Positive Energy Research Articles

Sodium Halide-Based Solid Electrolyte with High Ionic Conductivity

Sodium-ion batteries (SIBs) are considered one of the most prominent alternatives to lithium-ion batteries (LIBs) because of the abundance of sodium resources on Earth. However, compared to Li, Na has a heavier atomic weight (23 g mol–1 vs. 6.9 g mol–1) and higher standard potential, leading to lower volumetric and gravimetric energy density of SIBs than LIBs. The energy density of state-of-the-art room-temperature SIBs is in the range of 75 – 165 W h kg–1 or 250 – 375 W h L–1. To increase the energy density of SIBs, Na metal is proposed to be used as the anode material due to its superior theoretical specific capacity (1166 mA h g–1). To tackle the safety challenges brought by using Na metal, applying solid electrolytes (SEs) has been proposed to be an effective strategy. Despite the tremendous progress that has been made in the past decades, the progress and application are still in the infancy, experiencing numerous challenges for sodium solid-state batteries due to inherently low room-temperature ionic conductivity, interface complications, and fabrication.Inorganic halide-based SEs have emerged as a game changer because of their fast-conducting characteristics, adequate thermodynamic stability, great deformability, and good oxidative stability.1 Moreover, halide-based SEs are generally stable against moisture owing to their positive hydrolysis reaction energy. However, most of the studied halide-based SEs are based on the Li-ion system, with only a few based on the Na-ion system. Moreover, despite halide-based Na SEs theoretically having high ionic conductivity,2 experimental obtained samples have much lower ionic conductivities compared to their Li counterparts (usually < 0.1 mS cm–1). Therefore, developing halide-based SEs with high Na+ ionic conductivity is crucial for Na ASSBs. We recently identified a new Na halide-based SE with a room temperature Na+ ionic conductivity over 1 mS cm–1. The activation energy is also as low as 0.23 eV. Interestingly, the material shows a mixed amorphous and crystalline phase, and its ionic conductivity decreases with the increase of the crystalline phase. The ionic conductivity of > 1 mS cm–1 is already comparable to some organic liquid electrolytes and thus is sufficient for many practical applications. The developed strategy has the potential to be applied to other halide-based SEs to improve their ionic conductivity, promoting the development of SIBs.(1) Huang, J.; Wu, K.; Xu, G.; Wu, M.; Dou, S.; Wu, C. Recent Progress and Strategic Perspectives of Inorganic Solid Electrolytes: Fundamentals, Modifications, and Applications in Sodium Metal Batteries. Chem. Soc. Rev. 2023, 52 (15), 4933–4995.(2) Qie, Y.; Wang, S.; Fu, S.; Xie, H.; Sun, Q.; Jena, P. Yttrium–Sodium Halides as Promising Solid-State Electrolytes with High Ionic Conductivity and Stability for Na-Ion Batteries. J. Phys. Chem. Lett. 2020, 11 (9), 3376–3383.

(Invited) Delayed Fluorescence from Inverted Singlet and Triplet Excited States

Hund’s multiplicity rule states that for a given electronic configuration, a higher spin state has a lower energy. Rephrasing this rule for molecular excited states predicts a positive energy gap between singlet and triplet excited states (∆E ST). Although there is general agreement that ∆E ST must be positive, the potential for negative ∆E ST in phenalene analogues, such as cycl[3.3.3]azine and heptazine has been discussed during the last two decades.1–4 In this presentation, we report a fluorescent heptazine analogue HzTFEX2 that disobeys Hund’s rule, possessing negative ∆E ST of –11 meV (Fig. 1).5 The energy inversion of the singlet and triplet excited states results in delayed fluorescence with short time constants of 0.2 μs, which anomalously decrease with decreasing temperature due to the emissive singlet character of the lowest-energy excited state. Organic light-emitting diodes using this molecule exhibit a fast transient electroluminescence decay with a maximum external quantum efficiency of 17%, demonstrating potential implications for optoelectronic devices.(1) W. Leupin, J. Wirz, J. Am. Chem. Soc. 102, 6068–6075 (1980).(2) W. Leupin, D. Magde, G. Persy, J. Wirz, J. Am. Chem. Soc. 108, 17–22 (1986).(3) J. Ehrmaier, E. J. Rabe, S. R. Pristash, K. L. Corp, C. W. Schlenker, A. L. Sobolewski, W. Domcke, J. Phys. Chem. A 123, 8099–8108 (2019).(4) P. de Silva, J. Phys. Chem. Lett. 10, 5674–5679 (2019).(5) N. Aizawa, Y.-J. Pu, Y. Harabuchi, A. Nihonyanagi, R. Ibuka, H. Inuzuka, B. Dhara, Y. Koyama, K. Nakayama, S. Maeda, F. Araoka, D. Miyajima, Nature 609, 502 (2022). Figure 1

Two Finite Element Approaches for the Porous Medium Equation That Are Positivity Preserving and Energy Stable

In this work, we present the construction of two distinct finite element approaches to solve the porous medium equation (PME). In the first approach, we transform the PME to a log-density variable formulation and construct a continuous Galerkin method. In the second approach, we introduce additional potential and velocity variables to rewrite the PME into a system of equations, for which we construct a mixed finite element method. Both approaches are first-order accurate, mass conserving, and proved to be unconditionally energy stable for their respective energies. The mixed approach is shown to preserve positivity under a CFL condition, while a much stronger property of unconditional bound preservation is proved for the log-density approach. A novel feature of our schemes is that they can handle compactly supported initial data without the need for any perturbation techniques. Furthermore, the log-density method can handle unstructured grids in any number of dimensions, while the mixed method can handle unstructured grids in two dimensions. We present results from several numerical experiments to demonstrate these properties.

A High Capacity Gas Diffusion Electrode for Li-O2 Batteries.

The very high theoretical specific energy of the lithium-air (Li-O2) battery (3500Wh kg-1) compared with other batteries makes it potentially attractive, especially for the electrification of flight. While progress has been made in realizing the Li-air battery, several challenges remain. One such challenge is achieving a high capacity to store charge at the positive electrode at practical current densities, without which Li-air batteries will not outperform lithium-ion. The capacity is limited by the mass transport of O2 throughout the porous carbon positive electrode. Here it is shown that by replacing the binder in the electrode by a polymer with the intrinsic ability to transport O2, it is possible to reach capacities as high as 31 mAh cm-2 at 1mA cm-2 in a 300µm thick electrode. This corresponds to a positive electrode energy density of 2650Wh L-1 and specific energy of 1716Wh kg-1, exceeding significantly Li-ion batteries and previously reported Li-O2 cells. Due to the enhanced oxygen diffusion imparted by the gas diffusion polymer, Li2O2 (the product of O2 reduction on discharge) fills a greater volume fraction of the electrode and is more homogeneously distributed.

Rebuilding Ukraine’s energy supply in a secure, economic, and decarbonised way

Abstract Since Russia’s 2022 invasion, Ukraine’s civilian energy infrastructure has faced systematic attack and requires urgent and strategic reconstruction. This study confronts the dual challenges of rebuilding Ukraine’s energy system rapidly to mitigate civilian and economic disruption while aligning this to long-term goals of sustainability and energy security. We demonstrate that Ukraine can readily meet future energy demands through a fully renewable electrified system at costs comparable to those from fossil fuels and nuclear power. Contrary to previous re- liance on high-carbon energy sources, we find a diversified renewable energy portfolio, including significant solar photovoltaic and wind contributions, can ef- ficiently meet growing energy demands and position Ukraine as an energy ex- porter, leveraging its geographical advantages. The approach of our study, based on open data and models, extends beyond national borders and offers a model for post-conflict reconstruction that harmonizes immediate recovery with sustain- able energy transition.

Investigation of the impacts of several diols on the phase behavior and physico-chemical quantities associated with the Triton X-100 and antidiabetic drug mixture

Drug-surfactant interaction phenomena have received popularity in the pharmaceutical industry and technological sectors from the view point of wider applications. Herein, we aimed to investigate the clouding behavior and various thermodynamic properties of Triton X-100 (TX-100) and metformin hydrochloride drug (MNH; an antidiabetic drug) mixture in the attendance of diols followed by the cloud point measurement technique. The dosage form of metformin hydrochloride drug controls the glucose level in the blood. The different types of diols, i.e., ethylene glycol (EG), 1,2-propylene glycol (1,2-PrG), 2,3-butanediol (2,3-BD), and 1,5-pentanediol (1,5-PD) were uniformly used in this inspection. The effect of diols, with the variation of their concentrations on the clouding behavior of TX-100 + MNH mixture having fixed content of TX-100 (92.7 mmol kg−1) and MNH drug (2 mmol kg−1), were examined. The most enhanced CP value was experienced in the aqueous 1,5-PD medium, whereas the lowest CP value was observed in the aqueous EG medium. The CP values were recorded for the working system under the effect of changing concentrations of diols, which were observed to follow the sequential order: CPH2O+1,5−PD>CPH2O+2,3−BD>CPH2O+1,2−PrG>CPH2O+EG. The clouding progression of the working system was realized to be nonspontaneous as concluded from the positive free energy change (ΔGco) values. The positive and negative values of enthalpy (ΔHco) and entropy (ΔSco) change were documented, respectively, at the low and high concentrations of diols. The hydrophobic interactions amongst different components are predominant at the low concentrations of diols, whereas the electrostatic interactions are leading factors at the high concentrations of diols. Enthalpy-entropy compensation parameters were computed and interpreted with proper perceptive. The outcomes of this observation may be effective and helpful in the various industrial sectors, especially in the drug carrier system in the pharmaceutical arena.

Assessment of Zitterbewegung Interpretation for Free Particle Solution Using the Concept of Relativistic Wave

The Assessment of the interpretation of Zitterbewegung for free particle solution using various models has been carried out in this work where we firstly considered by using the free particle solution for which Dirac equation and projection operator were carried out.. ln this case, it was invariably revealed that the solution have two doubly degenerate eigenvalues representing positive and negative state that was further support by the analysis which was carried out using Heisenberg’s equation and the representation in relativistic velocity and semi-classical equation of motion for acceleration., but in this second case, the results obtained were observed to have two terms, first terms standing in for rapidly oscillatory motion and the second term representing average motion of the particle in x-direction. The first term in the expression is the one deemed to signify zitterbewegung which is one considered to be sas a result of the fluctuation resulting from the interference between negative and positive energy state while the other term is the normal state terms signifying the average motion of the particle. This therefore confirms the explicit nature of using Dirac equation in handling problems involving the behavior of free particles in field as compared to the use of semiclassical equation of motion.

Deep retrofitting toward net zero energy building in the Mediterranean region: A case study of Albania

Like many other Mediterranean countries, Albania faces unique challenges and opportunities to achieve an efficient and fully decarbonized household sector by applying real energy efficiency measures and numbers toward nearly zero-energy buildings. The study findings showed that nZEB in 2030 can be achieved by combining active and passive energy efficiency measures. Behind the study's state-of-the-art stands a multivariable regression analysis of both electricity consumption and electricity generation executed for three validated consecutive years, 2021, 2022, and 2023, including demand side (electricity bills) and supply side generation provided from a nearby existing onsite PV with an installed capacity of 5.5 kWp. A good mathematical correlation is carried out using Durbin – Watson criteria on statistics using RETScreen software to correlate electricity consumption and generation as a function of weather parameters for the tested household and selected region. The goals to meet the nZEB concept require the insulation of the existing exterior wall and window replacements in compliance with the Energy Performance Methodology on Building and installing rooftop Solar Water Heating (SWH) panels of 3.73 m2 as expostulated in scenario 7. The simulation results show that integrating a rooftop PV system with an installed capacity of 5.5 kWp would provide enough electricity to convert residential buildings into Positive Energy Buildings in 2050 based on the selected dwelling and location (Mediterranean region). At the national level, the proposed model would reduce the national annual electricity import level by 1.64 %, saving annually around €31,021,162 and reducing at least 0.068 MtCO2 per year. Subsidizing passive energy efficiency measures at a rate of 3 % per year coupled with onsite renewable energy sources schemes and other incentivization pathways from the government and other interested parties at a rate of 80 % in the roadmap towards nZEB and PEB is mandatory.

Biofouling control of thermophilic bacteria in membrane distillation

Previously, fouling of MD membranes was perceived to be minimal due to the operational conditions preventing bacterial growth. However, recent studies presented fouling of MD membranes, largely due to various halophilic and thermophilic bacterial. The current study presented potential of antibacterial cellulose nanocrystals (CNCs) capped silver nanoparticles (AgNPs) towards biofouling control in MD water desalination processes. Interestingly, the CNCs were used as capping and reducing agent in a microwave mediated synthesis of AgNPs. The green synthesis approach of AgNPs and its successful use in MD processes was reported for the first. The MD experiments were carried out using a series of modified PVDF membranes and feed solution spiked with a thermophilic G. stearothermophilus. Upon evaluation of fouled membranes, particularly PVDF, PVP-equipped PVDF, and f-CNTs-modified PVDF, the surface energy of interactions were −131 mJ/m2, −31.5 mJ/m2, −28.6 mJ/m2, suggesting favorable interaction between the membranes and bacterial foulant. The findings of this study were supported by fouling layer and bacterial growth as seen from scanning electron microscopy, atomic force microscopy and Fourier transform infrared results. Upon membrane surface modification using CNCs-capped AgNPs, bacterial growth on membrane surface was reduced. Specifically, the positive cohesion energy between the CNCs-capped AgNPs-modified PVDF membrane and thermophilic bacterial foulant was + 63.2 mJ/m2, distinctly proving reduced fouling. The findings were supported by 5.5 % flux decay of the modified membrane compared to 79.3 % flux decay of virgin PVDF membrane. This suggested a long-term membrane integrity in thermophilic bacterial contaminated feed solutions during the MD water desalination.

Reversible SOCs als Bindeglied zwischen Strom-, Wärme- und Gasnetz und Plus Energie-Quartieren

ZusammenfassungZur Reduktion der CO2-Emissionen im Gebäudeenergiesektor sind alternative Energieerzeugungs- und Energiespeicherkonzepte notwendig. Technologien, die quartiersbezogen zentral sommerliche Überschussenergie aus Erneuerbaren Energien speichern und in weniger ertragreichen Monaten wieder in Strom und Wärme zurückwandeln, sind als Eigenschaften beispielsweise den Elektrolyse- bzw. Brennstoff-Zellensystemen zuzuordnen. Im Projekt Cell4Life wird ein solches System, bestehend aus einer reversibel arbeitenden Festoxidzelle (rSOC) theoretisch und im Labormaßstab im Kontext eines Plus Energie-Quartiers (PEQ) auf dessen funktionale Integrität hin untersucht. Ein Projektziel ist dabei die Optimierung der dynamischen Betriebsweise, für die es zum einen statischer Optimierungsversuche am Prüfstand und zum anderen Gesamtsystemsimulationen bedarf. In dieser Veröffentlichung wird vorgestellt, welche Betriebsweisen statisch optimiert und welche Systemkonzepte innerhalb einer Simulation untersucht werden. Für ein städtisches PEQ hat sich ein rSOC-System, das die Dampfelektrolyse im SOEC-Modus nutzt und im SOFC-Modus mit Wasserstoff und Methan betrieben wird, als am sinnvollsten erwiesen. Darüber hinaus werden reale Betriebsweisen aufbauend auf Wasserstoffbeimischungen in das örtliche Gasnetz in experimentellen Versuchen betrachtet. Basierend auf theoretischen Bedarfsdaten aus dem „PEQ21“ in Wien werden drei Optimierungsszenarien definiert, die neben dem Langzeit- auch den Kurzzeitbetrieb der rSOC-Anlage betrachten.

Advanced Simulation and Analysis of Anisotropic Warp Fields with Positive Energy

This paper presents a comprehensive theoretical model for a warp bubble that enables faster-than-light travel using positive energy densities, an advancement over traditional models that rely on exotic negative energies. Building on the framework proposed by Eric Lentz, we introduce a non-uniform energy distribution model to enhance control and efficiency in warp field generation. The research validates the stability and feasibility of a warp bubble sustained by positive energy through detailed numerical simulations and analysis. Key findings include the discovery of anisotropic behavior in the warp bubble's structure, which allows for directional tuning of the warp field, thereby optimizing space- time manipulation and reducing energy demands. These results represent a significant step forward in the theoretical foundations of warp drive technology and its potential practical applications.

Mapping the Sustainability of Waste-to-Energy Processes for Food Loss and Waste in Mexico—Part 1: Energy Feasibility Study

Mexico generated 8.9 Mt of food loss and waste (FLW) at food distribution and retail centers in the year 2022. Traditional management methods in Latin America primarily involve final disposal sites, contributing to national greenhouse gas emissions of 0.22 Mt CO2 eq y−1. This creates an urgent need for sustainable valorization strategies for FLW to mitigate environmental impacts. This comprehensive study analyzes the geographical distribution of FLW generation and proposes a valorization approach using WtE-AD plants. Geographic information systems were employed for geographical analysis, life cycle assessment was used for environmental evaluation, and circular economy business models were applied for sustainability assessment. The primary objective of this first part of the contribution is to evaluate the technical feasibility of implementing waste-to-energy anaerobic digestion (WtE-AD) plants for FLW management in Mexico considering their geographical locations. The results demonstrate that WtE-AD plants with treatment capacities exceeding 8 t d−1 can achieve positive energy balances and significantly reduce greenhouse gas emissions. Specific findings indicate that these plants are viable for large-scale implementation, with larger plants showing resilience to increased transport distances while maintaining energy efficiency. The results highlight the critical influence of methane yields and transport distances on plant energy performance. This study underscores the importance of strategically placing and scaling WtE-AD plants to optimize resource efficiency and environmental sustainability. These findings provide essential insights for policymakers and stakeholders advocating for the transition of Mexico’s food supply chain toward a circular economy. Future parts of this study will explore detailed economic analyses and the policy frameworks necessary for the large-scale implementation of WtE-AD plants in Mexico. Further research should continue to develop innovative strategies to enhance the techno-economic and environmental performance of WtE-AD processes, ensuring sustainable FLW management and energy recovery.

Energy Management System for a Residential Positive Energy District Based on Fuzzy Logic Approach (RESTORATIVE)

There is a clear European Strategy to transition by 2050 from a fossil fuel-based economy to a completely new system based on renewable energy resources, with electricity as the main energy carrier. Positive Energy Districts (PEDs) are urban areas that produce at least as much energy as their yearly consumption. To meet this objective, they must incorporate distributed generation based on renewable systems within their boundaries. This article considers the fluctuations in electricity prices and local renewable availability and develops a PED model with a centralised energy storage system focused on electricity self-sufficiency and self-consumption. We present a fuzzy logic-based energy management system which optimises the state of charge of the energy storage solution considering local electricity production and loads along with the contracted electric tariff. The methodology is tested in a PED comprising 360 households in Bilbao (a city in the north of Spain), setting various scenarios, including changes in the size of the electric storage, long-term climate change effects, and extreme changes in the price of energy carriers. The study revealed that the assessed PED could reach up to 75.6% self-sufficiency and 76.8% self-consumption, with climate change expected to improve these values. On economic aspects, the return on investment of the proposal ranges from 6 up to 12 years depending on the configuration choice. Also, the case that boosts the economic viability is tight to non-business as usual (BaU), whichever event spiked up the prices or climate change conditions shortens the economic variables. The average bill is around 12.89 EUR/month per house for scenario BaU; meanwhile, a catastrophic event increases the bill by as much as 76.7%. On the other hand, climate crisis events impact energy generation, strengthening this and, as a consequence, slightly reducing the bill by up to 11.47 EUR/month.

The influence of benzene on the composition, diversity and performance of the anodic bacterial community in glucose-fed microbial fuel cells.

Bioelectrochemical systems offer unique opportunities to remove recalcitrant environmental pollutants in a net positive energy process, although it remains challenging because of the toxic character of such compounds. In this study, microbial fuel cell (MFC) technology was applied to investigate the benzene degradation process for more than 160 days, where glucose was used as a co-metabolite and a control. We have applied an inoculation strategy that led to the development of 10 individual microbial communities. The electrochemical dynamics of MFC efficiency was observed, along with their 1H NMR metabolic fingerprints and analysis of the microbial community. The highest power density of 120 mW/m2 was recorded in the final period of the experiment when benzene/glucose was used as fuel. This is the highest value reported in a benzene/co-substrate system. Metabolite analysis confirmed the full removal of benzene, while the dominance of fermentation products indicated the strong occurrence of non-electrogenic reactions. Based on 16S rRNA gene amplicon sequencing, bacterial community analysis revealed several petroleum-degrading microorganisms, electroactive species and biosurfactant producers. The dominant species were recognised as Citrobacter freundii and Arcobacter faecis. Strong, positive impact of the presence of benzene on the alpha diversity was recorded, underlining the high complexity of the bioelectrochemically supported degradation of petroleum compounds. This study reveals the importance of supporting the bioelectrochemical degradation process with auxiliary substrates and inoculation strategies that allow the communities to reach sufficient diversity to improve the power output and degradation efficiency in MFCs beyond the previously known limits. This study, for the first time, provides an outlook on the syntrophic activity of biosurfactant producers and petroleum degraders towards the efficient removal and conversion of recalcitrant hydrophobic compounds into electricity in MFCs.

The Difference between Plasmon Excitations in Chemically Heterogeneous Gold and Silver Atomic Clusters.

Weak doping can broaden, shift, and quench plasmon peaks in nanoparticles, but the mechanistic intricacies of the diverse responses to doping remain unclear. In this study, we used the time-dependent density functional theory (TD-DFT) to compute the excitation properties of transition-metal Pd- or Pt-doped gold and silver atomic arrays and investigate the evolution characteristics and response mechanisms of their plasmon peaks. The results demonstrated that the Pd or Pt doping of the off-centered 10 × 2 atomic arrays broadened or shifted the plasmon peaks to varying degrees. In particular, for Pd-doped 10 × 2 Au atomic arrays, the broadened plasmon peak significantly blueshifted, whereas a slight red shift was observed for Pt-doped arrays. For the 10 × 2 Ag atomic arrays, Pd doping caused almost no shift in the plasmon peak, whereas Pt doping caused a substantial red shift in the broadened plasmon peak. The analysis revealed that the diversity in these doping responses was related to the energy positions of the d electrons in the gold and silver atomic clusters and the positions of the doping atomic orbitals in the energy bands. The introduction of doping atoms altered the symmetry and gap size of the occupied and unoccupied orbitals, so multiple modes of single-particle transitions were involved in the excitation. An electron transfer analysis indicated a close correlation between excitation energy and the electron transfer of doping atoms. Finally, the differences in the symmetrically centered 11 × 2 doped atomic array were discussed using electron transfer analysis to validate the reliability of this analytical method. These findings elucidate the microscopic mechanisms of the evolution of plasmon peaks in doped atomic clusters and provide new insights into the rational control and application of plasmons in low-dimensional nanostructures.

TRNSYS Simulation of a Bi-Functional Solar-Thermal-Energy-Storage-Assisted Heat Pump System

The escalating energy demands in buildings, particularly for heating and cooling demands met by heat pumps, have placed a growing stress on energy resources. The bi-functional thermal diode tank (BTDT) is proposed as thermal energy storage to improve the heating and cooling performances of heat pumps in both summer and winter. The BTDT is an insulated water tank with a gravity heat pipe (GHP), which can harvest and store heat passively from sun radiation and the external environment during the daytime. In summer, it harvests and stores cold energy from the air and night sky during the daytime. The performance of the BTDT-assisted heat pump (BTDT-HP) system in Adelaide, Australia, during the 2021–2022 summer and winter seasons was evaluated by conducting a TRNSYS simulation. This study revealed that the BTDT-HP system outperformed the reference ASHP system, where up to 8% energy in heating and 39.75% energy in cooling could be saved. An overall reduction in the energy consumption of 18.89% was achieved. Increasing the BTDT volume and GHP panel area enabled the tank to store more thermal and cold energy across the winter and summer seasons, thereby improving the system’s performance. The maximum ESPs were found to be 31.6% and 41.2% for heating and cooling for the study case under optimal conditions. When the GHP panel area was fixed at 15 m2, the BTDT volume should be at least 28 m3 for the BTDT-HP system, boasting cooling and heating capacities of 40 kW and 43.2 kW, to achieve positive energy savings.

Integrating Internet of Things (IoT) Approach to Post-Occupancy Evaluation (POE): An Experimental At-the-Moment Occupant Comfort Control System

This paper describes an empirical experiment of Internet of Things (IoT)’s integration in the Post-Occupancy Evaluation (POE) process. The experiment aimed to trial a novel IoT approach to enabling building user responsiveness to prevalent IEQ for individualised comfort. The purpose is to provide a system that mitigates a common issue of centralised air conditioning that limits occupants’ control over their immediate environment. To achieve this, an IoT platform was developed with smart IEQ monitoring sensors and wearable devices and trialled with PhD researchers in a shared university workspace. The findings provided empirical evidence of IoT’s enhanced benefits to improving user control over their individual comfort and enabling positive energy behaviour in buildings. Specifically, the IoT system provided real-time insight into CO2 concentration data while enabling responsive occupant interaction with their immediate environment and at-the-moment mitigation actions. Outputs of the experiment showed that the perceptions of participants about the stuffiness of the air, productivity, and healthy environment were significantly better after taking the mitigation action compared to before. Also, we found a significant relationship between measured CO2 concentration readings and perceived air stuffiness (p = 0.004) and productivity (p = 0.006) and a non-significant relationship between CO2 concentration readings and perceived healthy environment (p = 0.058). Interestingly, we observed that irrespective of the similarities in recorded CO2 concentration readings being within acceptable ranges (632–712 ppm), the perception of air stuffiness significantly differed (p = 0.018) before and after the mitigation actions. The effectiveness of the developed IoT platform was evidenced as most of the participants found the process very easy to participate in with little interruptions to their work as little time was consumed. The results are useful in modifying approaches to building occupant comfort and energy behaviour in commercial and residential settings.

Advanced design of sol-gel derived multilayered cerium titanate films: structural, surface, photoelectrochemical and photocatalytic properties

Crystallization of Ce2Ti2O7 in the mixture of TiO2 and CeO2 was achieved by the three-layered coating of cerium − titanium mixed sol of the 1 : 1 metals molar ratio on a glass substrate at certain temperature regime in air as proven by XRD, SAED and Raman spectroscopy. Anatase and Ce2Ti2O7 crystallization with XRD undetectable crystallites brought to the increase of the specific surface area of the films. The formation of Ti–O–Ce bonds on the surface of the films was proven by the noticeable shift of Ti2p and O1s XPS maxima compared to TiO2 ones. The additional peaks in Ti2p, O1s and Ce3d XPS spectra belonging to the common bonds between the metals ions were identified for the first time. The bandgap energy and band-edge positions of Ce2Ti2O7 were firstly determined by photoelectrochemical measurements. The inactivity of the films in photocatalytic reductive and oxidative processes was caused by the unfavorable position of the valence band of Ce2Ti2O7 causing the recombination of the photo-formed electron−hole pair.

A micromagnetic-mechanically coupled phase-field model for fracture and fatigue of magnetostrictive alloys

Magnetostrictive alloys are usually brittle materials with micromagnetic structures. Their structural reliability and durability depend on the complex micromagnetic-mechanical coupling at smaller length scales encompassing the evolution of micromagnetic structures. Herein we propose a micromagnetic-mechanically coupled phase-field model for fracture and fatigue behavior of magnetostrictive alloys with evolution of the micromagnetic structure. The thermodynamically-consistent model is derived from microforce theory, laws of thermodynamics, and Coleman–Noll analysis. The evolution of crack phase-field and magnetization-vector order parameters that are fully coupled is governed by history field dependent Allen–Cahn and Landau–Lifshitz–Gilbert equations, respectively. The model is extended to fatigue by introducing a degradation prefactor for the fracture energy as a function of positive elastic energy. One-dimensional analyses are then presented to anatomize the crack driving forces in terms of fully coupled micromagnetic-mechanical and pure mechanical driving force. We demonstrate the model capabilities by finite-element numerical studies on the micromagnetic domain evolution during the crack propagation and the influence of external magnetic field for type-I, type-II, and three-point bending fracture, as well as for the fracture of a single-edge notched specimen with an elliptical inclusion. The simulation result shows that depending on how micromagnetic domains are switched under micromagnetic-mechanical coupling, the magnetic field can enhance or decrease the critical load. In the presence of inclusion with larger fracture toughness, a crack is found to nucleate in the tri-junction of multi-domain micromagnetic structure owing to the high elastic strain around the tri-junction point. It is further found that a suitable magnetic field promoting magnetization-vector rotation around the crack tip could remarkably improve the fracturing load and fatigue life. The results demonstrate the model promising for the study of micromagnetic-mechanically coupled fracture and fatigue in magnetostrictive alloys.

The subcutaneous adipose transcriptome identifies a molecular signature of insulin resistance shared with visceral adipose.

The objective of this study was to identify the transcriptional landscape of insulin resistance (IR) in subcutaneous adipose tissue (SAT) in humans across the spectrum of obesity. We used SAT RNA sequencing in 220 individuals with metabolic phenotyping. We identified a 35-gene signature with high predictive accuracy for homeostatic model of IR that was expressed across a variety of non-immune cell populations. We observed primarily "protective" IR associations for adipocyte transcripts and "deleterious" associations for macrophage transcripts, as well as a high concordance between SAT and visceral adipose tissue (VAT). Multiple SAT genes exhibited dynamic expression 5 years after weight loss surgery and with insulin stimulation. Using available expression quantitative trait loci in SAT and/or VAT, we demonstrated similar genetic effect sizes of SAT and VAT on type 2 diabetes and BMI. SAT is conventionally viewed as a metabolic buffer for lipid deposition during positive energy balance, whereas VAT is viewed as a dominant contributor to and prime mediator of IR and cardiometabolic disease risk. Our results implicate a dynamic transcriptional architecture of IR that resides in both immune and non-immune populations in SAT and is shared with VAT, nuancing the current VAT-centric concept of IR in humans.