Carbides and Nitrides of Zirconium and Hafnium.

Among transition metal carbides and nitrides, zirconium, and hafnium compounds are the most stable and have the highest melting temperatures. Here we review published data on phases and phase equilibria in Hf-Zr-C-N-O system, from experiment and ab initio computations with focus on rocksalt Zr and Hf carbides and nitrides, their solid solutions and oxygen solubility limits. The systematic experimental studies on phase equilibria and thermodynamics were performed mainly 40-60 years ago, mostly for binary systems of Zr and Hf with C and N. Since then, synthesis of several oxynitrides was reported in the fluorite-derivative type of structures, of orthorhombic and cubic higher nitrides Zr3N4 and Hf3N4. An ever-increasing stream of data is provided by ab initio computations, and one of the testable predictions is that the rocksalt HfC0.75N0.22 phase would have the highest known melting temperature. Experimental data on melting temperatures of hafnium carbonitrides are absent, but minimum in heat capacity and maximum in hardness were reported for Hf(C,N) solid solutions. New methods, such as electrical pulse heating and laser melting, can fill the gaps in experimental data and validate ab initio predictions

ANALYSIS OF DESIGN FEATURES OF FLEXIBLE PAVEMENTS ON FEDERAL HIGHWAYS IN RUSSIA

Abstract. Nowadays the pavements of highways in Russia work under difficult conditions of constantly growing traffic volume. The current method for flexible pavements design has a number of serious disadvantages. It does not take into complete account the best practices in design and the actual operating conditions for highways. In a number of cases, this leads to the design of inefficient structures of pavements with a short service life.On a number of federal roads, there are observed rutting and premature wear out of road surface in the first years of the operation. Drainage sand layers and shallow drainage drains are quickly working out. Geosynthetic materials are sometimes used unreasonably. The design life of pavements does not comply with the current standards. In Russia the effective road construction materials are not yet completely used up, as well as local materials reinforced with astringents. The actual experience in operating various road structures with the identification of the most optimal solutions is still poorly considered, except for certain regions.Thus, an urgent need has arisen to develop standard designs of pavements for various natural and climatic conditions in Russia ensuring pavements' efficient operation. It is necessary to analyze the existing pavement designs on the federal highways under various road building climatic zones to develop the standard pavement designs.Keywords: flexible pavements, typical constructions of pavements

Experimental techniques to study structure and thermodynamics at ultra- high temperatures

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Remission in schizophrenia: results of cross-sectional with 6-month follow-up period and 1-year observational therapeutic studies in an outpatient population

<p>Abstract</p> <p>Background</p> <p>A standardized definition of remission criteria in schizophrenia was proposed by the International group of NC Andreasen in 2005 (low symptom threshold for the eight core Positive and Negative Syndrome Scale (PANSS) symptoms for at least 6 consecutive months).</p> <p>Methods</p> <p>A cross-sectional study of remission rate, using a 6-month follow-up to assess symptomatic stability, was conducted in two healthcare districts (first and second) of an outpatient psychiatric service in Moscow. The key inclusion criteria were outpatients with an <it>International Classification of Diseases</it>, 10th edition (ICD-10) diagnosis of schizophrenia or schizoaffective disorder. Remission was assessed using modern criteria (severity and time criteria), PANSS and Global Assessment of Functioning (GAF). Patients who were stable but did not satisfied the symptomatic criteria were included in a further 1-year observational study, with the first group (first district) receiving risperidone (long-acting, injectable) (RLAI) and the second group (second district) continuing to receiving routine treatment. Symptoms were assessed with PANSS, social functioning with the personal and social performance scale, compliance with rating of medication influences scale, and extrapyramidal side effects with the Simpson-Angus scale.</p> <p>Results</p> <p>Only 64 (31.5%) of 203 outpatients met the criteria for symptomatic remission in the cross-sectional study, but at the end of the 6-month follow-up period, 158 (77.8%) were stable (irrespective of remission status). Among these only 53 (26.1%) patients fulfilled the remission criteria. The observational study had 42 stable patients in the RLAI group and 35 in the routine treatment group: 19.0% in the RLAI group and 5.7% in the control group met remission criteria after 12 months of therapy. Furthermore, reduction of PANSS total and subscale scores, as well as improvement in social functioning, was more significant in the first group.</p> <p>Conclusions</p> <p>Only around one-quarter of our outpatient schizophrenic population met full remission criteria. Use of RLAI gave a better remission rate than achieved in standard care with routine treatment. Criteria for remission should take into account clinical course and functioning to support clinical care.</p

Control of the combustion process and emission formation in marine gas engines

A smooth transition to the use of gas engines instead of conventional engines in marine shipping is a logical pathway for compliance with tightening environmental regulations. Currently, five major gas engine concepts are applied in maritime sector. In this paper, a review of the marine gas engine concepts was performed with a focus on the control of combustion and emission. To assess all the contributors to combustion and the emission formation process, three main factors were outlined: design, operational parameters and fuel. The assessment of gas engines was conducted based on these factors. The present paper helps to provide an understanding of the current progress in the development of marine gas engines towards improving of combustion efficiency and reducing the emissions. Moreover, the knowledge gaps, particularly in four-stroke marine high-pressure gas engines, were identified.acceptedVersio

Tunable Low Density Palladium Nanowire Foams

Nanostructured palladium foams offer exciting potential for applications in diverse fields such as catalyst, fuel cell, and particularly hydrogen storage technologies. We have fabricated palladium nanowire foams using a cross-linking and freeze-drying technique. These foams have a tunable density down to 0.1% of the bulk, and a surface area to volume ratio of up to 1,540,000:1. They exhibit highly attractive characteristics for hydrogen storage, in terms of loading capacity, rate of absorption and heat of absorption. The hydrogen absorption/desorption process is hysteretic in nature, accompanied by substantial lattice expansion/contraction as the foam converts between Pd and PdHx.Comment: 17 pages, 4 figure

The Northern Sea Route as a reefer container transport corridor

The use of the Northern Sea Route as a transport corridor between the European and Asian continents is currently attracting increased interest in the trade, economic and logistic communities. The possibility to deliver cargo from Europe to Asia and back much faster is extremely attractive for cargo owners in the conditions of instability of the development of modern regional economic trends, turbulence of the global economy as a whole. In the conditions of rapidly changing market demand and supply in the markets of food products in Europe and Asia, the use of the Northern Sea Route as the shortest route between two continents is becoming especially popular for operators in the field of perishable goods logistics. Nevertheless, the possibility of using the Northern Sea Route is significantly limited by the complexity of transporting cargo in the autumn-winter period due to the need for ice pilotage. Assessment of the competitiveness of the Northern Sea Route compared to traditional routes seems to be an important aspect of the formation of consumer preferences among the owners of perishable goods and operators of transportation in reefer containers. The paper proposes a method for assessing the competitiveness of the Northern Sea Route with respect to alternative routes, taking into account the specifics of transportation of perishable goods in reefer containers. Criteria and indicators of competitiveness of the compared routes are presented, covering the full range of economic and technological components that determine the handling and transportation of perishable goods in reefer containers

Medieval Chersonesus in the Second Half of the 13th Century: a city, a village, a trading post?

The paper addresses the results of the study of medieval Chersonesus as a municipal structure in the second half of 13th century. Historiography was previously dominated by the viewpoint that in that time period Chersonesus remained a major trade, craft and cultural center with buildings of monumental architecture. Currently, it is considered that it remained an ordinary provincial Byzantine center. Specific archaeological complexes with frequent finds of the second half of the 13th century were identified and studied in all districts of the settlement, and were found to be associated with layers of destruction and fires. Two layers of destruction (fire), dated to the 13th and 14th centuries, have been recorded in the Port district. These late Byzantine layers are represented by all complexes of materials (primarily, archaeological), which allow to conclude that at the beginning of the second half of the 13th century Chersonesus was a typical provincial Byzantine city on the edge of the Golden Horde Ecumene. At the turn of the fourth quarter of the 13th century (in 1278), the city was destroyed and has not been restored, with the exception of the Port district, which became a small 14th century village

In-situ phase diagram determination of the HfO2-Ta2O5 binary up to 3000˚C

Ceramic equilibrium phase diagrams have proven to be difficult to produce for materials above 1500 ˚C. We demonstrate that in-situ X-ray diffraction on laser heated levitated samples can be used to elucidate phase fields. In these experiments, solid spherical samples are suspended and rotated by a gas stream through a conical nozzle levitator, heated by a 400 W CO2 laser at Argonne National Labs beamline 6-ID-D. Please click on the link below for the full content

Development of typical flexible road pavement catalog for regional and intermunicipal highways in Russian Federation (using the example of the Republic of Bashkortostan)

Road pavements in Russia are now working in difficult conditions of ever-growing vehicular traffic intensity. Current methodology for designing flexible road pavements has a number of serious shortcomings, where the best design experience and actual operating conditions of highways are not fully taken into account. In some cases, this leads to ineffective pavement structures design with a short service life. On many roads, rutting and premature wear of road surfaces appear already in the first years of their operation. Drainage systems are silted up in the first years of working. At the same time, geosynthetic materials are sometimes used unreasonably. The service life of roadway surfaces does not comply with the current regulations. In Russia, effective road-building materials are not yet fully used, local road-building materials and industrial waste reinforced with binders are little used. With exception of certain regions of the country, actual experience of operating various road structures with identification of the most optimal solutions is still poorly subject to consideration. Thus, there is an urgent need to develop designs of typical road pavements for various regions of Russia, which will ensure their efficient operation. To develop typical pavement designs, it is necessary to analyze existing ones in real conditions of their operation