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A liquid CO 2 ( l -CO 2 )–based coating technique is used for the pore-filling of a porous copper indium gallium sulfide (CuIn x Ga 1−x S 2 , CIGS) film synthesized by a solution-based method. In the l -CO 2 –based coating, copper and indium precursors dissolved in l -CO 2 are deposited on the porous copper indium gallium oxide film, followed by low-temperature sulfurization. After the high-temperature sulfurization of the deposited film with the l -CO 2 –based coating, a highly dense CIGS film with almost complete pore-filling is obtained. The use of an indium rich solution in l -CO 2 leads to the formation of near stoichiometric ratio of Cu:(In + Ga) that improves the pore filling behavior. [ABSTRACT FROM AUTHOR]

We report the simultaneous deposition of two different metal precursors dissolved in liquid carbon dioxide (l-CO2), aiming to the synthesis of ternary chalcopyrite (e.g. CuInS2) nanoparticles on a mesoporous TiO2 film. The l-CO2-based deposition of Cu and In precursors and subsequent reaction with a dilute H2S gas resulted in CuxInySz nanoparticles uniformly deposited across the entire thickness of a mesoporous TiO2 film. Further heat treatment (air annealing and sulfurization) led to the formation of more stoichiometric CuInS2 nanoparticles. The formation of CuInS2 on TiO2 was confirmed by scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction, and Raman spectroscopy. The crystal growth of CuInS2 was also found to be controllable by adjusting the number of coating cycles of the l-CO2-based deposition. [ABSTRACT FROM AUTHOR]

Highlights: [•] The concrete industry is responsible for about 10% of the greenhouse gas emissions. [•] The production of concrete with recycled constituents can reduce such an impact. [•] The influence of the aggregate replacement on the hydration process is investigated. [•] The relationship between concrete strength and hydration degree is shown. [•] The influence of initial moisture conditions of aggregates is particularly addressed. [Copyright &y& Elsevier]

Abstract: This paper deals with the correlation between the time evolution of the degree of hydration and the compressive strength of Recycled Aggregate Concrete (RAC) for different water to cement ratios and initial moisture conditions of the Recycled Concrete Aggregates (RCAs). Particularly, the influence of such moisture conditions is investigated by monitoring the hydration process and determining the compressive strength development of fully dry or fully saturated recycled aggregates in four RAC mixtures. Hydration processes are monitored via temperature measurements in hardening concrete samples and the time evolution of the degree of hydration is determined through a 1D hydration and heat flow model. The effect of the initial moisture condition of RCAs employed in the considered concrete mixtures clearly emerges from this study. In fact, a novel conceptual method is proposed to predict the compressive strength of RAC-systems, from the initial mixture parameters and the hardening conditions. [Copyright &y& Elsevier]

Abstract: This paper presents a sound theoretical formulation and an effective numerical implementation of a heat-flow and hydration model for concrete hardening. The model is based on the Fourier equation of heat flow with the adiabatic hydration curve employed as a reference for simulating the hydration heat source. The proposed formulations are based on a consistent scheme for the partial differential equation and its boundary and starting conditions. The hydration kinetics is simulated through the Arrhenius approach. Formulations for the compressive strength and the elastic modulus are provided and the maturity function is also considered. A finite difference numerical solution is derived with a forward explicit time integration in the time–space domain. The numerical solution is designed as a stepwise “recipe” specifically conceived to be easily implemented by means of either a high-level programming language or even a spreadsheet tool. Experimental temperature measurements for two different mixtures, under adiabatic and semi-adiabatic conditions, are used for validating the proposed model. The adiabatic and semi-adiabatic temperature simulations show good agreement with the experimental data for both concrete mixtures. The degree of hydration could be simulated and used as the fundamental parameter for scrutinising the evolution of the compressive strength. Particularly, a linear trend between the compressive strength and the degree of hydration and the maturity was figured out. [Copyright &y& Elsevier]

Abstract: CdS quantum dots (QDs) were uniformly deposited on mesoporous TiO2 films by high-pressure coating with liquid carbon dioxide (l-CO2) as a coating solvent. The size and coverage of CdS QDs over the TiO2 surface were controlled by the number of l-CO2 coating cycles applied at a fixed precursor concentration. The formation of CdS QDs on the mesoporous TiO2 film was confirmed by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HR-TEM). In addition, depth profiling investigation revealed that CdS QDs were uniformly deposited throughout the ∼15μm-thick mesoporous TiO2 film. The energy conversion efficiency of a CdS QD-sensitized solar cell (QDSSC) was observed to increase up to ∼1.33% under standard conditions (1.5AM, 100mWcm−2) with an increase in the number of coating cycles to six. Meanwhile, a further increase in the number of coating cycles to ten caused a decrease in the cell performance, which may be attributed to the hindrance of electrolyte infiltration into the mesoporous TiO2 electrode caused by the blocking of the pores with the coated CdS. The cell performance of the l-CO2-coated CdS-QDSSC is slightly higher than that of the l-CO2-coated CdS-QDSSC prepared by a conventional successive ionic layer absorption and reaction (SILAR) method with ethanol as the solvent (1.16%). [Copyright &y& Elsevier]

Donor lymphocyte infusion (DLI) results in complete cytogenetic remission (CCR) of relapsed chronic-phase chronic myeloid leukemia (CML-CP) after allogeneic stem cell transplantation (SCT) in up to 80% of patients. The main complication of DLI is graft-versus-host disease (GVHD). Decreasing the dose of DLI is associated with less GVHD but also with a longer interval between treatment and CCR. We postulated that combining α-interferon (α-IFN) with DLI would enable us to decrease the dose of DLI, thereby limiting GVHD, and at the same time to decrease the interval between DLI and CCR for patients with either a hematologic or cytogenetic relapse. For molecular relapses, we hypothesized that because of a lower tumor load, very low doses of DLI without α-IFN could be an effective treatment. Two groups of CML-CP patients treated with DLI at a very low dose of 0.5 to 1.0 × 107 mononuclear cells per kilogram, containing 2 to 6 × 106 CD3+ T cells per kilogram, were analyzed: 13 patients with a cytogenetic or a hematologic relapse after allogeneic SCT (group A) were treated with additional α-IFN therapy at a dose of 3 × 106 U 5 d/wk, and 8 patients with a molecular relapse were treated without α-IFN (group B). Twelve patients from group A reached a CCR. The median interval between DLI and CCR was 7 weeks (range, 5–18 weeks) for group A. All patients with a CCR reached complete donor chimerism at a median of 10 weeks after DLI (range, 6–121 weeks). Eleven patients reached molecular remission at a median of 15 weeks after DLI (range, 8–34 weeks). In group B, all patients reached a molecular remission at a median of 14 weeks (range, 12–29 weeks). Five patients from group A developed acute GVHD grade II to IV and extensive chronic GVHD. In group B, 1 patient developed acute GVHD grade II to IV and subsequently developed extensive chronic GVHD. With a median follow-up of 62 months, 10 patients in group A are alive and in continuous CCR. One patient had a molecular relapse, for which she successfully received additional DLI; another patient reached molecular remission only after 5 doses of DLI. Two patients from group A died of a gram-negative sepsis, and 1 died of an acute myocardial infection. In group B, all patients are alive and in molecular remission with a median follow-up of 20 months. One patient’s disease progressed but was successfully treated with DLI plus α-IFN. In conclusion, very-low-dose DLI in combination with α-IFN as treatment for cytogenetic or hematologic relapses of CML-CP after allogeneic SCT reduced the interval to obtain a CCR with acceptable GVHD when compared with the literature. Patients with a CCR also reached complete donor chimerism and complete molecular remissions. For patients with a molecular relapse, very-low-dose DLI alone is sufficient to induce molecular remissions in most patients and is associated with limited GVHD. [Copyright &y& Elsevier]

[Display omitted] • Stoichiometric model combines kinetics of pozzolanic metakaolin reactions with long-term transformation processes. • Primary pozzolanic metakaolin reactions are divided into C 4 AH 13 and C 2 ASH 8 contributions. • Activation energy for the main (C 2 ASH 8) pozzolanic metakaolin reaction is determined as 84 kJ/mol. • KOH accelerates reaction processes and reduces the activation energy of the pozzolanic metakaolin reaction to 69 kJ/mol. In the pursue of environmentally-friendly binders for the construction industry, metakaolin (MK) has emerged as promising material, with its hardening performance primarily driven by pozzolanic reactions. However, in systems containing MK and calcium hydroxide (CH), transformation reactions from metastable to stable phases, particularly in excessive CH conditions, can adversely affect material properties. To anticipate these processes, this study introduces a stoichiometry-based reaction modeling approach for pozzolanic MK reactions, encompassing both short-term kinetics and long-term transformation processes. The primary pozzolanic reactions of MK are briefly outlined, highlighting two sequential, partially overlapping reactions forming C 4 AH 13 and C 2 ASH 8. Short-term reaction kinetics are modeled using isothermal calorimetry measurements and deconvoluting the two reaction peaks. The model is in good agreement with experimental quantitative X–ray diffraction (qXRD), thermogravimetric analysis (TGA) and helium pycnometer (density, i.e. solid volume) results. Model limitations are discussed based on qualitative scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX) analysis. Leveraging the proposed model, the temperature dependency of pozzolanic MK reactions is analyzed, revealing an activation energy for the primary reaction of 84 kJ/mol. The model is intended to lay a foundation for designing innovative binder systems based on metakaolin, while paving the way for sustainable construction in the future. [ABSTRACT FROM AUTHOR]

[Display omitted] • The oxide composition designated as metakaolin to calcium hydroxide ratio determines C-A-S-H composition and time dependent (trans)formation reactions. • Stratlingite destabilizes in the presence of calcium hydroxide and transforms to more stable hydrogarnet phases. • Sulfate addition leads to rapid ettringite formation, that may transform to monosulfoaluminate and later to hydrogarnet. • Carbonates stabilize ettringite and favor formation of carboaluminates, which may decompose at later curing ages. • Enhanced pozzolanic metakaolin reactivity modeling for low-carbon binder design requires improved understanding of structure-related dissolution kinetics. Metakaolin (MK) has emerged as a highly promising supplementary material in low carbon binders for the construction industry. In wide range of applications, from lime to cement–based materials, its hardening performance relies on the pozzolanic reactivity between MK and calcium hydroxide (CH), resulting in the formation of diverse calcium-aluminate/silicate hydrates. The reaction sequence is affected by specific conditions dictated by the binder system employed in various applications. To advance the design of binders that reduce the carbon emissions, a systematical review on MK-based reactions is crucial. This review encompasses a broad range of MK/CH ratios and examines the effect of alkali hydroxides, carbonates and sulfates. The focus is on the formation and stability of pozzolanic hydrate phases over time and under different curing temperatures. Additionally, the review addresses the characteristics that directly affect MK reactivity, such as the (calcined) clay structure and the dissolution of the reactants. The systematic findings shed light on the hydrate phase assemblage, enabling a better understanding of the reaction mechanisms in complex systems, like MK cementitious blends. The results of this review serve as a valuable foundation for the development of novel "low-carbon" binder designs and compositions for both cementitious and lime-based binders. [ABSTRACT FROM AUTHOR]

In the quest for environmentally sustainable binders within the construction industry, metakaolin (MK) has emerged as a highly promising material. Its reactivity and hardening performance encompass a wide range of applications, spanning from lime to cement-based materials. This performance is primarily underpinned by the pozzolanic reaction with calcium hydroxide (CH), leading to the formation of various calcium aluminate silicate hydrates. The intricacies of the hydration kinetics and resultant reaction products hinge on several factors woven into the specifics of the binder type. This study investigates the influence of CH availability, explored through initially mixed MK/CH weight ratios of 0.33 and 1.0. Furthermore, the study examines the impact of introducing alkali hydroxides (KOH and NaOH) and/or sulfates (K 2 SO 4 and Na 2 SO 4) on the pozzolanic reactions. Short-term analysis employed inductively coupled plasma optical emission spectrometry (ICP-OES), and pH measurements for pore solution as well as isothermal calorimetry, and in-situ X-ray diffraction (XRD) on paste samples. Long-term investigations extended to 245 days at 40 °C, incorporating XRD, thermogravimetric (TGA) and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM/EDX). Results provide insights into the kinetics of phase assemblage and compositions of C-A-S-H gels, highlighting the transformation of metastable C 2 ASH 8 and C 4 AH 13 to stable Si-rich hydrogarnet phases, incorporating sulfate, under excess CH conditions. Higher MK/CH enriches Si/Ca, Al/Ca, enhancing C-A-S-H gels, while KOH addition further boosts Al/Ca ratios. [Display omitted] • High OH-/CH weight ratio (0.0307) promotes formation of alkaline aluminosilicates. • For higher MK/CH (1.0), sulfate addition slows pozzolanic reactions. • Excess CH transforms C 4 AH 13 and C 2 ASH 8 into hydrogarnet phases. • Sulfate localizes in aluminum-rich phases: AFt, AFm and hydrogarnet. • Higher MK/CH boosts Si/Ca, Al/Ca, enhancing CASH phases, while KOH increases Al/Ca. [ABSTRACT FROM AUTHOR]

This study focusses on the bond between asphalt and concrete. The bond is a decisive factor for the transfer of traffic loads. A lack of bond between the layers can quickly reduce the load-bearing behavior and thus lead to pavement failure. In the literature, the bond between asphalt pavements and concrete substrates is usually analyzed using mechanical test methods. With mechanical test methods, the effects of interlocking, glue adhesion and friction, which have an effect at the layer boundary, are not considered individually. Based on previous findings, the aim of this study is to carry out a precise analysis of the bonding at the layer interface between concrete and asphalt using bitumen emulsion by means of measurements with a high-resolution X-ray computer tomography (CT). To determine the effect of the surface texture of the substrate, the investigations were carried out on milled and smooth surface textures. In addition to the variation of the substrate profiles, the influence of the application quantity of the bitumen emulsions C40 B5-S and C60 BP4-S was analyzed by spraying quantities of 90 g/m² and 180 g/m² bitumen after breaking. A newly developed method was used to determine the effective degree of gluing at the layer boundary, which allowed the bonding efficiency to be determined. The results of the calculated degree of gluing for the individual variants show that the highest degree of gluing of 61.94% is achieved with the smooth texture variant and high application quantity of bitumen emulsion. The lowest degree of gluing of 17.01% was achieved with the milled texture variant without the application of bitumen emulsion. Overall, the results showed that the degree of gluing was increased for both surface textures by applying the bitumen emulsion. Compared to the smooth texture, the milled textures exhibit a lower degree of gluing for both bitumen quantities, which could be explained by the distribution of the bitumen emulsions on the substrate profiles. • In this study, the influence of bitumen emulsion at the layer bond between concrete and asphalt is analyzed using an imaging method. • A method for analyzing the degree of gluing is developed using CT images. • By developing FEM models from CT images, the contact surface between the individual materials at the layer boundary can be analyzed. • The investigations are carried out on different substrate profiles with different bitumen emulsions and application quantities. [ABSTRACT FROM AUTHOR]

• Humidity variations barely altered the mechanical properties of jute fiber. • Sisal fiber presented better adhesion under the proposed humidity levels. • Humidity effect on fibers can be assessed by their cellulose crystallinity index. • Sisal fiber presented better adhesion under the proposed humidity levels. The aim of this study is to determine how the mechanical behavior of natural fibers is affected by the environmental and internal relative humidity, especially on the fiber-matrix interface. For that, curauá, jute and sisal fibers were selected. The experimental program commenced determining the fibers' mechanical properties under tensile stresses, followed by X-ray diffraction measurement, thermogravimetric analysis, infra-red spectroscopy and dynamic water vapor sorption analysis, as well as a microscopic examination of fibers' rupture under tensile stresses. In addition, a 2D finite element analysis was carried out to assist the interpretation of the mechanical behavior of the pull-out tests. The results indicate that the absorption capacity of each fiber can be correlated to the amount of hemicellulose and cellulose cristalinity, and the fibers' swelling process was influenced by each microstructure and hemicellulose content. Results from the mechanical tests showed a strength enhancement when the fibers were submitted to low levels of relative humidity, while a drastic decrease in strength was observed along with higher levels. The development of finite element models helped understanding the geometric particularities of each fibers. From the results it is possible to state a unique correlation between each fiber and its respective moisture content. It is believed that this data can help the use of such fibers as reinforcement of cement-based systems and their durability under a wider range of relative humidity levels. [ABSTRACT FROM AUTHOR]

This study investigates the effects of carbon nanomaterials (CN), specifically nanohorns (CNHs) and nanotubes (MWCNTs), on geopolymer carbon nanocomposites (GCN). The research investigates 0.2%, 0.5% and 1.0% of CN and two curing conditions to understand their impact on the microstructure, morphology, and performance of GCN. Analytical techniques such as MIP, TGA-DTA, FTIR, Raman, SEM, and EDX are utilized to analyze the nanoadditives in alkali-silicate suspensions, fresh and hardened GCN. Ultrasonication is important for achieving better dispersion of MWCNTs, while CNH disperses more easily. Both MWCNTs and CNHs enhance flexural strength by up to around 58% and 44%, respectively, and reduce crack formation compared to the pristine geopolymer. Hydrothermal curing, despite leading to higher porosity, improves flexural strength due to increased geopolymerisation. The formation of a cross-polymerized network with oxo bonds and the release of water during the process contribute to increased strength and porosity, respectively. • Exploring carbon nanohorns (CNH) and multi-walled carbon nanotubes (MWCNT) as additives in geopolymers. • Highest flexural strength achieved with 0.5% MWCNTs at 60 °C curing. • Curing at 60 °C (vs. 20 °C) enhances the geopolymer network reticulation and CN-matrix interface. • Hydrothermal curing at 60 °C (vs. 20 °C) increases porosity but improves flexural strength. • Improvements through enhanced geopolymerisation and reduced bound water content. [ABSTRACT FROM AUTHOR]

This paper proposes a mesoscale approach for simulating moisture transport by capillary action in partly-saturated porous cementitious composites. The modeling approach explicitly accounts for moisture transport through a mesostructure composed of coarse aggregates, surrounding cementitious mortar and interfaces. These latter, namely interface transition zones (ITZs), allow to describe the interaction between aggregates and mortar, and may cause an alternative path for the internal moisture movements. Basic morphology effects of the ITZs are simulated using a ribbon approach. Random spatial distribution of cement particles are stacked in the meso-geometry. Aggregate particles are introduced as randomly perturbed polygons and the moisture transport is modeled as a diffusion problem and solved by means of the finite element method. The proposed constitutive models are based on a proper description of the permeability and pore size distribution which strongly affect the local moisture content. Numerical results at both macro- and mesoscale levels demonstrate the soundness and capability of the proposed approach. The integrated modeling results actually demonstrate the potential of the mesoscale approach and shows the role of the ITZs as an internal interconnected network. [ABSTRACT FROM AUTHOR]

Technologies based on phase change materials (PCMs) are promising solutions to reduce energy consumption in buildings and related greenhouse gas emissions. However, the performance of passive PCMs in buildings is highly dependent on the melting temperatures employed, as well as the climate where the building is located. Therefore, the present contribution describes an optimization-based method to design passive latent energy storage in buildings by using PCMs with different melting temperatures. To achieve this goal, a multi-objective genetic algorithm is coupled with the building energy models developed in EnergyPlus to find the best trade-off between annual heating and cooling loads. A small office is chosen as a case study to evaluate the energy performance of the buildings incorporating the proposed PCM approach. Three different PCM layers are added to the ceilings and the external and internal walls of the building, and their parametric models are developed in EnergyPlus to optimize the melting temperature and thickness of each PCM layer simultaneously. Moreover, a method to select climate-representative locations according to the ASHRAE 169-2020 climate classification and within the WMO Region VI (Europe) is proposed and applied, resulting in eight well-representative locations. An optimization-based design is carried out for each selected location and the performances of the optimized building designs are systematically compared to the ones of the baseline models. The optimization results achieved show that regardless of the climate zone analyzed, using several PCMs with different melting temperatures instead of a single one, is preferred. Moreover, the best performance of PCMs is attained in climate zones where both the heating and cooling loads are present. Thus, the highest saving regarding the annual total loads of 11.7% is achieved in zone 5A (Cold), while the lowest one of 2.3% is obtained in zone 1B (Very hot). [Display omitted] • Using PCMs with different melting temperatures in buildings is proposed. • A multi-objective optimization method to design the PCMs' properties is introduced. • Eight climate-representative locations in the WMO Region VI (Europe) are selected. • PCMs with different melting temperatures instead of a single one is preferred. • The best performance of PCMs is attained in climates where both loads are present. [ABSTRACT FROM AUTHOR]

Myelodysplastic syndromes (MDS) and chronic myelomonocytic leukemia (CMML) may be underreported in cancer registries such as the Netherlands Cancer Registry (NCR). Analysis of Dutch medical claims can complement NCR data on MDS and CMML. We analyzed data on 3681 MDS patients and 235 CMML patients aged ≥18 years with initial claims for MDS or CMML from the Dutch nationwide medical claims-based Diagnosis Treatment Combination Information System (DIS) between 2008 and 2010. Clinical information was available in the DIS. MDS and CMML were diagnosed without a bone marrow (BM) examination in almost half of the patients. The age-standardized incidence rate (ASR) per 100,000 in the cohort that underwent BM examinations compared with NCR data was 2.8 vs . 3.3 for MDS and 0.2 vs. 0.4 for CMML in 2008–2010. A conservative treatment approach was associated with increasing age and absence of BM examination in MDS ( p < 0.001 for both) and CMML patients ( p < 0.033 for both). In conclusion, the ASR of MDS in the cohort that underwent BM examinations was comparable with the NCR. The majority of elderly patients, either with or without BM examinations, received no therapy. Together, MDS and CMML may be misdiagnosed and inappropriately managed without a BM confirmation. [ABSTRACT FROM AUTHOR]

Subunit D of multisubunit RNA polymerase from many species of archaea is predicted to bind one to two iron-sulfur (Fe-S) clusters, the function of which is unknown. A survey of encoded subunit D in the genomes of sequenced archaea revealed six distinct groups based on the number of complete or partial [4Fe- 4S] cluster motifs within domain 3. Only subunitDfrom strictly anaerobic archaea, including all members of the Methanosarcinales, are predicted to bind two [4Fe-4S] clusters. We report herein the purification and characterization of Methanosarcina acetivorans subunit D in complex with subunit L. Expression of subunit D and subunit L in Escherichia coli resulted in the purification of a D-L heterodimer with only partial [4Fe-4S] cluster content. Reconstitution in vitro with iron and sulfide revealed that the M. acetivorans D-L heterodimer is capable of binding two redox-active [4Fe-4S] clusters. M. acetivorans subunit D deleted of domain 3 (DΔD3) was still capable of co-purifying with subunit L but was devoid of [4Fe-4S] clusters. Affinity purification of subunit D or subunit DΔD3 from M. acetivorans resulted in the co-purification of endogenous subunit L with each tagged subunit D. Overall, these results suggest that domain 3 of subunit D is required for [4Fe-4S] cluster binding, but the [4Fe-4S] clusters and domain 3 are not required for the formation of the D-L heterodimer. However, exposure of two [4Fe-4S] cluster-containing D-L heterodimer to oxygen resulted in loss of the [4Fe-4S] clusters and subsequent protein aggregation, indicating that the [4Fe-4S] clusters influence the stability of the D-L heterodimer and therefore have the potential to regulate the assembly and/or activity of RNA polymerase in an oxidant- dependent manner. [ABSTRACT FROM AUTHOR]

Abstract: Cephalic effects on appetite are mediated by vagal tone and altered gastrointestinal hormones. The objective of this study is to explore the relationship between appetite and levels of gastrointestinal hormones after smelling chocolate and after melt-and-swallow 30g chocolate (1.059oz, 85% cocoa, 12.5g of sugar per 100g product). Twelve female residents (BMI between 18 and 25kg/m2) all participated in two 60-minute study sessions. In the first session, all 12 women ate chocolate; for the second session, they were randomized either to smell chocolate (n =6) or to serve as a control (no eating or smelling; n =6). At the start of the sessions, levels of insulin, glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK), but not glucose, correlated with appetite scored on a visual analogue scale (VAS). In contrast, ghrelin levels correlated inversely with scored appetite. Chocolate eating and smelling both induced a similar appetite suppression with a disappearance of correlations between VAS scores and insulin, GLP-1 and CCK levels. However, while the correlation between VAS score and ghrelin disappeared completely after chocolate eating, it reversed after chocolate smelling, that is, olfactory stimulation with dark chocolate (85%) resulted in a satiation response that correlated inversely with ghrelin levels. [Copyright &y& Elsevier]

• Temperatures until 100 °C promote an improvement on tensile strength. • Temperature does not promote substantial modification on fiber cross-section. • Temperatures over 300 °C promote a breakage on microfibrils bonding. • Sisal fiber present a good adhesion to cement until 100 °C. This experimental investigation aims to study the influence of temperature on natural fibers mechanical performance and on its interface to cement based systems. Natural sisal fiber was used on this study. Temperatures of 20, 100, 150, 200, 250 and 300 °C were used as conditions for this research. The influence of temperature on this fiber was evaluated by scanning electron microscopy (SEM), x-ray diffraction patterns (XRD), thermogravimetric analysis (TGA). The mechanical properties were evaluated by tensile test. Pullout test were performed in order to evaluate bonding on cement-based matrix after exposition to higher temperatures. The results indicate a minor modification on sisal morphology after temperature exposition until 200 °C. At 250 °C a few microcracks were observed on fiber surface, indicating a debonding of sisal fibercells and microfibrils. Sisal mechanical behavior was improved until 150 °C. This may happen due the water evaporation and shrinkage, promoting a closed and densified fiber structure. Cement main component degradation was observed before degradation of the natural fiber (around 250 °C). Bonding to cement matrix decreased after 100 °C and was maintained stable until 150 °C, and resulted in pullout forces reduction of 75% in comparison to fiber tested at 20 °C. [ABSTRACT FROM AUTHOR]