Recycling of Contaminated Marine Sediment and Industrial By-Products through Combined Stabilization/Solidification and Granulation Treatment.

Stabilization/solidification (S/S) is becoming increasingly important, as it allows the remediation of contaminated sediments and their recovery into materials for civil engineering. This research proposes a cement-free cold granulation process for manufactured low-cost aggregates from marine sediments contaminated with organic compounds and metals. After the chemo-physical characterization of the study materials, two mix designs were prepared in a rotary plate granulator by adding two industrial by-products as geopolymer precursors, coal fly ash (CFA) and Blast Furnace Slag (BFS), but also alkaline activation solutions, water, and a fluidizer. The results indicated that sediments treated with mix 1 (i.e., with a higher percentage of water and fluidifier) represent the optimal solution in terms of metal leachability. The metal leachability was strictly influenced by aggregates' porosity, density, and microstructure. The technical performance (such as the aggregate impact value > 30%) suggested the use of granules as lightweight aggregates for pavement construction. The results indicated that cold granulation represents a sustainable solution to recycling contaminated marine sediments, CFA, and BFS into lightweight artificial aggregates.

Development of Geopolymer-Based Materials with Ceramic Waste for Artistic and Restoration Applications.

This contribution presents the preparation and characterization of new geopolymer-based mortars obtained from recycling waste deriving from the production process and the "end-of-life" of porcelain stoneware products. Structural, morphological, and mechanical studies carried out on different kinds of mortars prepared by using several types of by-products (i.e., pressed burnt and extruded ceramic waste, raw pressed and gypsum resulting from exhausted moulds) point out that these systems can be easily cast, also in complex shapes, and show a more consistent microstructure with respect to the geopolymer paste, with a reduced amount of microcracks. Moreover, the excellent adhesion of these materials to common substrates such as pottery and earthenware, even for an elevated concentration of filler, suggests their use in the field of technical-artistic value-added applications, such as restoration, conservation, and/or rehabilitation of historic monuments, or simply as materials for building revetments. For all these reasons, the proposed materials could represent valuable candidates to try to overcome some problems experienced in the cultural heritage sector concerning the selection of environmentally friendly materials that simultaneously meet art and design technical requirements.

The Improvement of Durability of Reinforced Concretes for Sustainable Structures: A Review on Different Approaches.

The topic of sustainability of reinforced concrete structures is strictly related with their durability in aggressive environments. In particular, at equal environmental impact, the higher the durability of construction materials, the higher the sustainability. The present review deals with the possible strategies aimed at producing sustainable and durable reinforced concrete structures in different environments. It focuses on the design methodologies as well as the use of unconventional corrosion-resistant reinforcements, alternative binders to Portland cement, and innovative or traditional solutions for reinforced concrete protection and prevention against rebars corrosion such as corrosion inhibitors, coatings, self-healing techniques, and waterproofing aggregates. Analysis of the scientific literature highlights that there is no preferential way for the production of "green" concrete but that the sustainability of the building materials can only be achieved by implementing simultaneous multiple strategies aimed at reducing environmental impact and improving both durability and performances.

Innovative Materials in Italy for Eco-Friendly and Sustainable Buildings.

In the last 20 years, there have been a series of seismic events in Italy that have caused serious damage to civil and building structures. This has led to a significant increase in the use of concrete for the reconstruction of new structures and the repair of existing structures damaged by earthquakes. At the same time, the concrete industry is responsible for the most significant environmental damage during the life cycle of the built environment. The environmental disadvantages characterizing the concrete industry are related to the constant growth of the exploitation of natural aggregates. Therefore, it is necessary to use alternative and innovative aggregates that provide good concrete performance and lower environmental impacts. In this study, a very promising route from an environmental point of view is given by the use of artificial aggregates from industrial waste as substitutes for natural aggregates. An innovative low cost and energy saving granulation process has been employed to produce lightweight aggregates using fly ash from the incineration of municipal solid waste and ground granulated blast furnace slag. The final aim of this research is to demonstrate the environmental sustainability of artificial aggregates, through a comparison of three different mixtures.

Fibre-Reinforced Geopolymer Concretes for Sensible Heat Thermal Energy Storage: Simulations and Environmental Impact.

Power plants based on solar energy are spreading to accomplish the incoming green energy transition. Besides, affordable high-temperature sensible heat thermal energy storage (SHTES) is required. In this work, the temperature distribution and thermal performance of novel solid media for SHTES are investigated by finite element method (FEM) modelling. A geopolymer, with/without fibre reinforcement, is simulated during a transient charging/discharging cycle. A life cycle assessment (LCA) analysis is also carried out to investigate the environmental impact and sustainability of the proposed materials, analysing the embodied energy, the transport, and the production process. A Multi-Criteria Decision Making (MCDM) with the Analytical Hierarchy Process (AHP) approach, taking into account thermal/environmental performance, is used to select the most suitable material. The results show that the localized reinforcement with fibres increases thermal storage performance, depending on the type of fibre, creating curvatures in the temperature profile and accelerating the charge/discharge. High-strength, high-conductivity carbon fibres performed well, and the simulation approach can be applied to any fibre arrangement/material. On the contrary, the benefit of the fibres is not straightforward according to the three different scenarios developed for the LCA and MCDM analyses, due to the high impact of the fibre production processes. More investigations are needed to balance and optimize the coupling of the fibre material and the solid medium to obtain high thermal performance and low impacts.

Comparing the use of preformed vs hand-made antibiotic spacer cement in two stages revision of hip periprosthetic infection.

BACKGROUND: The number of periprosthetic joint infections (PJI) is continuously increasing because of the increasing number of arthroprostheses performed every year. Two-stage revision, using antibiotic-loaded spacers, remains the gold standard for their treatment. The aim of our study is to compare the use of preformed vs hand-made spacers in hip arthroplasty infections evaluating infection eradication, bone loss and clinical/functional outcomes. METHODS: From January 2010 to December 2017 we performed a prospective nonrandomized study. We pooled 50 patients affected by infected hip joint replacements, and divided them in 2 groups, one receiving commercially preformed spacers and the other receiving hand-made spacers. The study endpoint was set at 12 months. Intra-operative and peri-operative complications, Harris Hip Score (HHS), Short Form 12 Health Survey, intra-operative and radiological evaluation of bone loss were collected. Data were analyzed using descriptive statistics, T-test and Fisher Exact test. RESULTS: We found a statistically significant differences (p < 0.05) between the two groups in favour of the VancogenX group for the following variables: surgical time, first and second stage intraoperative complication rates, infection eradication. Moreover, the preformed-spacers group had better results in the preservation of bone stock, even though the difference was not statistically significant (p > 0.05). CONCLUSION: Our results support the use of preformed antibiotic spacers, even though more studies are needed.

Hybrid Fly Ash-Based Geopolymeric Foams: Microstructural, Thermal and Mechanical Properties.

This research investigates the preparation and characterization of new organic-inorganic geopolymeric foams obtained by simultaneously reacting coal fly ash and an alkali silicate solution with polysiloxane oligomers. Foaming was realized in situ using Si0 as a blowing agent. Samples with density ranging from 0.3 to 0.7 g/cm3 that show good mechanical properties (with compressive strength up to ≈5 MPa for a density of 0.7 g/cm3) along with thermal performances (λ = 0.145 ± 0.001 W/m·K for the foamed sample with density 0.330 g/cm3) comparable to commercial lightweight materials used in the field of thermal insulation were prepared. Since these foams were obtained by valorizing waste byproducts, they could be considered as low environmental impact materials and, hence, with promising perspectives towards the circular economy.

The orthopaedic and traumatology scenario during Covid-19 outbreak in Italy: chronicles of a silent war.

BACKGROUND: From February 21, the day of hospitalisation in ICU of the first diagnosed case of Covid-19, the social situation and the hospitals' organisation throughout Italy dramatically changed. METHODS: The CIO (Club Italiano dell'Osteosintesi) is an Italian society devoted to the study of traumatology that counts members spread in public and private hospitals throughout the country. Fifteen members of the CIO, Chairmen of 15 Orthopaedic and Trauma Units of level 1 or 2 trauma centres in Italy, have been involved in the study. They were asked to record data about surgical, outpatients clinics and ER activity from the 23rd of February to the 4th of April 2020. The data collected were compared with the data of the same timeframe of the previous year (2019). RESULTS: Comparing with last year, overall outpatient activity reduced up to 75%, overall Emergency Room (ER) trauma consultations up to 71%, elective surgical activity reduced up to 100% within two weeks and trauma surgery excluding femoral neck fractures up to 50%. The surgical treatment of femoral neck fractures showed a stable reduction from 15 to 20% without a significant variation during the timeframe. CONCLUSIONS: Covid-19 outbreak showed a tremendous impact on all orthopaedic trauma activities throughout the country except for the surgical treatment of femoral neck fractures, which, although reduced, did not change in percentage within the analysed timeframe.

Entropy-Stabilized Oxides owning Fluorite Structure obtained by Hydrothermal Treatment.

Entropy-Stabilized Oxides (ESO) is a modern class of multicomponent advanced ceramic materials with attractive functional properties. Through a five-component oxide formulation, the configurational entropy is used to drive the phase stabilization over a reversible solid-state transformation from a multiphase to a single-phase state. In this paper, a new transition metal/rare earth entropy-stabilized oxide, with composition Ce0.2Zr0.2Y0.2Gd0.2La0.2O2-, was found after several investigations on alternative candidate systems. X-Ray Diffraction (XRD) analyses of calcined powders pointed out different behavior as a function of the composition and a single-phase fluorite structure was obtained after a specific thermal treatment at 1500 °C. Powders presented the absence of agglomeration, so that the sintered specimen exhibited sufficient densification with a small porosity, uniformly distributed in the sample.

Hybrid Geopolymeric Foams for the Removal of Metallic Ions from Aqueous Waste Solutions.

For the first time, hybrid organic-inorganic geopolymeric foams were successfully used as monolithic adsorbents for the removal of metallic ions pollutants from wastewaters. The foams were realized by the in situ foaming of a hybrid geopolymer obtained by a reaction of metakaolin and polysiloxane oligomers under strong alkaline conditions and then cured at room temperature. In this way, porous materials with densities ranging from 0.4 to 0.7 g/cm3 and showing good mechanical properties were produced. With the aim of producing self-standing monolithic adsorbents for the removal of metallic ions pollutants from wastewaters, these porous hybrid geopolymers were subjected to a washing pretreatment with ultrapure water, dried, and then used for absorption tests by dipping them into an aqueous solution with an initial concentration of 20 ppm of Pb2+, Cd2+, Cu2+, and Zn2+ ions. Preliminary results indicated that all the tested materials are effective in the adsorption of the tested metal ions and do not release the removed metal ions upon sinking in ultrapure water, even for a very long time. Interestingly, compressive strength tests performed before and after the washing treatments show that the foamed samples remain intact and maintain their physical-mechanical characteristics, suggesting that these kinds of materials are promising candidates for the production of self-standing, monolithic adsorbent substrates that can be easily collected when exhausted, which is a major advantage in comparison with the use of powdered adsorbents. Moreover, since these materials can be obtained by a simple and versatile experimental procedure, they could be easily shaped or directly foamed into precast molds to be used in packed beds as membranes.

Hybrid Geopolymers from Fly Ash and Polysiloxanes.

The preparation and characterization of innovative organic-inorganic hybrid geopolymers, obtained by valorizing coal fly ash generated from thermoelectric power plants, is reported for the first time. These hybrid materials are prepared by simultaneously reacting fly ash and dimethylsiloxane oligomers at 25 °C in a strongly alkaline environment. Despite their lower density, the obtained materials are characterized by highly improved mechanical properties when compared to the unmodified geopolymer obtained without the use of polysiloxanes, hence confirming the effectiveness of the applied synthetic strategy which specifically aims at obtaining hybrid materials with better mechanical properties in respect to conventional ones. This study is an example of the production of new materials by reusing and valorizing waste raw resources and by-products, thus representing a possible contribution towards the circular economy.

New Insights in the Hydrothermal Synthesis of Rare-Earth Carbonates.

The rare-earth carbonates represent a class of materials with great research interest owing to their intrinsic properties and because they can be used as template materials for the formation of other rare earth phases, particularly of rare-earth oxides. However, most of the literature is focused on the synthesis and characterization of hydroxycarbonates. Conversely, in the present study we have synthesized both rare-earth carbonates-with the chemical formula RE2(CO3)3·2-3H2O, in which RE represents a generic rare-earth element, and a tengerite-type structure with a peculiar morphology-and rare-earth hydroxycarbonates with the chemical formula RECO3OH, by hydrothermal treatment at low temperature (120 °C), using metal nitrates and ammonium carbonates as raw materials, and without using any additive or template. We found that the nature of the rare-earth used plays a crucial role in relation to the formed phases, as predicted by the contraction law of lanthanides. In particular, the hydrothermal synthesis of rare-earth carbonates with a tengerite-type structure was obtained for the lanthanides from neodymium to erbium. A possible explanation of the different behaviors of lighter and heavier rare-earths is given.

Binders alternative to Portland cement and waste management for sustainable construction-part 1.

This review presents "a state of the art" report on sustainability in construction materials. The authors propose different solutions to make the concrete industry more environmentally friendly in order to reduce greenhouse gases emissions and consumption of non-renewable resources. Part 1-the present paper-focuses on the use of binders alternative to Portland cement, including sulfoaluminate cements, alkali-activated materials, and geopolymers. Part 2 will be dedicated to traditional Portland-free binders and waste management and recycling in mortar and concrete production.

Binders alternative to Portland cement and waste management for sustainable construction - Part 2.

The paper represents the "state of the art" on sustainability in construction materials. In Part 1 of the paper, issues related to production, microstructures, chemical nature, engineering properties, and durability of mixtures based on binders alternative to Portland cement were presented. This second part of the paper concerns the use of traditional and innovative Portland-free lime-based mortars in the conservation of cultural heritage, and the recycling and management of wastes to reduce consumption of natural resources in the production of construction materials. The latter is one of the main concerns in terms of sustainability since nowadays more than 75% of wastes are disposed of in landfills.

Foot Loading and Gait Analysis Evaluation of Nonarticular Tibial Pilon Fracture: A Comparison of Three Surgical Techniques.

The aim of our study was to investigate which technique among hybrid external fixation, plate and screws, and intramedullary nailing produces better outcomes in foot loading when treating type 43.A1, 43.A2, and 43.A3 fractures, according to the AO classification. From November 2011 to December 2014, 34 patients, including 25 (73.5%) males and 9 (26.5%) females with an average age of 32.3 (range 16 to 67) years, with a type A tibia fracture were treated with intramedullary nailing, plate and screws, or hybrid external fixation. The patients were divided into 3 groups: 16 (47%) received hybrid external fixation, 10 (29.4%) received plate and screw fixation, and 8 (23.5%) received intramedullary nailing fixation. The follow-up protocol included clinical and radiologic evaluations performed at 15 days, 1 month, 3 months, 6 months, and 12 months after surgery. The selected outcome parameters for the 3 groups were as follows: visual analog scale for pain of the traumatized tibia, interval from surgery to weightbearing, average time required for fracture recovery, subjective and objective Ovadia-Beals scores, baropodometric examination at 12 months, walking recovery at 12 months, outcomes, and surgical complications. The endpoint assessment was set at 12 months. The results showed that incorrect reduction of a type A tibia fracture can lead to changes in the sagittal balance line for foot loading and pace training. In conclusion, these findings have shown that the experience of the surgeon in the reduction of the fracture and knowledge of the method of synthesis is essential.

Use of a Metal Organic Framework for the Adsorptive Removal of Gaseous HCl: A New Approach for a Challenging Task.

In this work, the potentialities of the amino-functionalized, chromium-based MIL-101 metal organic framework (NH2-MIL-101) as a high capacity, fully regenerable hydrogen chloride adsorbent have been proved by a thorough adsorption thermodynamics investigation. The chosen adsorbent showed high gaseous HCl adsorption capacities and, to the best of our knowledge, it is the first example of a totally regenerable substrate for this kind of adsorbate, as evidenced by both experimental and modeling results. This paves the way to the implementation of greener, more energetically efficient pressure/temperature swing adsorption processes to purify biogas feeds for high-temperature fuel cells.

Life cycle assessment of recycled concretes: A case study in southern Italy.

Concrete industry is responsible of the most significant contribution to the global warming due to the large amount of substances with environmental impacts produced during its entire life cycle (production process, construction, maintenance, dismantlement, and scrapping). The most important issue characterizing the concrete industry is related to the constant growth of consumption of natural aggregates. The purpose of the present research is to apply the standard protocol of life cycle assessment to 3 different concrete mixtures composed by wastes from construction and demolition (C&D), marble sludge and cement kiln dust (CDK) in order to compare the environmental and energy impacts. The main purpose is to analyze the potentials (capabilities/benefits) of recycled aggregate concrete. The proposed model analyses 37 recovery possible scenarios. The results were analyzed with the software SimaPro© and with the life cycle impact assessment method Eco Indicator 99. The results show how it is possible to decide for the optimal solution in order to reduce emissions and impacts due to the concrete production.

Characterization of Early Age Curing and Shrinkage of Metakaolin-Based Inorganic Binders with Different Rheological Behavior by Fiber Bragg Grating Sensors.

This paper reports results related to early age temperature and shrinkage measurements by means fiber Bragg gratings (FBGs), which were embedded in geopolymer matrices. The sensors were properly packaged in order to discriminate between different shrinkage behavior and temperature development. Geopolymer systems based on metakaolin were investigated, which dealt with different commercial aluminosilicate precursors and siliceous filler contents. The proposed measuring system will allow us to control, in a very accurate way, the early age phases of the binding systems made by metakaolin geopolymer. A series of experiments were conducted on different compositions; moreover, rheological issues related to the proposed experimental method were also assessed.

Use of Common Inflammatory Markers in the Long-Term Screening of Total Hip Arthroprosthesis Infections: Our Experience.

Orthopedic implants have become essential components of modern medicine. The risk of infection of total hip arthroplasty (THA) is 1.5%-2%. Are the C-reactive protein (CRP), the erythrocyte sedimentation rate (ESR), and procalcitonin (PCT) good markers for THA infection screenings? From February 2009 to December 2012 at our Department of Orthopedics and Traumatology, 1248 patients were treated with THA. No prosthesis was cemented. All patients received antibiotic prophylaxis. All patients were discharged approximately 7.4 days after surgery with this clinical and radiographic follow-up program at 15 days and 1, 3, 6, 12, 24, and 36 months after surgery. Blood samples to determine ESR, CRP, and PCT values were taken at 1 hour before surgery and 15 days and 1, 3, 6, 12, 24, and 36 months after surgery. During follow-ups there were 22 cases of THA infections; according the Widmer classification, infections are hematogenous ones in 16 cases, late chronic ones in 5 cases, and early postoperative ones in 1 case. In all cases the three markers were considered positive; in 6 cases there were no radiological signs of septic loosening. ESR, CRP, and PCT proved to have a greater diagnostic accuracy than X-rays in predicting late chronic and early postoperative infections. These markers are valuable support for the surgeon in monitoring the prosthetic implant lifespan.

Effect of the mineralizer solution in the hydrothermal synthesis of gadolinium-doped (10% mol Gd) ceria nanopowders.

BACKGROUND: Gadolinium-doped ceria is an attractive electrolyte material for potential application in solid oxide fuel cells (SOFCs) operating at intermediate temperatures typically with 10%-20% substitution of Ce+4 by Gd+3. In particular, 10% gadolinium-doped ceria seems to have the highest values of conductivities among the other dopant compositions. METHODS: Nanosized powders of gadolinium-doped ceria were prepared by hydrothermal treatment using coprecipitate as a precursor and in the presence of 3 different mineralizer solutions. The powders obtained were characterized by X-ray diffraction analysis, scanning electron microscopy, transmission electron microscopy and thermal analysis, while the electrical behavior of the corresponding pellets were ascertained by AC impedance spectroscopy. RESULTS: Nanocrystalline gadolinium-doped ceria powders with fluorite cubic crystal structure were obtained by hydrothermal treatment. Independent of the mineralizer used, these powders were able to produce very dense ceramics, especially when selecting an optimized sintering cycle. In contrast, the electrical behavior of the samples was influenced by the mineralizer solution, and the samples synthesized in the neutral and alkaline solutions showed higher values of electrical conductivity, in the range of temperatures of interest. CONCLUSIONS: By the coprecipitation method, it has been possible to synthesize nanosized gadolinium-doped cerium oxide in a fluorite structure, stable in a wide range of temperatures. Hydrothermal treatment directly on the as-synthesized coprecipitates, without any drying step, had a very positive effect on the powders, which can be sintered with a high degree of densification, especially with an optimized sintering cycle. Furthermore, the electrical behavior of these samples was very interesting, especially for the samples synthesized using neutral mineralizer solution and basic mineralizer solution.