Major Path Research Articles

High Dynamics of Ciliate Community Revealed via Short-Term, High-Frequency Sampling in a Subtropical Estuarine Ecosystem.

Ciliates are pivotal components of the marine microbial food web, exerting profound impacts on oceanic biogeochemical cycling. However, the temporal dynamics of ciliate assemblages on a short time scale in the highly fluctuating estuarine ecosystem remain largely unexplored. We studied changes in the ciliate community during a short time frame in the high salinity waters (>26) of a subtropical estuary. Ciliate abundance, biomass, size and oral diameter structure, and community composition fluctuated considerably and irregularly over a few days or even a few hours. Spearman correlations and the generalized linear model revealed that heterotrophic prokaryotes (HPs) and viral abundances drove the dynamics of ciliate abundance and biomass. The structural equation model further identified a major path from the high-fluorescence content virus (HFV) to HPs and then ciliates. Given the substantial correlation between salinity and HPs/HFV, we proposed that the response of HPs and HFV to salinity drives the dynamics of ciliate biomass. Additionally, the Mantel test showed that phytoplankton pigments such as Lutein and Neoxanthin, phosphate, and pigmented picoeukaryotes were key covariates of the ciliate community composition. This study demonstrated the highly changing patterns of ciliate assemblages and identified potential processes regulating ciliate biomass and community composition on short timescales in a subtropical, hydrographically complex estuary.

Source contributions and drivers of physiological and psychophysical cobenefits from major air pollution control actions in North China

North China is among the most polluted regions in the country, and human exposure to PM2.5 (particulate matter with an aerodynamic diameter less than 2.5 μm) in this region has led to severe health consequences. The region has also benefited the most from emission reductions in recent years. It is of interest to understand to what extent and through which paths emissions from different sectors cause adverse health impacts. Here, we present the results of a full evaluation of the health benefits of emission control actions implemented in recent years based on segregated emission inventories with an emphasis on residential emissions. Two major causal paths, one from residential emissions to indoor air pollution, exposure, and premature deaths, and the other from nonresidential emissions to ambient air pollution and psychophysical impacts, were identified and quantified. From 2014 to 2019, both ambient (33%) and indoor (39%) PM2.5 decreased significantly, leading to decreasing trends in exposure (36%), premature deaths (10%), and psychophysical impacts (21%). The Air Pollution Prevention and Control Action Plan, the Clean Heating Campaign, and spontaneous residential shifts to clean energy contributed significantly to these reductions when the effects of other drivers, such as population and economic growth, were excluded.

Bimolecular reactions on sticky and slippery clusters: Electron-induced reactions of hydrogen peroxide.

Nanoparticles can serve as an efficient reaction environment for bimolecular reactions as the reactants concentrate either inside the nanoparticle or on the surface of the nanoparticle. The reaction rate is then controlled by the rate of formation of the reaction pairs. We demonstrate this concept on the example of electron-induced reactions in hydrogen peroxide. We consider two types of nanoparticle environments: solid argon particles, only weakly interacting with the hydrogen peroxide reactant, and ice particles with a much stronger interaction. The formation of hydrogen peroxide dimers is investigated via classical molecular dynamics (MD) simulations on a microsecond timescale. With a modified force field for hydrogen peroxide, we found out a fast formation and stabilization of the hydrogen peroxide dimer for argon nanoparticles, while the reaction pair was formed reversibly at a much slower rate on the water nanoparticles. We have further investigated the electron-induced reactions using non-adiabatic ab initio MD simulations, identifying the possible reaction products upon the ionization or electron attachment. The major reaction path in all cases corresponded to a proton transfer. The computational findings are supported by mass spectrometry experiments, where large ArM and (H2O)M nanoparticles are generated, and several hydrogen peroxide molecules are embedded on these nanoparticles in a pickup process. Subsequently, the nanoparticles are ionized either positively by 70eV electrons or negatively by electron attachment at electron energies below 5eV. The recorded mass spectra demonstrate the efficient coagulation of H2O2 on ArM, while it is quite limited on (H2O)M.

Multi-path effect in population transfer dynamics of the photoassociation of hot Mg atoms by a femtosecond laser pulse

We investigate the thermal photoassociation dynamics of the Mg atoms, from the X1Σg+ state to the (1)1Πg state, or to the other three higher excited states |i〉=(1)1Πu,(2)1Πu,(2)1Σu+. The weak two-photon coupling between X1Σg+ and (1)1Πg, the strong three-photon couplings between X1Σg+ and |i〉, and the one-photon couplings between (1)1Πg and |i〉 can form several different transition paths. We find that X1Σg+⟶+3ℏω|i〉⟶-ℏω(1)1Πg is the major path and the “V”-type Raman transition path from |i〉 to (1)1Πg takes the second place.

Efficiency and Forward Voltage of Blue and Green Lateral LEDs with V-shaped Defects and Random Alloy Fluctuation in Quantum Wells

For nitride-based blue and green light-emitting diodes (LEDs), the forward voltage $V_\text{for}$ is larger than expected, especially for green LEDs. This is mainly due to the large barriers to vertical carrier transport caused by the total polarization discontinuity at multiple quantum well and quantum barrier interfaces. The natural random alloy fluctuation in QWs has proven to be an important factor reducing $V_\text{for}$. However, this does not suffice in the case of green LEDs because of their larger polarization-induced barrier. V-defects have been proposed as another key factor in reducing $V_\text{for}$ to allow laterally injection into multiple quantum wells (MQWs), thus bypassing the multiple energy barriers incurred by vertical transport. In this paper, to model carrier transport in the whole LED, we consider both random-alloy and V-defect effects. A fully two-dimensional drift-diffusion charge-control solver is used to model both effects. The results indicate that the turn-on voltages for blue and green LEDs are both affected by random alloy fluctuations and V-defect density. For green LEDs, $V_\text{for}$ decreases more due to V-defects, where the smaller polarization barrier at the V-defect sidewall is the major path for lateral carrier injection. Finally, we discuss how V-defect density and size affects the results.

Analysis of oxygen-containing species in coal tar by comprehensive two-dimensional GC×GC-TOF and ESI FT-ICR mass spectrometry through a new subfraction separation method

High oxygen content and ultracomplex composition are the biggest property characteristics of coal tar, which is also the biggest reason for the difficulty of coal tar separation and processing. The distribution of oxygen-containing compounds (OCs) and asphaltene island/archipelago structure play a key role in the solubility and hydrogenation thermal conversion of coal tar. In this study, the composition and structure of OCs in medium and low temperature coal tar (MLCT) and its subfractions were innovatively studied in the molecular level by GC × GC-TOF MS and negative ion ESI FT-ICR MS coupled with collision-induced dissociation (CID) through isolating a narrow mass-defined window based on the improved MLCT subfraction separation method. It revealed that the predominant OCs in MLCT are phenols with relatively few naphthols, furans, and ketones. The OCs are hugely dominated by Ox species in aromatics, resins, and asphaltenes. The polyoxygenated OCs primarily exist in heavier components like asphaltenes. The O atoms prefer to be linked to the outsides of aromatic ring in the form of hydroxyl or carboxyl for low oxygen-containing compounds, and embedded in aromatic rings as the furan rings or cyclic ethers for multiple oxygen-containing compounds. Some Ox species with a high H/C contain relatively smaller aromatic cores with more alkyl sidechains, which are the “atypical” molecules with multiple heteroatoms and low DBE in MLCT asphaltenes. Besides, the island-type structures are dominant for OCs in MLCT. The OxNn compounds have greater island attributes, especially for the molecules with multiple oxygen atoms. The MLCT asphaltenes contain more archipelago structure than that of aromatics and resins. The aromatic cores of OCs are not easy to be destroyed under the optimized voltage although the bridge bond breaking reaction occurs during CID. The heterolysis mode is absolutely the major bond cleavages path for OCs in MLCT. The heterolysis mechanism influences much on the generation of less-heteroatomic fragments, and the homolytic cleavage play a relatively important role during the generation of poly-heteroatomic fragments.

Inquiry practices and types of knowledge, with paths of logical associations between inquiry questions, presented as part of an open inquiry process

ABSTRACT We examined inquiry practices and types of knowledge presented along with paths of logical associations between inquiry questions as part of an open inquiry process. The study analysed high school biology students’ scientific summaries of open inquiry processes. We found three paths of logical associations between inquiry questions – preliminary to major, major to major and major to theoretical. Planning and design inquiry practices were implemented at similar rates in all paths. Analysis and interpretation practices were highest in the preliminary to major path and application inquiry practices were highest in the major to major path. In the preliminary to major path, procedural, logical, and strategic knowledge was used. Logical and situational knowledge were used in the major to major path, and situational knowledge was used in the major to theoretical path. Our results demonstrated that various inquiry practices and types of knowledge are used at different paths of formulating inquiry questions, specifically those that involve several stages of hands-on activity. Thus, we recommend that high school students should engage in different paths of scientific inquiry processes, specifically those that require them to engage in continuous planning and performing hands-on inquiry activity, to advance inquiry practices and their knowledge base.

Separate and integral effect tests of aerosol retention in steam generator during tube rupture accident

A steam generator tube rupture accompanying a core damage may cause the fission product to be released to environment bypassing the containment. In such an accident, the steam generator is the major path of the radioactive aerosol release.AEOLUS facility, the scaled-down model of Korean type steam generator, was built to examine the aerosol removal in the steam generator during the steam generator tube rupture accident. Integral and separate effect tests were performed with the facility for the dry and flooded conditions, and the decontamination factors were presented for different tube configurations and submergences.The dry test results were compared with the existing test results and with the analyses to investigate the aerosol retention physics by the tube bundle, with respect to the particle size and the bundle geometry. In the flooded tests, the effect of submergence were shown and the retention in the jet injection region were presented with respect to the Stokes number.The test results are planned to be used to constitute the aerosol retention model, specifically applicable for the analysis of the steam generator tube rupture accident in Korean nuclear power plants to evaluate realistic fission product behavior.

Delineation of Near Surface Water Flow Path of Wahawa Geothermal Field by Using 2D Inversion of Resistivity Data

The Wahawa geothermal field which is located in the Eastern province of Sri Lanka has an average temperature of 60°C in its surface manifestations. Since the temperature is considerably high, it is important to explore the feasibility of direct utilization of the energy of this geothermal field. In the present study, electrical resistivity measurements were employed in a 20 km2 region in order to delineate the Wahawa geothermal system and to understand the near-surface fracture pattern. Electrical resistivity mapping of the region has been carried out using Schlumberger array measurements with nominal current array spacing (half spacing) of 150 m and it was observed that there was a path of low ( W) apparent resistivity. These results revealed that the hotsprings resting on a hard rock terrain are presumably composed of metamorphic rocks, suggesting lateral movement of hotwater towards the hotsprings instead of a deep-influx. The area of surface manifestations is not suitable for utilization application due to clustering of the main feeding path. The major hotwater feeding path which is extending in the west direction can be recommended as a possible drilling target for direct utilization applications.

Lumped geohydrological modelling for long-term predictions of groundwater storage and depletion

Excessive groundwater pumping exacerbates aquifer depletion and poses a major threat in regions all around the world that already suffer from overuse or climate change. In this situation, accurate and reliable predictions of long-term aquifer water balances are key prerequisites to manage groundwater sustainably. Compared to spatially explicit numerical models, lumped hydrological models are computationally fast, lean on data requirement and more accessable for quantifying uncertainty. However, lumped hydrological models are mainly designed to simulate river discharge only, not aquifer storage. Consequently, calibration only includes stream flow data. In this study, we hypothesize that we can extend a lumped hydrological models (here HBV) towards a lumped geohydrological model (LGhM) by additional, designated terms for water budget and groundwater storage. The model building is inspired by the geometry and hydrogeological large-scale properties of the catchment’s aquifers. Underground flow routing resembles major groundwater flow paths. The model is calibrated and evaluated on both groundwater storage data and surface discharge data. We apply our LGhM to a MODFLOW-based virtual reality describing the unconfined Wairau Plain Aquifer, New Zealand. We consider and discuss specifically river-groundwater exchange processes, long-term forecast of aquifer storage dynamics, and groundwater depletion in a hypothetical, persistent drought. Our model evaluation shows very plausible predictive capabilities in 40-year forecasts with synthetic weather time series and several years of groundwater depletion in the extreme drought case.

Diffuse scattering model for human brain wave (Alpha) propagation prediction during meditation inside a temple, through ray tracing, a hypothetical study

Electromagnetic radio waves have been propagating for billions of years through the universe since the beginning of time. Electromagnetic radio wave propagation and the communication revolution it spawned, however are products of the twentieth century. Radio propagation in a particular environment is a complex, multipath phenomenon which involves several different mechanisms. According to a traditional, simplified approach, two major urban propagation mechanisms are identified over-roof-top (ORT) or vertical propagation (VP), where one major radial path undergoes multiple diffractions on building tops, and lateral propagation (LP) where several rays reflect/diffract all vertical building walls/edges according to the geometrical Optics (GO) rules before reaching the receiver.

Boosting principles for the photocatalytic performance of Cr-doped Cu2O crystallites and mechanisms of photocatalytic oxidation for levofloxacin

Cr-doped Cu2O crystallites were synthesized by hydrothermal process. XRD, BET, SEM, TEM, UV–Vis and RSM were used to reveal the microstructure, optical characteristics and photocatalytic activity of the Cr-doped Cu2O crystallites. The main degradation intermediates and degradation reaction pathways of levofloxacin were distinguished based on HPLC-MS/MS. The potential photocatalytic reaction points of levofloxacin and the degradation intermediates were analysed using frontier electron densities. The results indicated that the synthesized Cr-doped Cu2O crystallites had higher specific surface and visible light absorptance than the pure Cu2O crystallites. The doping of Cr introduced impurity levels in the lattice of Cu2O and increased the forbidden band width of Cu2O crystallites, causing a blueshift of the absorption boundary. The prepared crystallites had high purity, and the morphologies of the prepared Cu2O, K1-Cu2O, K2-Cu2O and K3-Cu2O crystallites were spheres, polyhedrons, octahedrons and cubes, respectively. The main active factors of the photocatalytic reaction for levofloxacin were photogenerated holes and hydroxyl radicals. The K2-Cu2O sample had the strongest photocatalytic degradation efficiency and reusability for levofloxacin. The degradation rates of levofloxacin after the first and 8 cycling experiments reached 79.6% and 72.4%, respectively. Ten main intermediates in the degradation of levofloxacin were determined. The ring opening and decarboxylation of piperazine and quinolones might be the major paths of photocatalytic reactions. This research thoroughly revealed the mechanisms of photocatalytic reactions and performance improvements in Cr-doped Cu2O crystallites.

Effect of Bonding Strength on Electromigration Failure in Cu-Cu Bumps.

In microelectronic packaging technology for three-dimensional integrated circuits (3D ICs), Cu-to-Cu direct bonding appears to be the solution to solve the problems of Joule heating and electromigration (EM) in solder microbumps under 10 in diameter. However, EM will occur in Cu–Cu bumps when the current density is over . The surface, grain boundary, and the interface between the Cu and TiW adhesion layer are the three major diffusion paths in EM tests, and which one may lead to early failure is of interest. This study showed that bonding strength affects the outcome. First, if the bonding strength is not strong enough to sustain the thermal mismatch of materials during EM tests, the bonding interface will fracture and lead to an open circuit of early failure. Second, if the bonding strength can sustain the bonding structure, voids will form at the passivation contact area between the Cu–Cu bump and redistribution layer (RDL) due to current crowding. When the void grows along the passivation interface and separates the Cu–Cu bump and RDL, an open circuit can occur, especially when the current density and temperature are severe. Third, under excellent bonding, when the voids at the contact area between the Cu–Cu bump and RDL do not merge together, the EM lifetime can be more than 5000 h.

A Bifunctional Lead–Iron Oxyfluoride, PbFeO2F, That Drives Photoelectrochemical and Electrochemical Water Oxidation

Introduction Photoelectrochemical water splitting has attracted attention as a method of generating solar fuel, such as hydrogen that is expected to be utilize as a renewable energy carrier and clean fuel of an internal‐combustion engine.1 In the photoanode materials reported so far, ordinary metal oxides require ultraviolet light for operation because of their wide bandgaps (>3 eV), and visible-light-responsive metal oxides need an additional electrochemical bias because their conduction-band minimum is a lower position than the H+/H2 reduction potential. Mixed-anion compounds fascinating recent photocatalyst researchers possess visible-light response because of a narrow bandgap with less electronegative anion species.1,2 However, they are not very stable for water oxidation, because photogenerated holes oxidize the anion species except for oxygen in the compounds. Recently, we have reported an oxyfluoride Pb2Ti2O5.4F1.2 as a stable photoanode material that absorbs visible light at wavelengths as long as ~500 nm.3 The VBM of Pb2Ti2O5.4F1.2 is mainly composed by the O 2p orbitals. As the result, the Pb2Ti2O5.4F1.2 photoanode is essentially stable toward self-oxidation by photogenerated holes. However, this is the sole example of a visible-light-responsive oxyfluoride photoanode. Development of a new oxyfluoride photoanode absorbing visible light is important for enabling the further design of visible-light-responsive photoanode materials. In the present work, a lead–iron oxyfluoride PbFeO2F is applied to a photoanode material and electrocatalyst for water-oxidation. PbFeO2F, which can be synthesized by a high-pressure method,4 has been reported to show a yellow colour. Thus, it is expected to function as a visible-light-responsive photoanode material. Moreover, PbFeO2F containing Fe cation is possible to provide catalytic performance for water oxidation, which means that this material may also function as an electrocatalyst. Results and Discussion According to the previously reported method,4 PbFeO2F powder was synthesized. It was deposited on a fluorine-doped tin oxide (FTO) glass substrate by electrophoresis. The PbFeO2F/FTO electrode was subjected to post-necking treatment by immersing in 0.1 M Ti{OCH(CH3)2}4 –isopropanol solution to deposit TiO2 layer (TiO2/PbFeO2F/FTO electrode), followed by electrodeposition of cobalt phosphate (Co-Pi) cocatalyst (Co-Pi/TiO2/PbFeO2F/FTO electrode). Linear-sweep voltammetry of the as-prepared electrodes in 0.1 M K3PO4 solution was conducted under intermittent visible-light irradiation (Figure 1A). The PbFeO2F/FTO electrode exhibited no photocurrent response. By contrast, a slight photocurrent response was observed for the TiO2/PbFeO2F/FTO electrode because of mainly improved interparticle conductivity in the electrode. Furthermore, a clear anodic photocurrent was observed for the Co-Pi/TiO2/PbFeO2F/FTO electrode. Loading the Co-Pi cocatalyst, known as a water-oxidation promoter, improved charge transfer at the electrode/water interface and charge separation from the surface to the bulk. Besides, the Co-Pi/TiO2/PbFeO2F/FTO electrode exhibited an anodic photocurrent under visible-light irradiation with wavelengths as long as ~600 nm. It indicates that PbFeO2F can function as a photoanode material under a wide range of visible-light wavelengths. Controlled-potential electrolysis with the as-prepared PbFeO2F/FTO electrode was operated at +1.7 V vs. RHE under dark conditions (Figure 1B). The evolved O2 was observed by GC analysis in the measurement. It was almost one-fourth the amount of electrons, which flowed during the electrolysis, giving a high Faradaic efficiency of 97%. This result means that the water oxidation was the major path at the PbFeO2F/FTO electrode. In addition, α-Fe2O3/FTO electrode does not work at this potential because of the larger overpotential than the PbFeO2F/FTO electrode for water oxidation. It reveals that PbFeO2F can also function as an electrocatalyst at a relatively low overpotential for water oxidation. References Seo, H. Nishiyama, T. Yamada and K. Domen, Visible-Light-Responsive Photoanodes for Highly Active, Stable Water Oxidation, Angew. Chem. Int. Ed., 57, 8396 (2018).Miyoshi and K. Maeda, Recent Progress in Mixed‐Anion Materials for Solar Fuel Production, Solar RRL, in press.Hirayama, H. Nakata, H. Wakayama, S. Nishioka, T. Kanazawa, R. Kamata, Y. Ebato, K. Kato, H. Kumagai, A. Yamakata, K. Oka and K. Maeda, Solar-Driven Photoelectrochemical Water Oxidation over an n-Type Lead-Titanium Oxyfluoride Anode, J. Am. Chem. Soc., 141, 17158 (2019).Inaguma, J.-M. Greneche, M.-P. Crosnier-Lopez, T. Katsumata, Y. Calage and J.-L. Fourquet, Structure and Mössbauer Studies of F−O Ordering in Antiferromagnetic Perovskite PbFeO2F, Chem. Mater., 17, 1386 (2005). Figure 1

Servitization and Sustainable Value Creation Strategy for China’s Manufacturing Industry: A Multiple Case Study in the Belt and Road Initiative

Manufacturers are adding service offerings to satisfy customers’ needs in various markets. Effective strategies for servitization can improve the competitiveness of manufacturers during cooperation. The Belt and Road Initiative (BRI) established by China offers opportunities for economic cooperation and regional integration for the involved countries. Now, many manufacturing firms are expanding their businesses into Belt and Road countries, most firms are facing the “how to do” problems in improving sustainability during their cooperation. They urgently require methodical assistance on both improving competitiveness through servitization and addressing sustainability challenges. This necessitates the firms to develop successful service models for their industrial initiatives and investigate ways to produce long-term sustainable value through services. In addition to the firm’s economic worth, it also entails lowering the project’s negative environmental impact. The results provided effective strategies for manufacturers from two perspectives. The first perspective is the study discovered innovative service models at both the product and project levels. Project-service systems are critical, and manufacturing firms should use innovative service models to deliver projects. The operation method of holistic solution and localization integration project service was addressed in particular in this study. In the second perspective, there are suggestions for achieving sustainability through innovative service models. The methods for preserving sustainable value on the industrial project level were the subject of our study, which included significant criteria and detailed descriptions. The effective project service system should bring sustainable value to the lifespan of an industrial project. This study has determined four major paths to improving sustainable value creation through servitization: improving resource allocation capabilities, reduce carbon emissions through energy project service, technological outputs, and standards exportation. Useful recommendations are provided for manufacturing firms planning to develop their business overseas, especially in BRI countries.

Exploring Negative Spillover Effects on Stakeholders: A Case Study on Social Media Talk about Crisis in the Food Industry Using Data Mining

Focusing on public-centered, social-mediated crisis communication, the current exploratory study drew on situational crisis communication theory to formulate a comprehensive view of consumer reactions to crisis. Data mining and automated content analysis techniques were utilized to analyze social media posts by the public during a crisis in the cereals industry. Two path analyses showed that: (a) crisis-related social media posts tended to skip over competitor brand products, followed by two major reaction paths—(1) a rational path based on guilt attribution that justifies implications for the company and (2) an emotional path associated with public distrust; and (b) public self-blame spilled over to other stakeholders such as the government and economic system. The results give voice to issues that concern the public during crises, both as individuals and as a community. They highlight the fact that sustainable crisis management should involve additional stakeholders. Conclusions and implications for society and practice are suggested.

Experimental and kinetic modeling studies of polyoxymethylene dimethyl ether (PODE) pyrolysis in jet stirred reactor

Polyoxymethylene dimethyl ethers (DMMn) is regarded as a potential alternative fuel for transportation utilization. The jet stirred reactor (JSR) pyrolysis of DMM1−3 was studied at temperatures of 450∼1080 K and pressures of 1.03 atm with the residence time (τ) of 2 s. A gas chromatography/mass spectrometry (GC–MS/FID) was used to detect and provide reliable pyrolysis experimental data. Seven key pyrolysis products were detected and measured in the present work, including fuel, methyl formate, methanol, acetaldehyde, methane, ethane and ethylene. A detailed kinetic model of DMM1−3 pyrolysis was elaborated. Both rate of production (ROP) and sensitivity analysis were performed to reveal the DMM1−3 pyrolysis processes. Results show that the chemical kinetic simulation can reproduce the consumption of fuel and most intermediate species reasonably well. With the increase of n from 1 to 3 inside DMM1−3, the reactivity increases evidently and the initial pyrolysis temperature decreases significantly, which is mainly resulted from different fuel-specific chain initiation reactions of DMM1−3. Methane and methyl formate are two detected key species with relatively significant concentrations. It was revealed that the fuel-specific chain initiation reactions of DMM1−3 can also significantly affect the production and consumption paths of methyl formate. In addition to the major production and consumption paths of formaldehyde, two key competitive channels were found to perform relatively high negative sensitivity to formaldehyde production of DMM2 and DMM3.

Vibration transmission and energy flow analysis of L-shaped laminated composite structure based on a substructure method

This study investigates the vibration power flow characteristics of a harmonically excited L-shaped laminated composite structure with flat sub-plates connected at a right angle. A substructure-based power flow analysis (SPFA) method is developed based on analytical, numerical, and hybrid approaches of determining the receptance functions of sub-plates and by using the force balance and geometrical compatibility conditions at the coupling edge. The SPFA methods are then used to evaluate the vibration energy input into the structure and energy transmission through the coupling edge. The power flow density vector is defined, and its time-averaged value is used to clearly illustrate the energy sources and sinks as well as the energy transmission paths within the sub-plates. The influence of different combinations of fibre orientations for the sub-plates and the excited dominant global modes of the joined structure on the major vibration energy transfer paths are investigated. It is found that the fibre orientation can have significant effects on transmission paths and potential positions of sinks. From the vibration energy flow perspective, the fibre angles of the integrated laminated composite structure can be tailored for desirable energy transmission paths.

Contesting digital leisure time: Parental struggles in relation to young children's play with tablets at home

AbstractYoung children's practices with tablet computers has been a topic in parenting discourses for several years, drawing on earlier debates over technologies and media in children's lives. In this article, I analyse data from a video observation–based media ethnography of seven Danish children (aged 4–6) and engage with the research tradition attributed to parental mediation. The analysis suggests two major paths in the struggles that stand out from the discourses and in situ practices of parents and children in the empirical data. These paths encompass struggles in relation to supporting and directing children's play activities and setting boundaries in their use of tablets and content. The nuances and implications of both paths are analysed and discussed in terms of strategies that emerge to support children's agency and rapport with parents, as well as what this means for future research.

Nickel-Catalyzed Annulations of ortho-Haloarylimines.

We report the discovery, development, and mechanism of a nickel-catalyzed annulation reaction between o-haloarylimines and electron-poor olefins. The reaction produces two adjacent anti stereocenters and a free secondary amine. Spirocycles are formed from cyclic imines. We characterized the key oxidative addition intermediate and identified a major path leading to competing homocoupling products. The activation energy of oxidative addition and the rate of oxidative addition complex isomerization were determined. The sensitivity of the reaction to reaction conditions was established in a quantitative manner and both the scope and limitations of the method are presented.