, and mindful parenting were assessed in a sample of heterosexual couples (N = 159) across four waves of data collection spanning pregnancy to child age two. Data were analyzed using path analysis within a dyadic framework. Results demonstrated the unique impact of maternal trauma-related distress during pregnancy (e.g., intrusions and avoidance) on facets of mindful parenting more than two years later. Further, among both mothers and fathers, general negative affectivity common across internalizing disorders undermined mindful parenting through impaired parent–infant bonding. Findings highlight the need for early intervention efforts that incorporate mindfulness strategies to reduce subthreshold symptoms of prenatal psychopathology, promote healthy bonding, and improve parental awareness and self-regulation, thereby enhancing the overall parent–child relationship.

Although sheep are known to be seasonal breeders and give birth in winter, not all of them follow this trend. A few breeds can be mated and give birth all year round, meaning that mothers and neonates will have to face contrasting climatic conditions. The aim of this study was to test whether lambing season affects maternal and neonatal behaviors in D’man sheep. During four different lambing seasons (winter, autumn, summer and spring), periparturient ewes (n = 111) and their lambs (n = 213) were kept under 24-h-video surveillance in order to record postpartum behaviors. Mother-young preference was tested around 48 h after parturition. Lamb vigor was studied by the determination of birth weight, early postnatal behavior and rectal temperature at birth and 48 h later. Litter expulsion time was not affected by lambing season, but birth weight was biased against summer and winter born lambs. Ewes provided a higher intensity of care to their offspring in winter: latency for grooming was shorter and time spent grooming was longer compared to lambing in spring and summer (P = 0.01 in all cases). On the other hand, lambs were the most active in spring as they were faster to extend their hind legs (P = 0.01), stand up (P = 0.04) and reach the udder (P = 0.04). Rectal temperature at 48 h was affected by season of birth (P < 0.001) with higher values observed in summer. Glycemia variation between birth and 48 h was the lowest in spring born lambs and plasma levels increased less in spring born lambs than in winter (P < 0.0001), autumn (P < 0.0001) and summer born lambs (P < 0.0001). In the choice test, mothers clearly preferred their own young and no season effect was detected except that in the first minute of the test they spent less time near their own young in winter than in the other seasons (P = 0.04). Lambs also chose their mother successfully without any major effect of the season however, but winter born lambs were the least vocal (P = 0.01). Overall, this study show that maternal care, lamb behavior and vigor vary lightly according to seasons, albeit not in a consistent manner. In conclusion, a season is no more detrimental than another for the onset of mother-young relationships.

Bastian, Jetten, and Ferris (2014) reported that shared pain enhances people’s bonding and cooperative behavior, but that shared no-pain has no such effect. They concluded that shared pain is a type of social glue that can improve people’s cooperation. However, in real life, both painful and painless experiences are often nonshared. Logically, the most direct way to determine whether sharing is the important element or not is to compare shared conditions with nonshared conditions. We conducted two experiments to investigate the relative effects of pain and sharing on enhancing people’s bonding and cooperative behavior by adding conditions of unshared pain and unshared no-pain. In experiment 1, we replicated Bastian, Jetten, and Ferris’s (2014) findings, and found that the effect of pain on bonding was mediated by empathy. In experiment 2, we used a 2 (pain/no-pain) × 2 (shared/unshared) design and found that while shared pain still induced more cooperative behavior than shared no-pain, unshared pain did not induce more cooperative behavior than unshared no-pain. Moreover, we found that empathy significantly mediated the relationship between pain and bonding when participants shared the experience. These results suggest that sharing is a necessary component for pain to act as social glue.

Concrete is the most used material in the world after water because of its good mechanical characteristics and its reasonable cost. However, reinforced concrete structures can be damaged by corrosion or other chemical attacks and require repair and maintenance. The repair materials need to satisfy some mechanical and physico-chemical characteristics. Ready-made repair mortars are widely used. However, they are quite expensive, generally imported and they frequently incorporate low volume of synthetic fibers. This paper reports an experimental investigation designing an environmental friendly repair mortar made of local mineral addition (natural pozzolan (PN) and slag (SL)) and local natural fibers. The natural fibers used are Alfa fibers and date palm tree fibers at a volume ratio of 0.75%. The physical and mechanical properties studied are compressive strength, bending strength, total shrinkage and bond strength by slant shear and pull-off tests. The durability of the mortar was assessed by water capillary absorption. The results are compared to those of a reference mortar. The results showed that the substitution of cement by slag and natural pozzolan lead to a decrease in shrinkage (at 28 days of age). The use of date palm and alfa fibers improves the bending strength but reduces compressive strength. According to the results of the pull-off tests, only mortars containing slag meet the minimum value (1.5 MPa) required by EN1504-3. The types of failures observed for most composites show that they can be successfully applied with 20 mm thick layers.

Using water as an example, it is shown that monitoring the change in the loss tangent is a high sensitive method that allows determining the activation energy of relaxation processes in nanostructured water with high accuracy. The use of sensors, the electrodes of which are not in direct contact with the liquid under study is shown to be reasonable. The conditions for obtaining reliable information on the properties of water and its solutions are also justified, namely: measurements should be carried out using pulse methods for several seconds, and then measurements should be stopped to avoid contamination of the solutions studied by electrolysis products. The method of monitoring the magnitude of the loss tangent at fixed frequencies allows the acidity of solutions (pH value) to be controlled at the same time without using specialized instruments for acidity studying.

Ionic hydrogels are an abundant class of materials with applications ranging from drug delivery devices to high performance concrete to baby diapers. A more thorough understanding of interactions between polyelectrolyte networks and ionic solutes is critical as these materials are further tailored for performance applications in highly targeted ionic environments. In this work, we seek to develop structure-property relationships between polyelectrolyte gels and environments containing high concentrations of multivalent ions. Specifically, this work seeks to elucidate the causes behind differences in hydrogel response to divalent ions of main group metals versus transition metals. PANa-co-PAM hydrogels containing low and high fractions of ionic groups are investigated in solutions of DI water, NaCl, CaCl2, and CuSO4 at concentrations ranging from 5 to 100 mM in order to understand 1) the transient or permanent nature of crosslinks produced in these networks by divalent counter-ions, 2) the role of polymer ionic content in these interactions, and 3) how these interactions scale with salt concentration. Gravimetric swelling and mechanical compression testing are employed to characterize water and salt-swollen hydrogels in order to develop guiding principles to control and manipulate material properties through polymer-counter-ion interactions. The work presented here confirms the formation of permanent crosslinks by transition metal ions, offers explanation for the behavioral discrepancy observed between ionic hydrogels and main group versus transition metal ions, and illustrates how such hydrogel properties scale with counter-ion concentration.

Phase-change materials (PCMs) have demonstrated a wide range of potential applications ranging from electronic memories to photonic devices. These applications are enabled by the unconventional portfolio of properties that characterizes crystalline PCMs. Here, we address the origin of these unusual properties and how they are related to the application potential of these materials. Evidence will be presented that the properties are related to an unconventional bonding mechanism. Employing a novel map, which separates solids according to the number of electrons transferred and shared between adjacent atoms, it is shown that PCMs occupy a well-defined region. Depicting physical properties such as the optical dielectric constant as the third dimension in the map reveals systematic property trends. Such trends can be utilized to unravel the origins of the unconventional materials properties or alternatively, as a means to optimize them.

This article overviews the ultrasonic welding process, a solid-state joining method, using the example of welding of a magnesium alloy as well as the joining of magnesium alloys in general. In situ high-speed imaging and infrared thermography were utilized to study interfacial relative motion and heat generation during ultrasonic spot welding of AZ31B magnesium (Mg) alloys. A postweld ultrasonic nondestructive evaluation was performed to study the evolution of local bond formation at the faying interface (contact surface of the joint between the top and bottom Mg sheets) at different stages of the welding process. Two distinct stages were observed as the welding process progresses. In the early stage, localized reciprocating sliding occurred at the contact faying interface between the two Mg sheets, resulting in localized rapid temperature rise from the localized frictional heating. Microscale (submillimeter) bonded regions at the Mg–Mg faying surface started to form, but the overall joint strength was low. The early-stage localized bonds were broken during the subsequent vibrations. In the later stage, no relative motion occurred at any points of the faying interface. Localized bonded regions coalesced into a macroscale joint that was strong enough to prevent the Mg–Mg interface from further breakage and sliding. With increasing welding time, the bonded area continued to increase.

Advanced lightweight materials, including high-strength steels, aluminum, magnesium, plastics, and reinforced polymer composites, are increasingly used in industry. Combinations of mixed materials are becoming commonplace in the design of structures. Adhesives can be used to join a wide range and combinations of materials. However, joining of materials depends on their specific characteristics. The choice of adherend material is one particular and important parameter that influences adhesively bonded joint performance, and its effect should be taken into consideration in the design of adhesive joints. This article overviews experimental and modeling investigations on the influence of adherend properties on the strength of adhesively bonded joints.

The amorphous structures of poly-CO, P-N and N-CO extended solids at high pressures were predicted using density functional theory (DFT) and evolutionary algorithms employing variable and fixed concentrations of components methods. Compression of random network of poly-CO up to 45 GPa results in elimination of small rings of the amorphous network. The amorphous structure with stoichiometry N9P was found to be dynamically stable (no imaginary frequencies in phonon-dispersion curve), stable relative transformation to solid nitrogen and phosphorus, but metastable according to convex hull calculations. The amorphous structure of the N-CO extended solid was obtained with various concentrations of N atoms under isotropic compression up to 50 GPa and release of pressure down to 5 GPa calculated using DFT. The higher concentration of CO is found to be favourable for stabilization of an amorphous covalent N-C-O network consisting of chains and a cage of the network. Upon lowering the pressure and decomposition of the compressed extended solid, atoms are disconnected first from the ends of polymeric chains, while rings of random network are sustained almost intact. Results of a calculated Raman spectra are compared with available experimental results.

Optical isolators and circulators are important elements in many photonic systems. These nonreciprocal devices are typically made of bulk optical components and are difficult to integrate with other elements of photonic integrated circuits. This article discusses the best performance for waveguide isolators and circulators achieved with heterogeneous bonding. By virtue of the bonding technology, the devices can make use of a large magneto-optical effect provided by a high-quality single-crystalline garnet grown in a separate process on a lattice-matched substrate. In a silicon-on-insulator waveguide, the low refractive index of the buried oxide layer contributes to the large penetration of the optical field into a magneto-optical garnet used as an upper-cladding layer. This enhances the magneto-optical phase shift and contributes greatly to reducing the device footprint and the optical loss. Several versions of silicon waveguide optical isolators and circulators, both based on the magneto-optical phase shift, are demonstrated with an optical isolation ratio of ≥30 dB in a wavelength band of 1550 nm. Furthermore, the isolation wavelength can be effectively tuned over several tens of nanometers.