Characterization of a Novel CaCO3-Forming Alkali-Tolerant Rhodococcus erythreus S26 as a Filling Agent for Repairing Concrete Cracks

Biomineralization, a well-known natural phenomenon associated with various microbial species, is being studied to protect and strengthen building materials such as concrete. We characterized Rhodococcus erythreus S26, a novel urease-producing bacterium exhibiting CaCO3-forming activity, and investigated its ability in repairing concrete cracks for the development of environment-friendly sealants. Strain S26 grown in solid medium formed spherical and polygonal CaCO3 crystals. The S26 cells grown in a urea-containing liquid medium caused culture fluid alkalinization and increased CaCO3 levels, indicating that ureolysis was responsible for CaCO3 formation. Urease activity and CaCO3 formation increased with incubation time, reaching a maximum of 2054 U/min/mL and 3.83 g/L, respectively, at day four. The maximum CaCO3 formation was achieved when calcium lactate was used as the calcium source, followed by calcium gluconate. Although cell growth was observed after the induction period at pH 10.5, strain S26 could grow at a wide range of pH 4–10.5, showing its high alkali tolerance. FESEM showed rhombohedral crystals of 20–60 µm in size. EDX analysis indicated the presence of calcium, carbon, and oxygen in the crystals. XRD confirmed these crystals as CaCO3 containing calcite and vaterite. Furthermore, R. erythreus S26 successfully repaired the artificially induced large cracks of 0.4–0.6 mm width.

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On the characterization of pore size distribution of building materials

Journal of Building Physics ◽

10.1177/1744259117698515 ◽

2017 ◽

Vol 41 (3) ◽

pp. 247-263 ◽

Cited By ~ 1

Author(s):

LF Dutra ◽

N Mendes ◽

PC Philippi

Keyword(s):

Relative Humidity ◽

Pore Size Distribution ◽

Pore Size ◽

Size Distribution ◽

Building Materials ◽

Mercury Porosimetry ◽

Energy Performance ◽

Volume Distribution ◽

Wide Range

Moisture affects significantly the energy performance of air conditioning systems, the durability of materials, and the health of occupants. One way of reducing those effects, without increasing the energy costs, is by means of using porous material ability of absorbing and releasing moisture from/to the adjacent environment, which attenuates the indoor relative humidity variation. This natural ability is intrinsically related to the porous microstructure. Therefore, the characterization of the pore space is an important research theme in the building physics area. This article aims to present a method for obtaining the pore size distribution based on adsorption isotherms and mercury porosimetry data. First, the theoretical formulation based on the Gibbs free energy for a two-phase (liquid–vapor) system, using the De Boer and Zwikker model, is presented, allowing the calculation of the critical adsorbed thickness for pore filling, critical radius, adsorbed moisture content, capillary condensation content, available surface for adsorption, and the distribution of micropores for a wide range of radius. The adsorption isotherm curve is estimated for high relative humidity values through mercury porosimetry, along with the adsorption curve obtained from the experiment. The pore volume distribution calculated by this method can be used to estimate transport coefficients for liquid and vapor phases.

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A Review on Synthesis, Characterization and Applications of Copper Nanoparticles Using Green Method

NANO ◽

10.1142/s1793292017500436 ◽

2017 ◽

Vol 12 (04) ◽

pp. 1750043 ◽

Cited By ~ 24

Author(s):

Muhammad Rafique ◽

Ahson J. Shaikh ◽

Reena Rasheed ◽

Muhammad Bilal Tahir ◽

Hafiz Faiq Bakhat ◽

...

Keyword(s):

Copper Nanoparticles ◽

Inorganic Material ◽

Synthesis Method ◽

Green Method ◽

Environment Friendly ◽

Modern Age ◽

Wide Range ◽

Material Sciences ◽

Conventional Methods

To address accosts of this modern age, the synthesis of metal nanoparticles is more important than ever. Copper has been recognized as a nontoxic, safe inorganic material, cheaper antibacterial/antifungal agent, and has high potential in a wide range of biological, catalytic and sensors applications more particularly in the form of nanoparticles. This resulted in the development of numerous methods for the synthesis of copper nanoparticles. As conventional methods like chemical and physical methods have several limitations so there is need to an alternate method. Due to nontoxic and eco-friendly nature, it has recently been shifted toward green synthesis of copper nanoparticles over conventional methods. Additionally, characterization of the synthesized nanoparticles is essential for their use in various applications. This review gives an overview of environment friendly synthesis method of copper nanoparticles and their applications on the basis of their potential selectivity and preferences in a number of fields like material sciences and biomedicine.

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Polymer Chemistry

10.1093/oso/9780198503095.001.0001 ◽

2004 ◽

Keyword(s):

Conducting Polymers ◽

Liquid Crystalline ◽

Polymer Chemistry ◽

Chain Growth ◽

Crystalline Polymers ◽

Wide Range ◽

Cyclic Oligomers ◽

Step Growth

Polymer Chemistry: A Practical Approach in Chemistry has been designed for both chemists working in and new to the area of polymer synthesis. It contains detailed instructions for preparation of a wide-range of polymers by a wide variety of different techniques, and describes how this synthetic methodology can be applied to the development of new materials. It includes details of well-established techniques, e.g. chain-growth or step-growth processes together with more up-to-date examples using methods such as atom-transfer radical polymerization. Less well-known procedures are also included, e.g. electrochemical synthesis of conducting polymers and the preparation of liquid crystalline elastomers with highly ordered structures. Other topics covered include general polymerization methodology, controlled/"living" polymerization methods, the formation of cyclic oligomers during step-growth polymerization, the synthesis of conducting polymers based on heterocyclic compounds, dendrimers, the preparation of imprinted polymers and liquid crystalline polymers. The main bulk of the text is preceded by an introductory chapter detailing some of the techniques available to the scientist for the characterization of polymers, both in terms of their chemical composition and in terms of their properties as materials. The book is intended not only for the specialist in polymer chemistry, but also for the organic chemist with little experience who requires a practical introduction to the field.

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Recycling and Reuse in the Roman Economy

10.1093/oso/9780198860846.001.0001 ◽

2020 ◽

Keyword(s):

Building Materials ◽

Computational Modelling ◽

Late Antique ◽

Roman Economy ◽

Wide Range ◽

The Status ◽

Recent Developments ◽

Methodological Approaches ◽

First Time ◽

Site Types

The recycling and reuse of materials and objects were extensive in the past, but have rarely been embedded into models of the economy; even more rarely has any attempt been made to assess the scale of these practices. Recent developments, including the use of large datasets, computational modelling, and high-resolution analytical chemistry, are increasingly offering the means to reconstruct recycling and reuse, and even to approach the thorny matter of quantification. Growing scholarly interest in the topic has also led to an increasing recognition of these practices from those employing more traditional methodological approaches, which are sometimes coupled with innovative archaeological theory. Thanks to these efforts, it has been possible for the first time in this volume to draw together archaeological case studies on the recycling and reuse of a wide range of materials, from papyri and textiles, to amphorae, metals and glass, building materials and statuary. Recycling and reuse occur at a range of site types, and often in contexts which cross-cut material categories, or move from one object category to another. The volume focuses principally on the Roman Imperial and late antique world, over a broad geographical span ranging from Britain to North Africa and the East Mediterranean. Last, but not least, the volume is unique in focusing upon these activities as a part of the status quo, and not just as a response to crisis.

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Thermal Characterization of Recycled Materials for Building Insulation

Energies ◽

10.3390/en14123564 ◽

2021 ◽

Vol 14 (12) ◽

pp. 3564

Author(s):

Arnas Majumder ◽

Laura Canale ◽

Costantino Carlo Mastino ◽

Antonio Pacitto ◽

Andrea Frattolillo ◽

...

Keyword(s):

Environmental Impact ◽

Environmental Sustainability ◽

Building Materials ◽

Raw Materials ◽

Natural Fibers ◽

Thermal Characterization ◽

Recycled Materials ◽

Building Insulation ◽

Operational Phase

The building sector is known to have a significant environmental impact, considering that it is the largest contributor to global greenhouse gas emissions of around 36% and is also responsible for about 40% of global energy consumption. Of this, about 50% takes place during the building operational phase, while around 10–20% is consumed in materials manufacturing, transport and building construction, maintenance, and demolition. Increasing the necessity of reducing the environmental impact of buildings has led to enhancing not only the thermal performances of building materials, but also the environmental sustainability of their production chains and waste prevention. As a consequence, novel thermo-insulating building materials or products have been developed by using both locally produced natural and waste/recycled materials that are able to provide good thermal performances while also having a lower environmental impact. In this context, the aim of this work is to provide a detailed analysis for the thermal characterization of recycled materials for building insulation. To this end, the thermal behavior of different materials representing industrial residual or wastes collected or recycled using Sardinian zero-km locally available raw materials was investigated, namely: (1) plasters with recycled materials; (2) plasters with natural fibers; and (3) building insulation materials with natural fibers. Results indicate that the investigated materials were able to improve not only the energy performances but also the environmental comfort in both new and in existing buildings. In particular, plasters and mortars with recycled materials and with natural fibers showed, respectively, values of thermal conductivity (at 20 °C) lower than 0.475 and 0.272 W/(m⋅K), while that of building materials with natural fibers was always lower than 0.162 W/(m⋅K) with lower values for compounds with recycled materials (0.107 W/(m⋅K)). Further developments are underway to analyze the mechanical properties of these materials.

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Organelle Genetics in Plants

International Journal of Molecular Sciences ◽

10.3390/ijms22042104 ◽

2021 ◽

Vol 22 (4) ◽

pp. 2104

Author(s):

Pedro Robles ◽

Víctor Quesada

Keyword(s):

Rna Editing ◽

Posttranscriptional Regulation ◽

Genome Engineering ◽

Plant Mitochondria ◽

Plastid Dna ◽

Chloroplast Genomes ◽

Wide Range ◽

Organelle Genetics ◽

Selection Of

Eleven published articles (4 reviews, 7 research papers) are collected in the Special Issue entitled “Organelle Genetics in Plants.” This selection of papers covers a wide range of topics related to chloroplasts and plant mitochondria research: (i) organellar gene expression (OGE) and, more specifically, chloroplast RNA editing in soybean, mitochondria RNA editing, and intron splicing in soybean during nodulation, as well as the study of the roles of transcriptional and posttranscriptional regulation of OGE in plant adaptation to environmental stress; (ii) analysis of the nuclear integrants of mitochondrial DNA (NUMTs) or plastid DNA (NUPTs); (iii) sequencing and characterization of mitochondrial and chloroplast genomes; (iv) recent advances in plastid genome engineering. Here we summarize the main findings of these works, which represent the latest research on the genetics, genomics, and biotechnology of chloroplasts and mitochondria.

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Characterization of swelling behavior of carbon nano-filler modified polydimethylsiloxane composites

Journal of Elastomers & Plastics ◽

10.1177/00952443211006156 ◽

2021 ◽

pp. 009524432110061

Author(s):

Bo Yang ◽

Balakrishnan Nagarajan ◽

Pierre Mertiny

Keyword(s):

Digital Image Analysis ◽

Swelling Behavior ◽

Optical Measurements ◽

Natural Phenomenon ◽

Cross Linking ◽

Dimensional Changes ◽

Experimental Findings ◽

Carbon Based

Polymers may absorb fluids from their surroundings via the natural phenomenon of swelling. Dimensional changes due to swelling can affect the function of polymer components, such as in the case of seals, microfluidic components and electromechanical sensors. An understanding of the swelling behavior of polymers and means for controlling it can improve the design of polymer components, for example, for the previously mentioned applications. Carbon-based fillers have risen in popularity to be used for the property enhancement of resulting polymer composites. The present investigation focuses on the effects of three carbon-based nano-fillers (graphene nano-platelets, carbon black, and graphene nano-scrolls) on the dimensional changes of polydimethylsiloxane composites due to swelling when immersed in certain organic solvents. For this study, a facile and expedient methodology comprised of optical measurements in conjunction with digital image analysis was developed as the primary experimental technique to quantify swelling dimensional changes of the prepared composites. Other experimental techniques assessed polymer cross-linking densities and elastic mechanical properties of the various materials. The study revealed that the addition of certain carbon-based nano-fillers increased the overall swelling of the composites. The extent of swelling further depended on the organic solvent in which the composites were immersed in. Experimental findings are contrasted with published models for swelling prediction, and the role of filler morphology on swelling behavior is discussed.

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6-Axis Stress Tensor Sensor Using Multifaceted Silicon Piezoresistors

Micromachines ◽

10.3390/mi12030279 ◽

2021 ◽

Vol 12 (3) ◽

pp. 279

Author(s):

Kentaro Noda ◽

Jian Sun ◽

Isao Shimoyama

Keyword(s):

Stress Tensor ◽

Elastic Body ◽

Building Materials ◽

Sensor Response ◽

Stress Change ◽

Sensor Chip ◽

Naked Eye ◽

Highly Sensitive ◽

Wide Range

A tensor sensor can be used to measure deformations in an object that are not visible to the naked eye by detecting the stress change inside the object. Such sensors have a wide range of application. For example, a tensor sensor can be used to predict fatigue in building materials by detecting the stress change inside the materials, thereby preventing accidents. In this case, a sensor of small size that can measure all nine components of the tensor is required. In this study, a tensor sensor consisting of highly sensitive piezoresistive beams and a cantilever to measure all of the tensor components was developed using MEMS processes. The designed sensor had dimensions of 2.0 mm by 2.0 mm by 0.3 mm (length by width by thickness). The sensor chip was embedded in a 15 mm3 cubic polydimethylsiloxane (PDMS) (polydimethylsiloxane) elastic body and then calibrated to verify the sensor response to the stress tensor. We demonstrated that 6-axis normal and shear Cauchy stresses with 5 kPa in magnitudes can be measured by using the fabricated sensor.

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Isolation and Characterization of Strain Exiguobacterium sp. KRL4, a Producer of Bioactive Secondary Metabolites from a Tibetan Glacier

Microorganisms ◽

10.3390/microorganisms9050890 ◽

2021 ◽

Vol 9 (5) ◽

pp. 890

Author(s):

Pietro Tedesco ◽

Fortunato Palma Esposito ◽

Antonio Masino ◽

Giovanni Andrea Vitale ◽

Emiliana Tortorella ◽

...

Keyword(s):

Phenotypic Analysis ◽

Biological Assays ◽

C Elegans ◽

Isolation And Characterization ◽

Wide Range ◽

Protein Encoding ◽

Nematocidal Activity ◽

Extremophilic Microorganisms ◽

Unique Source

Extremophilic microorganisms represent a unique source of novel natural products. Among them, cold adapted bacteria and particularly alpine microorganisms are still underexplored. Here, we describe the isolation and characterization of a novel Gram-positive, aerobic rod-shaped alpine bacterium (KRL4), isolated from sediments from the Karuola glacier in Tibet, China. Complete phenotypic analysis was performed revealing the great adaptability of the strain to a wide range of temperatures (5–40 °C), pHs (5.5–8.5), and salinities (0–15% w/v NaCl). Genome sequencing identified KRL4 as a member of the placeholder genus Exiguobacterium_A and annotation revealed that only half of the protein-encoding genes (1522 of 3079) could be assigned a putative function. An analysis of the secondary metabolite clusters revealed the presence of two uncharacterized phytoene synthase containing pathways and a novel siderophore pathway. Biological assays confirmed that the strain produces molecules with antioxidant and siderophore activities. Furthermore, intracellular extracts showed nematocidal activity towards C. elegans, suggesting that strain KRL4 is a source of anthelmintic compounds.

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Towards Reduced CNNs for De-Noising Phase Images Corrupted with Speckle Noise

Photonics ◽

10.3390/photonics8070255 ◽

2021 ◽

Vol 8 (7) ◽

pp. 255

Author(s):

Marie Tahon ◽

Silvio Montresor ◽

Pascal Picart

Keyword(s):

Phase Error ◽

Speckle Noise ◽

Experimental Conditions ◽

Benchmark Data ◽

Wide Range ◽

Phase Images ◽

Different Depths ◽

Phase Data ◽

Do So

Digital holography is a very efficient technique for 3D imaging and the characterization of changes at the surfaces of objects. However, during the process of holographic interferometry, the reconstructed phase images suffer from speckle noise. In this paper, de-noising is addressed with phase images corrupted with speckle noise. To do so, DnCNN residual networks with different depths were built and trained with various holographic noisy phase data. The possibility of using a network pre-trained on natural images with Gaussian noise is also investigated. All models are evaluated in terms of phase error with HOLODEEP benchmark data and with three unseen images corresponding to different experimental conditions. The best results are obtained using a network with only four convolutional blocks and trained with a wide range of noisy phase patterns.

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