Cracow University of Technology

The aim of this review article on recent developments of mechanochemistry (nowadays established as a part of chemistry) is to provide a comprehensive overview of advances achieved in the field of atomistic processes, phase transformations, simple and multicomponent nanosystems and peculiarities of mechanochemical reactions. Industrial aspects with successful penetration into fields like materials engineering, heterogeneous catalysis and extractive metallurgy are also reviewed. The hallmarks of mechanochemistry include influencing reactivity of solids by the presence of solid-state defects, interphases and relaxation phenomena, enabling processes to take place under non-equilibrium conditions, creating a well-crystallized core of nanoparticles with disordered near-surface shell regions and performing simple dry time-convenient one-step syntheses. Underlying these hallmarks are technological consequences like preparing new nanomaterials with the desired properties or producing these materials in a reproducible way with high yield and under simple and easy operating conditions. The last but not least hallmark is enabling work under environmentally friendly and essentially waste-free conditions (822 references).

Kernel density estimation is a technique for estimation of probability density function that is a must-have enabling the user to better analyse the studied probability distribution than when using a traditional histogram. Unlike the histogram, the kernel technique produces smooth estimate of the pdf, uses all sample points' locations and more convincingly suggest multimodality. In its two-dimensional applications, kernel estimation is even better as the 2D histogram requires additionally to define the orientation of 2D bins. Two concepts play fundamental role in kernel estimation: kernel function shape and coefficient of smoothness, of which the latter is crucial to the method. Several real-life examples, both for univariate and bivariate applications, are shown.

Due to its three hydroxyl groups, glycerol is a potential starting material for various high value fine chemicals such as dihydroxyacetone, tartronic acid and mesoxalic acid. The corresponding oxidation reactions are catalysed by various metals such as palladium, platinum, bismuth or gold. Nevertheless, the selectivity not only depends on the type of the active phase, but is also influenced by numerous parameters such as the metal particles size, the pore size of the support and the pH of the reaction medium. This review not only describes the recent developments in the field of research for new catalysts but also spotlights the role of the reaction conditions as well as the possible transport limitations in this tri-phasic system. Furthermore, an economical analysis of some processes is given, which shows that this is realistic to envision sustainable production of, e.g., dihydroxyacetone.

The paper presents the state-of-the-art concerning the current achievements in the field of 3D printing of buildings and building components. The 3D printing technologies, comparing to traditional techniques of constructing the buildings, could be considered as environmental friendly derivative giving almost unlimited possibilities for geometric complexity realizations. Two kinds of technologies were described in this paper with pointing to Contour Crafting as a promising technique that may be able to revolutionize construction industry in near future. Numerous advantages of this technology, such as reduction of the costs and time, minimizing the pollution of environment and decrease of injuries and fatalities on construction sites could be cited. Despite many advantages and hopes, some concerns are summarized in the conclusions, as the technology still has many limitations. A brief description of few examples of pioneering usage of 3D printing in construction industry are presented (Canal House in Amsterdam, WinSun company and printing application for building carried out by Skanska company). Creating a model that will be appropriate for 3D printers is possible in many different modelling programs. One of the most popular formats for sharing such models is STL format. In the paper sample models crated in Autodesk Inventor are shown, but also other tools suitable for preparing models for 3D printing are briefly discussed.

Abstract This paper presents an overview of the research carried out by a European consortium with the aim to develop and test new and improved ways to realise dye‐sensitized solar cells (DSC) with enhanced efficiencies and stabilities. Several new areas have been explored in the field of new concepts and materials, fabrication protocols for TiO 2 and scatterlayers, metal oxide blocking layers, strategies for co‐sensitization and low temperature processes of platinum deposition. Fundamental understanding of the working principles has been gained by means of electrical and optical modelling and advanced characterization techniques. Cost analyses have been made to demonstrate the potential of DSC as a low cost thin film PV technology. The combined efforts have led to maximum non‐certified power conversion efficiencies under full sunlight of 11% for areas <0ċ2 cm 2 and 10ċ1% for a cell with an active area of 1ċ3 cm 2 . Lifetime studies revealed negligible device degradation after 1000 hrs of accelerated tests under thermal stress at 80°C in the dark and visible light soaking at 60°C. An outlook summarizing future directions in the research and large‐scale production of DSC is presented. Copyright © 2006 John Wiley & Sons, Ltd.

Severe plastic deformation (SPD) is effective in producing bulk ultrafine-grained and nanostructured materials with large densities of lattice defects. This field, also known as NanoSPD, experienced a significant progress within the past two decades. Beside classic SPD methods such as high-pressure torsion, equal-channel angular pressing, accumulative roll-bonding, twist extrusion, and multi-directional forging, various continuous techniques were introduced to produce upscaled samples. Moreover, numerous alloys, glasses, semiconductors, ceramics, polymers, and their composites were processed. The SPD methods were used to synthesize new materials or to stabilize metastable phases with advanced mechanical and functional properties. High strength combined with high ductility, low/room-temperature superplasticity, creep resistance, hydrogen storage, photocatalytic hydrogen production, photocatalytic CO2 conversion, superconductivity, thermoelectric performance, radiation resistance, corrosion resistance, and biocompatibility are some highlighted properties of SPD-processed materials. This article reviews recent advances in the NanoSPD field and provides a brief history regarding its progress from the ancient times to modernity. Abbreviations: ARB: Accumulative Roll-Bonding; BCC: Body-Centered Cubic; DAC: Diamond Anvil Cell; EBSD: Electron Backscatter Diffraction; ECAP: Equal-Channel Angular Pressing (Extrusion); FCC: Face-Centered Cubic; FEM: Finite Element Method; FSP: Friction Stir Processing; HCP: Hexagonal Close-Packed; HPT: High-Pressure Torsion; HPTT: High-Pressure Tube Twisting; MDF: Multi-Directional (-Axial) Forging; NanoSPD: Nanomaterials by Severe Plastic Deformation; SDAC: Shear (Rotational) Diamond Anvil Cell; SEM: Scanning Electron Microscopy; SMAT: Surface Mechanical Attrition Treatment; SPD: Severe Plastic Deformation; TE: Twist Extrusion; TEM: Transmission Electron Microscopy; UFG: Ultrafine Grained. © 2022 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.

The Kjeldahl method was introduced in 1883 and consists of three main steps: sample digestion, distillation, and ammonia determination (titration being the primary method). The Kjeldahl method uses sulfuric acid, a variety of catalysts, and salts to convert organically bound nitrogen in samples to ammonium with its subsequent measurement (Sáez-Plaza et al., 2013). Today, this method is universally accepted and used in tens of thousands of laboratories throughout the world for nitrogen analysis in a wide variety of materials, such as foods, beverages, agricultural products, environmental samples, chemicals, biochemicals, and pharmaceuticals. However, successful analysis requires proper sampling and sample handling, which depend on the type of material. The Kjeldahl method has been validated and standardized for total (crude) protein estimation for a wide variety of food matrices, indirectly determined by their nitrogen content, and is the reference method adopted by many international organizations. The Kjeldahl procedure has several variants, based mainly on a sample size and apparatus required. A number of rapid and accurate instrumental methods have been gradually introduced that have some advantages compared to older techniques, if a large number of samples are to be run. Thus, extracted nitrogen from Kjeldahl can be determined by several other methods, i.e., spectrophotometric, potentiometric with ion selective electrode, FIA, ion chromatographic, and chemiluminescent methods. Quality control is essential for accurate and precise measurements of nitrogen by the Kjeldahl method. The importance of quality control in Kjeldahl analysis is stressed in this review. Despite some negative factors (i.e., it is hazardous, lengthy, and labor intensive), the Kjeldahl method and its variants with instrumental finish remain as accurate and reliable methods.

Abstract The paper presents the impact of high temperature on cement concrete. The presented data have been selected both from the author’s most recent research and the published literature in order to provide a brief outline of the subject. The effect of a high temperature on concrete covers changes taking place in cement paste, aggregates, as well as the interaction of these two constituents, that result in changes of mechanical and physical characteristics of concrete. This paper presents the effects of a high temperature on selected physical properties of concrete, including colour change, thermal strain, thermal strains under load, and transient thermal strains. In addition, changes to mechanical properties are discussed: stress-strain relationship, compressive strength, and modulus of elasticity. Moreover, the phenomenon of explosive spalling and the main factors that affect its extent are analysed in light of the most recent research

We report the beam energy (sqrt[sNN]=7.7-200 GeV) and collision centrality dependence of the mean (M), standard deviation (σ), skewness (S), and kurtosis (κ) of the net-proton multiplicity distributions in Au+Au collisions. The measurements are carried out by the STAR experiment at midrapidity (|y|<0.5) and within the transverse momentum range 0.4<pT<0.8 GeV/c in the first phase of the Beam Energy Scan program at the Relativistic Heavy Ion Collider. These measurements are important for understanding the quantum chromodynamic phase diagram. The products of the moments, Sσ and κσ2, are sensitive to the correlation length of the hot and dense medium created in the collisions and are related to the ratios of baryon number susceptibilities of corresponding orders. The products of moments are found to have values significantly below the Skellam expectation and close to expectations based on independent proton and antiproton production. The measurements are compared to a transport model calculation to understand the effect of acceptance and baryon number conservation and also to a hadron resonance gas model.

Our aim was to investigate systemic nitric oxide (NO) production and its potential determinants such as insulin resistance, dyslipidemia, and circulating methylated analogs of L-arginine in uncomplicated essential hypertension (EH). Nineteen newly diagnosed, untreated male subjects with mild pure uncomplicated EH and 11 normotensive controls were studied at rest after an overnight fast. The groups had comparable age, body mass index, creatinine clearance, cholesterol, fasting glucose, and insulin. In hypertensives, the urinary excretion rate of nitrite plus nitrate (Unox), an index of endogenous NO production, was depressed (56+/-17 vs. 77+/-23 micromol/mmol creatinine; p < 0.05), whereas plasma levels of asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NO synthesis, were increased (2.4+/-1.1 vs. 1.1+/-0.7 microM; p < 0.005). Circulating concentrations of symmetric dimethylarginine were similar in both groups (1.4+/-1.3 vs. 1.5+/-1.1 microM; p = NS). The L-arginine-to-ADMA ratio was reduced in hypertension (3.3+/-0.5 vs. 4.5+/-0.8; p < 0.001 for In-transformed data). There was no correlation between Unox and either the magnitude of insulin resistance or dyslipidemia in EH. Thus in male subjects with EH, endogenous systemic NO formation appears depressed, which is unrelated to accompanying insulin resistance or dyslipidemia. Circulating ADMA levels are increased in uncomplicated EH, which may be of potential relevance.

The cementitious composites have different properties in the changing environment. Thus, knowing their mechanical properties is very important for safety reasons. The most important in the case of concrete is the Compressive strength (CS). To predict the CS of concrete Machine learning (ML) approaches has been essential. This study includes the collection of data from the experimental work and the application of ML techniques to predict the CS of concrete containing fly ash. The chemical and physical properties of all the materials used in this study were evaluated. Although, the emphasis of this research is on the use of supervised machine learning algorithms to forecast the CS of concrete. The Gene expression programming (GEP), Artificial neural network (ANN), and Decision tree (DT) algorithms were investigated for the prediction of outcome (CS). Concrete samples (cylinders) with different mix ratios were cast and tested at various ages to maintain the required data for applying it to run the models. Total 98 data points were collected from the experimental approach, in which seven parameters namely cement, fly ash, superplasticizer, coarse aggregate, fine aggregate, water, and days were taken as input to predict the output which was CS parameter. The experimental data is further validated by mean of k-fold cross-validation using R2, root mean error (RME), and Root mean square error (RMSE). In addition, statistical checks were incorporated to evaluate the model performance. In comparison, the bagging algorithm shows high accuracy towards the prediction of outcome as indicated by its high coefficient correlation (R2) value equals to 0.95, while R2 value for GEP, ANN and DT comes to 0.86, 0.81 and 0.75 respectively.

In 1883 Kjeldahl devised a method for the determination of nitrogen, which has become a classical measurement in analytical chemistry and has been used extensively over the past 130 years. In the original method, sulfuric acid alone was used as a digestion medium. The use of a catalyst in Kjeldahl digestion accelerates oxidation and completes the digestion to allow the subsequent determination of nitrogen. Mercury (its use being in decline because of environmental concerns), selenium, and copper are the catalysts of choice, though for certain applications titanium has found some usage. Short digestion times in association with maximum nitrogen recovery may be achieved by using a methodology based on experimental design and response surfaces, with microwave digestion processes, and with the aid of the couple sulfuric acid-hydrogen peroxide without catalyst. The quantification of distilled ammonia is generally achieved by titration; the ammonia is absorbed in an excess of boric acid, followed by titration with standard acid in the presence of a suitable indicator. The Kjeldahl method can be done with limited resources; nitrogen determination with the Kjeldahl method does not require expensive devices nor specialized techniques and is precise and accurate. The Kjeldahl method is used for calibrating other protein assays; it is still the primary reference method for protein analysis today. The original method as presented by Kjeldahl has been continuously improved. Today's digestion systems offer safety both from a personal perspective and from an environmental point of view. The determination of nitrogen content is a frequently conducted analysis in industry and commerce, and numerous organizations have official methods. The use of instrumental finish in Kjeldhal applications will be the subject of the second part of this review.

The production of $J\hspace{-1.5pt}/\hspace{-0.45pt}\psi$ mesons in proton–proton collisions at $\sqrt{s}=7\ensuremath {~\mathrm {TeV}}$ is studied with the LHCb detector at the LHC. The differential cross-section for prompt $J\hspace{-1.5pt}/\hspace{-0.45pt}\psi$ production is measured as a function of the $J\hspace{-1.5pt}/\hspace{-0.45pt}\psi$ transverse momentum pT and rapidity y in the fiducial region ${\ensuremath{p_{\mathrm{T}}}}\in[0;14]{\ensuremath{~\mathrm{GeV}\mskip-2mu/\mskip-1mu c}}$ and y∈[2.0;4.5]. The differential cross-section and fraction of $J\hspace{-1.5pt}/\hspace{-0.45pt}\psi$ from b-hadron decays are also measured in the same pT and y ranges. The analysis is based on a data sample corresponding to an integrated luminosity of 5.2 pb−1. The measured cross-sections integrated over the fiducial region are for prompt ${\ensuremath{J\hspace{-1.5pt}/\hspace{-0.45pt}\psi}}$ production and for $J\hspace{-1.5pt}/\hspace{-0.45pt}\psi$ from b-hadron decays, where the first uncertainty is statistical and the second systematic. The prompt ${\ensuremath{J\hspace{-1.5pt}/\hspace{-0.45pt}\psi}}$ production cross-section is obtained assuming no $J\hspace{-1.5pt}/\hspace{-0.45pt}\psi$ polarisation and the third error indicates the acceptance uncertainty due to this assumption.

Abstract The paper presents properties of nanomaterials and methods of their principal applications. Environmental aspects of using nanomaterials and reasons for their toxicity are also reviewed. The vast part of the paper is devoted to properties, application and market of silver nanoparticles. Their biocidal activity is clarified. However, silver nanoparticles may cause environmental pollution. Reasons for their toxicity have been also described.

Abstract In this work, the technology of nano‐ and micro‐scale particle reinforcement concerning various polymeric fiber‐reinforced systems including polyamides (PAs), polyesters, polyurethanes (PUs), polypropylenes (pps), and high‐performance/temperature engineering polymers such as polyimide (PI), poly(ether ether ketone) (PEEK), polyarylacetylene (PAA), and poly p ‐phenylene benzobisoxazole (PBO) is reviewed. When the diameters of polymer fiber materials are shrunk from micrometers to submicrons or nanometers, there appear several unique characteristics such as very large surface area to volume ratio (this ratio for a nanofiber can be as large as 10 3 times of that of a microfiber), flexibility in surface functionalities and superior mechanical performance (such as stiffness and tensile strength) compared to any other known form of the material. While nanoparticle reinforcement of fiber‐reinforced composites has been shown to be a possibility, much work remains to be performed in order to understand how nanoreinforcement results in dramatic changes in material properties. The understanding of these phenomena will facilitate their extension to the reinforcement of more complicated anisotropic structures and advanced polymeric composite systems. Copyright © 2008 John Wiley &amp; Sons, Ltd.

We report the first measurements of the moments---mean ($M$), variance (${\ensuremath{\sigma}}^{2}$), skewness ($S$), and kurtosis ($\ensuremath{\kappa}$)---of the net-charge multiplicity distributions at midrapidity in $\mathrm{Au}+\mathrm{Au}$ collisions at seven energies, ranging from $\sqrt{{s}_{\mathit{\text{NN}}}}=7.7$ to 200 GeV, as a part of the Beam Energy Scan program at RHIC. The moments are related to the thermodynamic susceptibilities of net charge, and are sensitive to the location of the QCD critical point. We compare the products of the moments, ${\ensuremath{\sigma}}^{2}/M$, $S\ensuremath{\sigma}$, and $\ensuremath{\kappa}{\ensuremath{\sigma}}^{2}$, with the expectations from Poisson and negative binomial distributions (NBDs). The $S\ensuremath{\sigma}$ values deviate from the Poisson baseline and are close to the NBD baseline, while the $\ensuremath{\kappa}{\ensuremath{\sigma}}^{2}$ values tend to lie between the two. Within the present uncertainties, our data do not show nonmonotonic behavior as a function of collision energy. These measurements provide a valuable tool to extract the freeze-out parameters in heavy-ion collisions by comparing with theoretical models.

Concrete is a widely used construction material, and cement is its main constituent. Production and utilization of cement severely affect the environment due to the emission of various gases. The application of geopolymer concrete plays a vital role in reducing this flaw. This study used supervised machine learning algorithms, decision tree (DT), bagging regressor (BR), and AdaBoost regressor (AR) to estimate the compressive strength of fly ash-based geopolymer concrete. The coefficient of determination (R2), mean absolute error, mean square error, and root mean square error were used to evaluate the model's performance. The model's performance was further confirmed using the k-fold cross-validation technique. Compared to the DT and AR model, the bagging model was more effective in predicting results, with an R2 value of 0.97. The lesser values of the errors (MAE, MSE, RMSE) and higher values of the R2 were the clear indications of the better performance of the model. Additionally, a sensitivity analysis was conducted to ascertain the degree of contribution of each parameter towards the prediction of the results. The application of machine learning techniques to predict concrete's mechanical properties will benefit the area of civil engineering by saving time, effort, and resources.

In this report, we present the results of our investigations into the elucidation of the chemical structure of moieties responsible for the blue and green luminescence of CDs derived from the microwave-assisted pyrolysis of citric acid in the presence of urea. The molecular fluorophore that forms during the synthesis of green fluorescing CDs is 4-hydroxy-1H-pyrrolo[3,4-c]pyridine-1,3,6(2H,5H)-trione (HPPT).

We report a measurement of the exclusive ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\Lambda}}_{c}^{\ensuremath{-}}$ cross section as a function of center-of-mass energy near the ${\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\Lambda}}_{c}^{\ensuremath{-}}$ threshold. A clear peak with a significance of $8.2\ensuremath{\sigma}$ is observed in the ${\ensuremath{\Lambda}}_{c}^{+}{\ensuremath{\Lambda}}_{c}^{\ensuremath{-}}$ invariant mass distribution just above threshold. With an assumption of a resonance origin for the observed peak, a mass and width of $M=[{4634}_{\ensuremath{-}7}^{+8}(\mathrm{stat}{)}_{\ensuremath{-}8}^{+5}(\mathrm{syst})]\text{ }\text{ }\mathrm{MeV}/{c}^{2}$ and ${\ensuremath{\Gamma}}_{\mathrm{tot}}=[{92}_{\ensuremath{-}24}^{+40}(\mathrm{stat}{)}_{\ensuremath{-}21}^{+10}(\mathrm{syst})]\text{ }\text{ }\mathrm{MeV}$ are determined. The analysis is based on a study of events with initial-state-radiation photons in a data sample collected with the Belle detector at the $\ensuremath{\Upsilon}(4S)$ resonance and nearby continuum with an integrated luminosity of $695\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider.

In this study the recently developed electron density of delocalized bonds (EDDB) is used to define a new measure of aromaticity in molecular rings.