The Structural Formation of Cement Stone Modified by a Solution of Superabsorbent Polymer

With the development of 3D technologies in construction, the development of formulations that are indifferent to the influence of the environment is in demand. Conditions of intense water loss from cement systems arise during the layer-by-layer printing process. This leads to a decrease in density, high shrinkage, and a decrease in the strength and durability of the composite. The use of superabsorbent polymer (SAP) solutions, in contrast to granules, will provide hardening Portland cement with a water supply for internal care of hydration processes. The aim of the work is to study the effect of SAP solution on the processes of structure formation of cement stone, hardening in unfavorable conditions. In this paper, the features of the structure formation of cement systems in the presence of SAP are established. It is shown that the use of polymer in an amount of no more than 1.5% by the weight of Portland cement provides the formation of a more perfect crystalline structure of the cement stone, which allows for an increase in the degree of cement hydration. When the amount of SAP is ≥ 1.5% by the weight of Portland cement, a decrease in the intensity of the maxima corresponding to hydration products is observed.

Novel U-Pb isotopic zircon data on the rhyolite of the Saf’yanovskoe Cu-Zn deposit (Middle Urals)

Research subject. Zircons from the Saf’yanovskoe Cu-Zn deposit rhyolite (Middle Urals). For the first time, zircon U-Pb dating for the rhyolite of the ore-bearing volcanic-sedimentary rocks of the Saf’yanovskoe deposit was performed. The volcanites are characterized by an andesite-rhyodacite composition and are localized at the southern edge of the Rezhevskaya structural-formation zone (SFZ) of the Eastern Ural megazone. A number of publications assign these rocks either to the basalt-rhyolite formation of the Middle Devonian, or to the basalt-andesite-dacite-rhyolite formation of the Lower-Middle Devonian.Aim. To estimate the age of the ore-bearing volcanic rocks under study using the U-Pb SHRIMP-II isotop ic system of zircon from the rhyolite of the eastern side of the Saf’yanovskoe deposit. By its chemical composition, the rhyolite belongs to the silicic varieties of subvolcanic rocks. Methods and results. The U-Pb isotopic system of zircon was studied by 5-collector mass-spectrometer of high precision and emission of the secondary ions SHRIMP-II (ASI, Australia) in the VSЕGEI Institute. U-Pb relations were investigated by a procedure developed by I.S. Williams. The U-Pb data obtained based on 13 zircon grains showed the age of 422.8 ± 3.7 Ma. Conclusions. The U-Pb dating of zircon obtained previously from the lens-shaped andesite bodies of the western side of the Safyanovskoe deposit gave the age of 422.8 Ma, which corresponds to the Przydoli series epoch of the Upper Silurian. We established that, among the volcanic rocks of the Saf’yanovskoe deposit, the effusive formations of the Upper Silurian are present.

Lignin and Xylan as Interface Engineering Additives for Improved Environmental Durability of Sustainable Cellulose Nanopapers

Cellulose materials and products are frequently affected by environmental factors such as light, temperature, and humidity. Simulated UV irradiation, heat, and moisture exposure were comprehensively used to characterize changes in cellulose nanopaper (NP) tensile properties. For the preparation of NP, high-purity cellulose from old, unused filter paper waste was used. Lignin and xylan were used as sustainable green interface engineering modifiers for NP due to their structural compatibility, low price, nontoxic nature, and abundance as a by-product of biomass processing, as well as their ability to protect cellulose fibers from UV irradiation. Nanofibrillated cellulose (NFC) suspension was obtained by microfluidizing cellulose suspension, and NP was produced by casting films from water suspensions. The use of filler from 1 to 30 wt% significantly altered NP properties. All nanopapers were tested for their sensitivity to water humidity, which reduced mechanical properties from 10 to 40% depending on the saturation level. Xylan addition showed a significant increase in the specific elastic modulus and specific strength by 1.4- and 2.8-fold, respectively. Xylan-containing NPs had remarkable resistance to UV irradiation, retaining 50 to 90% of their initial properties. Lignin-modified NPs resulted in a decreased mechanical performance due to the particle structure of the filler and the agglomeration process, but it was compensated by good property retention and enhanced elongation. The UV oxidation process of the NP interface was studied with UV-Vis and FTIR spectroscopy, which showed that the degradation of lignin and xylan preserves a cellulose fiber structure. Scanning electron microscopy images revealed the structural formation of the interface and supplemented understanding of UV aging impact on the surface and penetration depth in the cross-section. The ability to overcome premature aging in environmental factors can significantly benefit the wide adaption of NP in food packaging and functional applications.

Influence of Asphalt Emulsion Inclusion on Fly Ash/Hydrated Lime Alkali-Activated Material

Supplementary cementitious materials have been widely used to reduce the greenhouse gas emissions caused by ordinary Portland cement (OPC), including in the construction of road bases. In addition, the use of OPC in road base stabilization is inefficient due to its moisture sensitivity and lack of flexibility. Therefore, this study investigates the effect of hybrid alkali-activated materials (H-AAM) on flexibility and water prevention when used as binders while proposing a new and sustainable material. A cationic asphalt emulsion (CAE) was applied to increase this cementless material’s resistance to moisture damage and flexibility. The physical properties and structural formation of this H-AAM, consisting of fly ash, hydrated lime, and sodium hydroxide, were examined. The results revealed that the addition of CAE decreased the material’s mechanical strength due to its hindrance of pozzolanic reactions and alkali activations. This study revealed decreases in the cementitious product’s peak in the x-ray diffraction analysis (XRD) tests and the number of tetrahedrons detected in the Fourier transform infrared spectroscopy analysis (FTIR) tests. The scanning electron microscope (SEM) images showed some signs of asphalt films surrounding hybrid alkali-activated particles and even some unreacted FA particles, indicating incomplete chemical reactions in the study material’s matrix. However, the H-AAM was still able to meet the minimum road base strength requirement of 1.72 MPa. Furthermore, the toughness and flexibility of the H-AAM were enhanced by CAE. Notably, adding 10% and 20% CAE by weight to the hybrid alkali-activated binder produced a significant advantage in terms of water absorption, which can be explained by its influence on the material’s consolidation of its matrices, resulting in significant void reductions. Hence, the outcomes of this study might reveal an opportunity for developing a new stabilizing agent for road bases with water-prevention properties and flexibility that remains faithful to the green construction material concept.

Silicon nanorod formation from powder feedstock through co-condensation in plasma flash evaporation and its feasibility for lithium-ion batteries

Si nanowires/nanorods are known to enhance the cycle performance of the lithium-ion batteries. However, viable high throughput production of Si nanomaterials has not yet attained as it requires in general expensive gas source and low-rate and multiple-step approach. As one of the potential approaches, in this work, we report the fast-rate Si nanorod synthesis from low-cost powder source by the modified plasma flash evaporation and the fundamental principle of structural formation during gas co-condensation. In this process, while Si vapors are formed in high temperature plasma jet, molten copper droplets are produced separately at the low temperature region as catalysts for growth of silicon nanorods. Si rods with several micrometers long and a few hundred of nanometers in diameter were produced in a single process at rates up to 40 µm s−1. The growth of the Si nanorods from powder source is primarily characterized by the vapor–liquid–solid growth which is accelerated by the heat extraction at the growth point. The battery cells with the Si nanorods as the anode have shown that a higher capacity and better cyclability is achieved for the nanorods with higher aspect ratios.

To What Extent Did Assumptions About Local Ethnic Identities, Fostered Amongst UN Officials During the Bosnia Mission, Frame Their Policies for the Kosovo Mission?

<p>This thesis focuses on the role of an international actor - United Nations (UN) - and its missions in Bosnia and Herzegovina (UNMBiH) during 1992-1995 and Kosovo (UNMIK) in the post war conflict period of peace building. It scrutinizes the tenor of UN peace building missions in these territories by analysing the scope of the policies introduced and the effectiveness (or ineffectiveness) of the international actors' activities during the times of war in Bosnia and Herzegovina (BiH) before the conflict in Kosovo and Metohija (KiM); and the current situation in these two territories. The thesis will also argue that the ethnic identities played a critical role in relation building between the UN and ethnic groups, where the one ethnic group (Serbs) was recognised as a crucial factor for the conflict's escalation and development. A further focus in this thesis is not only to provide constructive discussion of the ineffectiveness of policies and missions introduced by International Actors (IA) but also to challenge the UN and IA's decision for non-intervention in BiH and to address the consequence of subsequent humanitarian-military intervention in KiM. This paper outlines an analysis of the lack of literature relating to the historical-sociological perspective of the ethnic groups' in BiH. The lack of understanding of the complex relationships among the ethnicities is an additional gap. This is exacerbated by the lack of understanding of the complex relationships among the ethnicities, within itself, as well as the differences among the groups within each ethnic group. It appears that the literature is unable to acknowledge the structural formation of societies in BiH, and to make proper segmentation in understanding the particular group of people (Rex, 2001) as a collection of peoples with different sociological characteristics combined into something called 'ethnicity'. The handicap of such literature leads to the categorisation and generalisation of ethnicities; not at one particular area of an ethnic group's presence but to the generalisation of the peoples' ethnicities (all Serbs are barbarous, similar to the Germans after WWII). This paper argues that such generalisations developed the notion that the particular ethnic group (Serbs) has an 'evil' character, regardless of the territorial occupation (Bosnia as well as Serbia and Diaspora). In addition, the lack of recognising Serbs as a people composed of different individual (local) ethnic groups led to the global generalisation about Serbs. And yet, such generalisations, by the modern western actors, i.e. UN, EU (European Union) and USA (United States of America), led to the employment of negative assumptions about the Serbs which served as a tool for, and added impetus to, the implementation of a strategy to achieve the Western objectives of the devaluation of Serbian dominance in Bosnia and across the Balkan Peninsula. Therefore the quality of literature, in addressing the questions about the conflict in BiH and later KiM, beside its attempts to offer some sustainable answers, remains inadequate and poor. This unsubstantiated position, offered by many involved in former-Yugoslavian conflict discussions, to offer an informed conclusion, persists as a never-ending debate. Yet, the discourse about the guilty factor in BiH and KiM remains in the shape of the 'evil' Serbian nation.</p>

To What Extent Did Assumptions About Local Ethnic Identities, Fostered Amongst UN Officials During the Bosnia Mission, Frame Their Policies for the Kosovo Mission?

<p>This thesis focuses on the role of an international actor - United Nations (UN) - and its missions in Bosnia and Herzegovina (UNMBiH) during 1992-1995 and Kosovo (UNMIK) in the post war conflict period of peace building. It scrutinizes the tenor of UN peace building missions in these territories by analysing the scope of the policies introduced and the effectiveness (or ineffectiveness) of the international actors' activities during the times of war in Bosnia and Herzegovina (BiH) before the conflict in Kosovo and Metohija (KiM); and the current situation in these two territories. The thesis will also argue that the ethnic identities played a critical role in relation building between the UN and ethnic groups, where the one ethnic group (Serbs) was recognised as a crucial factor for the conflict's escalation and development. A further focus in this thesis is not only to provide constructive discussion of the ineffectiveness of policies and missions introduced by International Actors (IA) but also to challenge the UN and IA's decision for non-intervention in BiH and to address the consequence of subsequent humanitarian-military intervention in KiM. This paper outlines an analysis of the lack of literature relating to the historical-sociological perspective of the ethnic groups' in BiH. The lack of understanding of the complex relationships among the ethnicities is an additional gap. This is exacerbated by the lack of understanding of the complex relationships among the ethnicities, within itself, as well as the differences among the groups within each ethnic group. It appears that the literature is unable to acknowledge the structural formation of societies in BiH, and to make proper segmentation in understanding the particular group of people (Rex, 2001) as a collection of peoples with different sociological characteristics combined into something called 'ethnicity'. The handicap of such literature leads to the categorisation and generalisation of ethnicities; not at one particular area of an ethnic group's presence but to the generalisation of the peoples' ethnicities (all Serbs are barbarous, similar to the Germans after WWII). This paper argues that such generalisations developed the notion that the particular ethnic group (Serbs) has an 'evil' character, regardless of the territorial occupation (Bosnia as well as Serbia and Diaspora). In addition, the lack of recognising Serbs as a people composed of different individual (local) ethnic groups led to the global generalisation about Serbs. And yet, such generalisations, by the modern western actors, i.e. UN, EU (European Union) and USA (United States of America), led to the employment of negative assumptions about the Serbs which served as a tool for, and added impetus to, the implementation of a strategy to achieve the Western objectives of the devaluation of Serbian dominance in Bosnia and across the Balkan Peninsula. Therefore the quality of literature, in addressing the questions about the conflict in BiH and later KiM, beside its attempts to offer some sustainable answers, remains inadequate and poor. This unsubstantiated position, offered by many involved in former-Yugoslavian conflict discussions, to offer an informed conclusion, persists as a never-ending debate. Yet, the discourse about the guilty factor in BiH and KiM remains in the shape of the 'evil' Serbian nation.</p>

Evidentiality in Selibu

Selibu is a Mandarin-Khams Tibetan mixed language with about 900 native speakers in northwest Yunnan, People’s Republic of China. As a Form-Semantics mixed language, it derives most of its lexicon and grammatical morphemes from Southwest Mandarin and borrows its morphosyntactic and semantic structure from Alangu Tibetan. This article examines the contact-induced emergence of a five-category complex evidential system in Selibu with a detailed comparison with its source system in the model language, Alangu Tibetan. Our discussion focuses on the hybrid features of Selibu evidentiality in both forms and functions and also on its structural formation, which does not represent a Form-Semantics mixed type in this particular domain.

Gaivoron—Zavallia section of the Middle Pobuzhzhіa is the most representative part of the granulite complex of the Ukrainian Shield (structural-tectonophysical results and magnetometric studies)

In the article according to the geological and geophysical data of the well-exposed areas of development of Archean rocks of the Ukrainian Shield, two alternative approaches to establishing the structure and stratigraphy of the oldest granulite complexes are discuss. The outcrops of the enderbite-gneiss complex up to 3.6—3.8 billion years old are located along the Southern Bug River between the Gaivoron town and the Zavallia village. The first, «stratigenic-metamorphogenic» approach assumes that the main features of the composition and structure of the Lower Archean complexes are inherited from the original stratotypic strata. These strata are transformed in the conditions of quasi-isochemical metamorphism with preservation of the sequence of formation in section and the primary constitution in the form of stratification, rhythmicity, direction of change of their composition vertically and laterally. On the structural-formation map and geological section of the Gaivoron—Zavallia section, the Archean granulite complex is shown in the form of a synclinorium composed of four adjacent formations, which are equated to the world of metamorphosed volcanic-sedimentary rocks. The second, «deformation-metamorphogenic» approach, which is supported by the authors of this article, is based on the idea that the granulite complex of Pobuzhzhіa is a subvertically layered medium formed by tangential tectonic forces. The latter lead to shear deformations and displacement of matter at the atomic-molecular (with mineral transformation of rocks) and rock masses at the regional level. This creates structural and textural elements that are superimposed on the primary structure of rocks and often erase it. Field structural-tectonophysical, tectonofacial and magnetometric studies, its results are presented in the article. It was performed specifically to compare these two concepts. Magnetometric studies have shown that the enderbite-gneiss complex of the district by its magnetic characteristics belongs to the middle and lower crust of the Ukrainian Shield.