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Natural fibers such as coir fibers have been increasingly explored as reinforcement in the cementitious composite to promote sustainable and economical construction. However, the in-situ application of this composite presents challenges due to the complex interplay of water behaviors, involving the hydrophilicity of natural fibers, the hydration of cement and the evaporation due to drying. Although these water-related processes play a crucial role in achieving the desired properties, they have been relatively underreported in the literature. This study aims to investigate the role of coir fibers in the water distribution and pore size distribution during the early age (initial 3 days) of cement paste hydration under drying conditions. Accordingly, Nuclear Magnetic Resonance (NMR) methods involving the moisture profiling and transverse relaxation are used to monitor the water distribution and pore size distribution in time but also in space. The samples are made by adding water-saturated coir fibers to the cement paste at different dosages (0, 1%, 2% and 4%). The effects of drying and coir fiber dosages on the samples are evaluated. The results show that drying leads to a moisture gradient and a larger transverse relaxation time T 2, i.e., a coarser pore structure near the drying surface. By adding the saturated coir fibers, the moisture gradient caused by drying is decreased and spread out along the sample. As the coir fiber content increases, the water content along the sample and the total water content of the sample increase. As a result, the samples with coir fibers exhibit a lower T 2, i.e., a denser pore structure near the drying surface. Coir fibers are shown to eliminate the adverse effect of drying on cement hydration through three effects, including the internal curing, improved water transport and crack control. The results from this study reveal the promising potential of coir fibers for in-situ construction applications.

Surface passivation has been demonstrated to be an effective strategy to reduce defects of hybrid halide perovskite films for making efficient and stable perovskite solar cells (PSCs). Especially the strong interaction between the passivation agents and the perovskite films is favorable for achieving a durable passivation effect. Pyridine derivatives with bidentate anchoring groups can interact with the uncoordinated Pb2+and minimize perovskite defects. Herein, in order to rationally design bidentate passivation agents, the passivation effects of pyridine (Py) and its derivatives (Py-X) with different functional groups of amino, carboxyl acid, and aldehyde are compared in carbon-based perovskite solar cells (C-PSCs) for the first time. Py-NH2is found to passivate the perovskite CH3NH3PbI3film the best among all the passivation agents. The N atoms on both the pyridine ring and the amino group with lone pair electrons can combine with the uncoordinated Pb2+, effectively reducing the defect density in the Py-NH2-treated perovskite film. First-principles density functional theory (DFT) calculations reveal that the strong interaction between Py-NH2and CH3NH3PbI3strengthens Pb-I bond and hinders the formation of I vacancies. Carbon-based perovskite solar cells (C-PSCs) passivated by Py-NH2achieve a champion power conversion efficiency (PCE) of 14.75%, compared to 11.55% of the control device. The Py-NH2passivated C-PSCs also exhibit good long-term stability, retaining more than 90% of the initial efficiency after 30 days of storage in air with 35-45% relative humidity.

Defects in CH3NH3PbI3 perovskites, oxygen species in the air, and local charges play a significant role in the long-term stability of perovskites. However, the interplay of these factors are complex and their role in the degradation of perovskites at the atomistic level is not well understood. By using density functional theory calculations and chemical bonding analysis, we study the effect of oxygen and local charges on the degradation of perovskites. We find that the easier formation of I vacancies upon oxygen and the accelerated degradation of CH3NH3PbI3 by excess electrons via the formation of peroxide species. The creation of peroxide disintegrates the lattice of perovskites on the surfaces and possibly induces a cascade of degradation reactions that eventually destruct the perovskite lattices. We further demonstrate that the addition of holes are beneficial to prevent the formation of the peroxide, therefore can potentially improve the stability of the perovskites. (Figure presented.).

This work proposes a new stochastic gas–solid scattering model for diatomic gas molecules constructed based on the collisional data obtained from molecular dynamics (MD) simulations. The Gaussian mixture (GM) approach, which is an unsupervised machine learning approach, is applied to H2 and N2 gases interacting with Ni surfaces in a two-parallel wall system under rarefied conditions. The main advantage of this approach is that the entire translational and rotational velocity components of the gas molecules before and after colliding with the surface can be utilized for training the GM model. This creates the possibility to study also highly nonequilibrium systems and accurately capture the energy exchange between the different molecular modes that cannot be captured by the classical scattering kernels. Considering the MD results as the reference solutions, the performance of the GM-driven scattering model is assessed in comparison with the Cercignani–Lampis–Lord (CLL) scattering model in different benchmarking systems: the Fourier thermal problem, the Couette flow problem, and a combined Fourier–Couette flow problem. This assessment is performed in terms of the distribution of the velocity components and energy modes, as well as accommodation coefficients. It is shown that the predicted results by the GM model are in better agreement with the original MD data. Especially, for H2 gas the GM model outperforms the CLL model. The results for N2 molecules are relatively less affected by changing the thermal and flow properties of the system, which is caused by the presence of a stronger adsorption layer.

Wettability is one of the key controlling parameters for multiphase flow in porous media, and paramount for various geoscience applications. While a general awareness of the importance of wettability was established decades ago, our fundamental understanding of how wettability influences transport and of how to characterize wettability has improved tremendously in recent years through breakthroughs in imaging technology and modeling techniques. Numerical modeling studies clearly show not only that macroscopic two-phase flow is influenced by the average wettability, but also that the spatial distribution of wetting significantly impacts the macroscopic parameters. Herein, we explore the thermodynamics for porous multiphase systems, and recent breakthroughs in wettability characterization. Our view is that bridging the multiscale characterization of wetting must consider two fundamental perspectives: geometry and energy. Advancing the overall description requires an improved understanding of the operative mechanisms that dominate at various scales, and the development of quantitative approaches to capture these effects. We take a multistage approach, looking at these fundamental perspectives from the sub-pore-to-pore length scales, followed by the pore-to-core length scales using various analytical techniques and numerical simulations. Within this context, there remain many open-ended questions, and we therefore highlight these issues to provide guidance on future research directions. Our overall aim is to provide comprehensive guidance on the multiscale characterization of wettability in porous media, in order to facilitate novel research.

The COVID-19 pandemic, caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is not showing any sign of slowing down even after the ongoing efforts of vaccination. The threats of new strains are concerning, as some of them are more infectious than the original one. A therapeutic against the disease is, therefore, of urgent need. Here, we use the DrugBank database to screen for potential inhibitors against the 3CL pro main protease of SARS-CoV-2. Instead of using the traditional approach of computational screening by docking, we developed a kernel ridge regressor (using a part of the docking data) to predict the binding energy of ligands. We used this model to screen the DrugBank database and shortlist two lead candidates (bromocriptine and avoralstat) for in vitro enzymatic study. Our results show that the 3CL pro enzyme activity in presence of 100 μM concentration of bromocriptine and avoralstat is 9.9% and 15.9%, respectively. Remarkably, bromocriptine exhibited submicromolar IC50 of 130 nM (0.13 μM). Avoralstat showed an IC50 of 2.16 μM. Further, the interactions of both drugs with 3CL pro were analyzed using molecular dynamics simulations of 100 ns. Results indicate that both ligands are stable in the binding pocket of the 3CL pro receptor. In addition, the MM-PBSA analysis revealed that bromocriptine (-29.37 kcal/mol) has a lower binding free energy compared to avoralstat (-6.91 kcal/mol). Further, hydrogen bond analysis also showed that bromocriptine interacts with the two catalytic residues, His41 and Cys145, more frequently than avoralstat. Communicated by Ramaswamy H. Sarma.

Scalar transport (e.g. heat or chemical species) in laminar flows is key to many industrial activities and fluid stirring by flow reorientation is a common way to enhance this process. However, "How best to stir?" remains a major challenge. This study aims to contribute to existing solutions by the development of a dedicated flow-control strategy for the fast heating of a cold fluid via a hot boundary in a representative case study. Fluid deformation acts as the "thermal actuator" via which the flow affects heat transfer yet this may both enhance and diminish heat exchange between fluid parcels and thus restricts the beneficial impact of flow. Moreover, the impact of fluid deformation on the global fluid heating is primarily confined to the proximity of the moving boundary that drives the flow. These insights make incorporation of thermal behaviour essential for effective flow-based enhancement strategies and expose fluid mixing, the conventional approach in industry, as potentially sub-optimal. The notion that global heating encompasses two concurrent processes, i.e. increasing energy content and thermal homogenisation, yields the relevant metrics for the formulation of the control problem as the minimisation of a dedicated cost function. This facilitates step-wise determination of the "best" flow reorientation from predicted future evolutions of actual intermediate states and thereby paves the way to (real-time) regulation of scalar transport by flow control. Performance analyses reveal that this "adaptive flow reorientation" significantly accelerates fluid heating and thus is superior to conventional periodic schemes (designed for efficient fluid mixing) both in consistency and effectiveness. The controller in fact never selects these periodic schemes and achieves the same superior performance for all flow conditions irrespective of whether said mixing occurs., Comment: 34 pages, 17 figures

Nuclear Magnetic Resonance (NMR) is used to study the early-age hydration as well as autogenous shrinkage and drying shrinkage of cement paste with the addition of coir fibers. The dosage and water content of coir fibers are evaluated. The results show that added coir fibers have a negligible influence on cement hydration kinetics. However, the internal curing effect of saturated coir fibers and water competition induced by dry fibers are visualized. As the saturated fiber content increases, autogenous shrinkage and drying shrinkage decrease due to the internal curing and reinforcing effects of fibers. Dry fibers generate more autogenous shrinkage but less drying shrinkage than saturated fibers of the same dosage due to the introduced water competition. NMR is proven able to track water transportation and shrinkage in cement composites.

Greenhouse horticulture cultivates vegetables, fruits, and flowers in protected glass houses. Approximately 65%-85% of the total energy in greenhouses is used for heating. To reach the climate goals energy reduction is needed. Energy savings cannot only be achieved by improving the insulation value of the greenhouse covers since also the relative humidity of indoor air needs to stay below a critical humidity level to avoid fungus growth. Therefore ventilation is required with an average air change rate (ACH) of 2.5/h. This is often realized by (partly) opening and closing the glass greenhouse cover thereby losing part of the heat. In this paper, we focus on a novel method that improves the thermal insulation of transparent top covers and/or walls while ensuring sufficient ventilation: transparent dynamic insulation (TDI). TDI is based on a concept called Dynamic Insulation, also known as a "breathing wall": infiltrating air flows through the multi-layer insulation panel. While doing this, the incoming air takes up part of the heat and uses this for pre-heating. Thereby it reduces the overall heat transfer value (U-value) and provides pre-warmed, fresh air flow into the greenhouse. The main difference compared to “traditional” dynamic insulation is that its design is transparent for solar irradiation and therefore can be used for greenhouses. In this paper, we show experimental results on a TDI prototype panel using a hot box apparatus with an ACH=2.5/h and prescribed temperature differences between indoor and outdoor of ΔT=10C and ΔT=20C. It is shown that the measured overall U-value for the TDI panel is about 19% lower than for double glass and more than a factor 2 lower than single-layered Hortiplus glass. Therefore it is concluded that TDI is a promising approach to reducing energy consumption in greenhouse horticulture while ensuring sufficient air refreshment for moisture control.

The stability of metal-organic frameworks is a key factor in many applications in some fields that require working under harsh conditions. It is known that a large number of MOFs are vulnerable to humid air. It means that when they are exposed to water, a structural collapse of the crystal happens. In this work, Molecular Dynamics simulations using a reactive force field have been performed to study the stability of MOF-74 against the adsorption of catechol, resorcinol and hydroquinone in the presence of water. We reproduced the water instability of Zn-MOF-74 and we studied the resistance of the structure. Our simulations showed that the three isomers generate a volume change in the framework but the structural collapse does not happen. In contrast, for water-isomer mixtures, there is structural collapse. Not only do catechol, resorcinol and hydroquinone not behave as stabilizing agents but they do enhance the hydration effect on the structure.

This paper presents systematic analysis of value creation chains and their economic and environmental hotspots within a multi-product biorefinery with the primary goal to promote sustainable biorefining. Lignocellulosic biorefinery producing ethanol, crude lignin oil (CLO) and electricity was analysed. The methodology involves transformation of technological model into an input-output one with the use of matrix notation for the analysis of economic and environmental attributes along value chains. The results show that the accumulation of biomass through energy supply grows by a factor of 1.2 for ethanol and electricity, and by 1.4 for CLO value chains, of which solid recovery, lignin solvolysis and biomass pretreatment are responsible for the most significant growth indicating the necessity for energy optimization of those steps. The analysis reveals a superfluous role of infrastructure in pretreatment and lignin drying processes. Of infrastructural costs related to the equipment required for the pretreatment step, wastewater treatment (WWT) facility is responsible for 58%, and of the costs of lignin drying, the combined heat and power plant is responsible for 56%. WWT determines 75% of infrastructural GHG emissions attributable to pretreatment, and 57% of those related to lignin drying. This points at an advantage of a biorefinery concept involving the removal of lignin fraction before the valorization of carbohydrates. Another hotspot, the lignin solvolysis technology, shows environmental and economic advantages of its further optimization in terms of production costs and GHG emissions. The proposed method is helpful for analyzing economic and environmental hotspots in new biorefinery concepts and integration pathways.

Potassium carbonate (K2 CO3 ) is a promising material for the long-term storage of renewable energy. A reactor vessel filled with K2 CO3 can potentially be used as a domestic heat battery. The hydration and dehydration reactions of salt hydrates in a reactor vessel are generally described using a one-process model, such as the ‘Arrhenius-f (α)’ model. However, this modeling approach cannot always be applied correctly. If the reaction does not proceed in a pseudo-steady state, and/or when nucleation and growth processes are simultaneously active during the transformation from an anhydrous to a hydrated state, the one-process modeling approach should not be applied. In this paper, it is investigated using simultaneous thermal analysis (STA) experiments whether the pseudo-steady state approximation is valid during the hydration reaction of K2 CO3 . Additionally, ‘jump experiments’ using STA are employed to investigate the rate-determining step (RDS) of the hydration reaction by applying step-wise changes in partial water vapor pressure. The presence of nucleation and growth processes during the hydration reaction is investigated by fitting isotropic models to STA data. The STA results showed that indeed the hydration of K2 CO3 happens in a pseudo-steady state, and the reaction can be described using a RDS. An isotropic nucleation and growth model shows that the hydration reaction can be described by assuming instantaneous nucleation followed by diffusion-limited growth. This leads to the general conclusion that the one-process modeling approach, such as the Arrhenius-f (α) model, is valid to describe the hydration reaction of K2 CO3 particles.

HypothesisHigh molecular weight polymers are widely used in oilfield applications, such as in chemical enhanced oil recovery (cEOR) technique for hydrocarbon recovery. However, during flow in a porous rock, polymer retention is usually a major challenge, as it may result in the decrease of polymer concentration or lead to plugging of pores with significant permeability reduction and injectivity loss. Hence, an understanding of the retention mechanisms will have a profound effect in optimizing the process of polymer flooding, in particular, for carbonate rocks, which hold more than half of the world's oil reserves. Therefore, in this study, the retention of hydrolysed polyacrylamide (HPAM) polymer, a commonly used chemical for EOR, is investigated during flow in Estaillades carbonate rock.ExperimentsA novel approach of investigating HPAM retention in Estaillades carbonate rock was carried out using Atomic force microscopy (AFM). Since Estaillades carbonate rock is ∼98% calcite, HPAM retention was first characterised on a cleaved flat calcite mineral surface after immersing in HPAM solution. Afterwards, HPAM was flooded in Estaillades carbonate to observe the effect of flow dynamics on the retention mechanisms.FindingsWe find that the dominant mechanism for retention of HPAM on calcite after fluid immersion is polymer adsorption, which we believe is driven by the electrostatic interaction between the calcite surface and the solution. The thickness of the adsorbed layer on calcite is beyond 3 ​nm suggesting it is not adsorbed only flat on the surface. Different types of adsorbed layers were formed representing trains, and the more extended loops or tails with the largest polymer layer thickness about 35 ​nm, representing the longer loops or tails. Layers of this thickness will begin to impair the permeability of the rock. However, in Estaillades, thicker adsorbed layers are observed in different regions of the rock surface ranging between 50 and 350 ​nm. We suggest that this is due to either mechanical entrapment and/or polymer entanglement during flow in Estaillades carbonate rock, which will cause the major permeability impairment in porous rocks.

Hypothesis: The macroscopic movement of subsurface fluids involved in CO2 storage, groundwater, and petroleum engineering applications is controlled by interfacial forces in the pores of rocks. Recent advances in modelling these systems has arisen from approaches simulating flow through a digital representation of the complex pore structure. However, further progress is limited by difficulties in characterising the spatial distribution of the wetting state within the pore structure. In this work, we show how observations of the fluid coverage of mineral surfaces within the pores of rocks can be used as the basis for a quantitative 3D characterisation of heterogeneous wetting states throughout rock pore structures. Experiments: We demonstrate the approach with water–oil fluid pairs on rocks with distinct lithologies (sandstone and carbonate) and wetting states (hydrophilic, intermediate wetting, and heterogeneously wetting). Findings: Fluid surface coverage the within rock pores is a robust signal of the wetting state across varying rock types and wetting states. The wetting state can be quantified and the resulting 3D maps can be used as a deterministic input to pore scale models. These may be applied to multiphase flow problems in porous media ranging from soil science to fuel cells.

Life‐cycle inventory (LCI) is a fundamental phase in the quantification of the environmental performance of products. However, when it comes to the LCI of a multi‐product system, discussions about the choice of the appropriate methodology to allocate environmental impacts still continue. A further system subdivision and the implementation of a mechanism allowing environmental burdens to be tracked would help to improve model accuracy. This study focuses on the LCI modeling of a lignocellulosic biorefinery producing ethanol, lignin oligomers, and electricity, and demonstrates the application of the matrix‐based approach for detailed system subdivision and environmental burden tracking. Forty scenarios utilizing process‐specific allocation methods were tested to account for the global warming potential of outputs. The main findings of the paper are: (i) the importance of specific allocation methods applied to combined heat and power plants that stress the key role of internal energy supply in carrying environmental burdens; (ii) a negligible effect of allocation methods applied to wastewater treatment facilities; (iii) the inconsistency of results obtained via two allocation methods, one based on the total mass and the second based on the dry mass allocation, which raises questions about the validity of water accounting in the allocation procedure of related products; (iv) the role of upstream greenhouse gas (GHG) emissions in lignin‐derived outputs, which emphasizes the importance of a proper allocation methodology to be applied to this residue; and (v) an important role of the biomass pretreatment and lignin solvolysis processes in the accumulation of emissions, which highlights the importance of decreasing the amount of solids and methanol content in the processes discussed here.

Hypothesis Roughness is an important parameter in applications where wetting needs to be characterized. Micro-computed tomography is commonly used to characterize wetting in porous media but the main limitation of this approach is the incapacity to identify nanoscale roughness. Atomic force microscopy, AFM, however, has been used to characterize the topography of surfaces down to the molecular scale. Here we investigate the potential of using AFM to characterize wetting behavior at the nanoscale. Experiments Droplets of water on cleaved calcite under decane were imaged using quantitative imaging QI atomic force microscopy where a force-distance curve is obtained at every pixel. Findings When the AFM tip passed through the water droplet surface, an attraction was observed due to capillary effects, such that the thickness of the water film was estimated and hence the profile of the droplet obtained. This enables parameters such as the contact angle and contact angle distribution to be obtained at a nanometer scale. The contact angles around the 3-phase contact line are found to be quasi-symmetrically distributed between 10–30°. A correlation between the height profile of the surface and contact angle distribution demonstrates a quasi-proportional relationship between roughness on the calcite surface and contact angle.

Core flooding experiments to determine multiphase flow in properties of rock such as relative permeability can show significant fluctuations in terms of pressure, saturation, and electrical conductivity. That is typically not considered in the Darcy scale interpretation but treated as noise. However, in recent years, flow regimes that exhibit spatio-temporal variations in pore scale occupancy related to fluid phase pressure changes have been identified. They are associated with topological changes in the fluid configurations caused by pore-scale instabilities such as snap-off. The common understanding of Darcy-scale flow regimes is that pore-scale phenomena and their signature should have averaged out at the scale of representative elementary volumes (REV) and above. In this work, it is demonstrated that pressure fluctuations observed in centimeter-scale experiments commonly considered Darcy-scale at fractional flow conditions, where wetting and non-wetting phases are co-injected into porous rock at small (−6) capillary numbers are ultimately caused by pore-scale processes, but there is also a Darcy-scale fractional flow theory aspect. We compare fluctuations in fractional flow experiments conducted on samples of few centimeters size with respective experiments andin-situmicro-CT imaging at pore-scale resolution using synchrotron-based X-ray computed micro-tomography. On that basis we can establish a systematic causality from pore to Darcy scale. At the pore scale, dynamic imaging allows to directly observe the associated breakup and coalescence processes of non-wetting phase clusters, which follow “trajectories” in a “phase diagram” defined by fractional flow and capillary number and can be used to categorize flow regimes. Connected pathway flow would be represented by a fixed point, whereas processes such as ganglion dynamics follow trajectories but are still overall capillary-dominated. That suggests that the origin of the pressure fluctuations observed in centimeter-sized fractional flow experiments are capillary effects. The energy scale of the pressure fluctuations corresponds to 105-106times the thermal energy scale. This means the fluctuations are non-thermal. At the centimeter scale, there are non-monotonic and even oscillatory solutions permissible by the fractional flow theory, which allow the fluctuations to be visible and—depending on exact conditions—significant at centimeter scale, within the viscous limit of classical (Darcy scale) fractional flow theory. That also means that the phenomenon involves both capillary aspects from the pore or cluster scale and viscous aspects of fractional flow and occurs right at the transition, where the physical description concept changes from pore to Darcy scale.

New homogeneous nucleation experiments are presented at 240 K for water in carrier gas mixtures of nitrogen with carbon dioxide molar fractions of 5%, 15%, and 25%. The pulse expansion wave tube is used to test three different pressure conditions, namely, 0.1, 1, and 2 MPa. In addition, a restricted series of nucleation experiments is presented for 25% carbon dioxide mixtures at temperatures of 234 and 236 K at 0.1 MPa. As pressure and carbon dioxide content are increased, the nucleation rate increases accordingly. This behavior is attributed to the reduction in the water surface tension by the adsorption of carrier gas molecules. The new data are compared with theoretical predictions based on the classical nucleation theory and on extrapolations of empirical surface tension data to the supercooled conditions at 240 K. The extrapolation is carried out on the basis of a theoretical adsorption/surface tension model, extended to multi-component mixtures. The theoretical model appears to strongly overestimate the pressure and composition dependence. At relatively low pressures of 0.1 MPa, a reduction in the nucleation rates is found due to an incomplete thermalization of colliding clusters and carrier gas molecules. The observed decrease in the nucleation rate is supported by the theoretical model of Barrett, generalized here for water in multi-component carrier gas mixtures. The temperature dependence of the nucleation rate at 0.1 MPa follows the scaling model proposed by Hale [J. Chem. Phys. 122, 204509 (2005)].

In rarefied gas flows, discontinuity phenomena such as velocity slip and temperature jump commonly appear in the gas layer adjacent to a solid boundary. Due to the physical complexity of the interactions at the gas-solid interface, particularly in the case of systems with local nonequilibrium state, boundary models with limited number of parameters cannot completely describe the reflection of gas molecules at the boundary. In this work, the Gaussian mixture (GM) model, which is an unsupervised machine learning technique, is employed to construct a statistical gas-solid surface scattering model based on the collisional data obtained from molecular dynamics (MD) simulations. The GM model is applied to study Couette flow for different inert gases (Ar and He) confined between two parallel infinite gold walls at different temperatures. A direct comparison between the results obtained from the GM model and the Cercignani-Lampis-Lord (CLL) scattering kernel against the MD collisional data in terms of the distribution of the predicted postcollisional velocities, and accommodation coefficients has shown that the results from the GM model are an excellent match with the MD results outperforming the CLL scattering kernel. As an example, for He gas, while the predicted energy accommodation coefficient by the CLL model is more than two times higher than the MD predictions, the value computed by the GM model is in excellent agreement with the MD results. This superior performance of the GM model confirms its high potential to derive a generalized boundary condition in systems encountered with highly nonequilibrium and complex gas flow conditions.

Methanol is considered to be a viable option for reducing greenhouse gas (GHG) emissions in shipping, the second-highest emitter after road freight. However, the use of fossil methanol is insufficient to meet climate change targets, while renewable methanol is yet unavailable on a commercial scale. This paper presents a novel biorefinery concept based on biomass solvolysis to produce crude lignin oil (CLO) from forest residues, a drop-in biofuel for methanol-propelled ships, and evaluates its environmental and economic profiles. In the base scenario, CLO can achieve emission saving of 84% GHG compared to fossil alternatives, and a minimum selling price (MSP) of $821 per ton of methanol equivalent (ME), i.e., within the range of the current bio-methanol production costs. The emission of GHGs of co-produced ethanol can be reduced by 67% compared to fossil analogues. The increase of renewable electricity share to 75% is capable of shrinking emissions by 1/5 vs. the base case, while fossil methanol losses, e.g., of that in cellulose pulp, can boost emissions by 63%. Low-pressure steam use in the biomass pretreatment, as well as biorefinery capacity increase by a factor of 2.5, have the greatest potential to reduce MSP of CLO to $530 and $614 per ton of ME, respectively.

The slow progress in the commercialization of lignocellulosic biorefineries involving the biochemical conversion pathway points at the immaturity of existing biorefinery concepts. The current research suggests a systematic analysis of value creation chains and their economic and environmental hotspots within a multi-product biorefinery, having as the primary goal to promote sustainable biorefining processes. A lignocellulosic biorefinery producing ethanol, crude lignin oil and electricity was analyzed. Our methodology involves the transformation of a technological biorefinery model into the input-output one and the use of matrix notation to track the accumulation of economic and environmental attributes along biorefinery value chains. Three categories of indicators are chosen to reveal the most critical processing stages of every value chain, namely: (i) monetary and environmental profiles, (ii) the role of feedstock and (iii) infrastructure required to support main processes. Principal biorefinery hotspots refer to the biomass pretreatment, solids recovery and lignin drying stages, which is due mainly to wastewater treatment accompanying these processes. The other hotspot, lignin solvolysis technology, shows the environmental advantage of decreasing methanol content in the produced lignin oil. The proposed method is worth being applied to the analysis of new biorefinery concepts and new integration pathways.

In this chapter on simulation techniques for thermochemical reactions in thermal energy storage systems the focus is mainly on molecular modeling techniques for the hydration and dehydration (sorption and desorption) processes occurring in salt hydrates at the nanoscale. Modeling techniques such as density function theory, molecular dynamics, and Monte Carlo are briefly introduced. Some attention is also given to micro- and macroscale modeling techniques used at larger length scales, such as Mampel’s model and the continuum approach. Before introducing all the length (and time) scales involved when modeling a heat storage system, a qualitative description is given of the hydration and dehydration processes on the nano/microscale.

The ingress of water-soluble aggressive species is a major cause to the reduced service life of concrete structures. Bulk modification by adding hydrophobic agents in the cementitious materials is commonly applied to reduce water penetration into the concrete matrix. However, conventional hydrophobic modifications of concrete are associated with several unresolved major drawbacks such as high cost and toxicity. Here, we investigate the impact of safe and easy-to-culture bacteria on the hydrophobic properties of concrete. We demonstrate that hydrophobic concrete can be conveniently created by using the liquid culture of bacteria without the need of growing biofilms as suggested by previous research, even with a strain that does not present innate hydrophobicity. These key findings greatly improve the feasibility for the large-scale application of water resistance cementitious materials. Scanning electron microscopy and X-ray diffraction analyses indicated higher levels of micro-calcite formations with the increased addition of bacteria. These micro-calcite structures account for the dramatic increase in surface roughness which leads to elevated hydrophobic properties of the hybrid concrete. This phenomenon is reminiscent of the “lotus-leaf effect”, with ultrahydrophobicity arising from the nano- and microscopic topologies of surfaces. Bacteria-modified cement presents distinct heat-flow profiles during hydration consistent with the increased calcite formation. Taken together, this research gives unprecedented mechanistic insight into the design of microbial-modified concrete with hydrophobic properties particularly useful in floating and offshore structures. Given the large repertoire of bacteria still to be used, our work sets the stage for the future design of microbial-based hydrophobic concrete that can be tailored with additional functions such as self-healing and odor removal.

This paper presents an estimation of the European (EU28) industrial heat pump market potential in terms of magnitude, sizing and number of units. This study is carried out in order to provide technology suppliers and manufacturers of industrial heat pumps perspectives for the technology. Potential heat pump applications in the food, paper, chemical and refining sectors are identified considering a maximum sink temperature of 200°C. This is achieved utilising a bottom-up methodology that uses detailed information from individual processes in the aforementioned sectors. Combining individual process data with typical plant capacities provides information on the heating capacities of heat pumps. The data is upscaled to European level, using production statistics relevant to the individual processes analysed. Since the database of processes is generic in nature and not fully covering the whole industrial sector, the results of this analysis provide a conservative estimate of the heat pump market potential. The results show a potential cumulative heating capacity of industrial heat pumps in EU28 of 23.0 GW, consisting of 4174 heat pump units which are able to cover 641 PJ/a of process heat demand. The largest number of heat pump units (%) can be found for heating capacities

Due to the requirement for developing more sustainable constructions, natural fibers from agricultural wastes, such as coir fibers, have been increasingly used as an alternative in concrete composites. However, the influence of coir fibers on the hydration and shrinkage of cement-based materials is not clear. In addition, limited information about the reinforcing mechanisms of coir fibers in concrete can be found. The goal of this research is to investigate the effects of coir fibers on the hydration reaction, microstructure, shrinkages, and mechanical properties of cement-based light-weight aggregate concrete (LWAC). Treatments on coir fibers, namely Ca(OH)2 and nano-silica impregnation, are applied to further improve LWAC. Results show that leachates from fibers acting as a delayed accelerator promote cement hydration, and entrained water by fibers facilitates cement hydration during the whole process. The drying shrinkage of LWAC is increased by adding fibers, while the autogenous shrinkage decreases. The strength and toughness of LWAC are enhanced with fibers. Finally, three reinforcement mechanisms of coir fibers in cement composites are discussed.

Biological tissues exhibit swelling or shrinking behaviour. This behaviour is caused by water binding. Biological tissues are able to bind water because of the fixed charges of the solid skeleton. These electrical charges are responsible for a variety of physical phenomena such as streaming potentials, diffusion potentials, electro-osmosis, electrophoresis and swelling.