bluuebunny/crossref_metadata_2025 huggingface dataset:
John Hunter's Directions for preserving animals
Authors: Strekopytov Stanislav
Published: October 2018

Directions for preserving animals, an undated anonymous pamphlet, privately published by the famous anatomist John Hunter (1728–1793), has not been a subject of a dedicated study so far in spite of its importance as a set of instructions influencing zoological collecting throughout the nineteenth century. A donation entry in the 1788 edition of Regulations and laws of the Lyceum Medicum Londinense allowed assigning 1788 as the most probable publication year of Hunter's pamphlet. The bibliographic analysis of Hunter's private press publications shows that the pamphlet was likely to have been produced by the same press. The pamphlet was reprinted in an amended form in 1809, and further amendments were done for the 1826 and 1835 editions published by the Royal College of Surgeons in London. In spite of Richard Owen (1804–1892) claiming a (co-)authorship of the 1835 edition, there is no evidence that his role exceeded minor editorial corrections. Since Owen made a reference in his correspondence to Hunter's manuscript instructions that he supposedly used in the preparation of the 1835 edition, an attempt was made to trace published and unpublished manuscript instructions for zoological collecting that could be attributed to Hunter. Manuscripts of the Society for Promoting Natural History preserved at the Linnean Society of London showed involvement of John Hunter and Everard Home (1756–1832) in the preparation of a hitherto undescribed comprehensive set of instructions for natural history collectors that was planned to be published by the Society.
The Scottish National Antarctic Expedition, 1902–1904: reconstructing the missing geological report
Authors: Stone Philip
Published: October 2018

The Scottish National Antarctic Expedition (1902–1904) made the first topographical survey and scientific investigation of Laurie Island, one of the South Orkney Islands, and completed an extensive oceanographical research programme in the Scotia and Weddell Seas. When the expedition returned to Scotland, the leader, William Speirs Bruce, embarked on an ambitious attempt to publish the expedition's scientific results in a series of high-quality reports. Sadly, by the time it came to the eighth volume (on geology) his funds were exhausted, and the series was abandoned. Nevertheless, many of the contributions that had been intended for that volume were produced; some were published elsewhere whilst unpublished proofs and archive notes survive for others. From these various sources the volume as planned by Bruce can be reconstructed. The key contributor was J. H. H. Pirie, a medical doctor and primarily the expedition's surgeon. Despite his limited relevant experience his geological observations were commendable, with the notable exception of an important palaeontological misidentification that was inexplicably supported by eminent British experts. The archive material illuminates the background to Pirie's contributions and the ways in which his unpublished work came to be preserved.
Sur les produits de déshydratation du gypse
Authors: Cano René , Chatelain Pierre
Published: October 2018

L'étude au moyen des rayons X du sulfate de calcium paraît montrer qu'il n'existe que sous trois formes cristallographiquement bien définies : le gypse, l'anhydrite soluble, contenant des quantités très variables d'eau zéolitique et l'anhydrite insoluble.
Analyse thermique différentielle de quelques minéraux sulfurés et arséniés de fer, nickel et cobalt
Authors: Asensio I. , Sabatier Germain
Published: October 2018

On donne les courbes d'analyse thermique différentielle des minéraux suivants : pyrrhotine, pyrite, mispickel, loellingite — millerite, nickeline, gersdorffite — linnéite, cobaltine, skutterudite. On montre que les chaleurs d'oxydation de ces minéraux, déduites de l'examen des courbes, peuvent être calculées, en première approximation, à partir de leur composition chimique.
Analyse thermique différentielle des minerais sulfurés
Authors: Lévy Claude
Published: October 2018

L'analyse thermique différentielle, dans l'air, des sulfures constituants des minerais, donne pour chacun d'entre eux une courbe d'oxydation caractéristique et peut donc être utilisée comme moyen de détermination. La méthode est d'abord appliquée à certains minéraux du B. G. P. : pyrite, blende, galène, marcasite. On examine ensuite, à titre d'exemple, les courbes d'une famille de minéraux d'un même métal : chalcopyrite, cuivre gris, bornite, covellite et chalcocite — on compare de même les minéraux d'argent : argent natif, argyrose, proustite et pyrargyrite. Pour tous les minéraux étudiés, on observe un ou plusieurs phénomènes endothermiques caractéristiques du métal entrant dans la combinaison, tandis que les crochets exothermiques sont caractéristiques de l'espèce analysée. Enfin, la méthode est essayée sur un mélange artificiel, puis sur un minerai complexe : on observe simplement l'addition des phénomènes enregistrés sur les minéraux isolés. La méthode permet donc la détermination d'un minerai complexe. Les perspectives de l'analyse quantitative sont envisagées.
Structure cristalline de la bromo-antipyrine
Authors: Romain P.
Published: October 2018

La bromo-antipyrine cristallise dans le système rhomboédrique. Les dimensions de la maille sont :

a = c = 15,70 Â (Maille multiple 1 <3 = 26,81 Â) a =152°45' (hexagonale (c= 7,90 Â)

La maille rhomboédrique contient 6 molécules. Le groupe de symétrie est R 3 (hémiédrie centrée) .

La structure a été déterminée avec une bonne précision (R = 0,06) sur la projection (III)rh ((001)hex) ; avec une précision moyenne (R = 0,158) sur la projection (ii2)rh ((010) hex).

Les procédés classiques de détermination de la «structure de départ» s'étant révélés peu efficaces, il a été fait usage de méthodes particulières.

La molécule de bromo-antipyrine est formée d'un cycle pyrazolique et d'un cycle benzénique non coplanaires. Les forces de liaison intramoléculaires ont été précisées ; les liaisons intermoléculaires montrent une association des molécules par couples.
Sur la Dumontite de Shinkolobwe (Katanga)
Authors: Thoreau Jacques , Van Meerssche Maurice , Protas Jean
Published: October 2018

L'analyse chimique d'un échantillon de dumontite montre que la formule de ce minéral rare est : Pb₂ (UO₂)₃ (PO₄)₂ (OH)₄. 3 H₂O ; densité : 5,65. La formule chimique et les propriétés optiques sont en bon accord avec celles du minéral initialement décrit. L'étude des diagrammes de Weissenberg (strates hko, hk1, hk2 ; hol, h1l, h2l) montre l'existence d'une macle suivant le plan (100). Les paramètres de la maille sont : a = 8,16 ± 0,03 À ; b = 16,73 ± 0,03 À ; c = 7,02 ± 0,03 À ; β = 110° ; Z = 2. Groupe spatial : P2₁ ou P2₁/m.
Contribution à l'étude de la formation et de la cinétique des solutions solides obtenues dans le système KCl-KBr à température ordinaire, par compression des poudres cristallines
Authors: Thrierr Aline
Published: October 2018

L'expérimentation, telle que nous l'avons conduite, a mis en évidence ces réactions de l'état solide par l'analyse réfractométrique en immersion, répétée au cours du temps pour l'étude cinétique. L'analyse réfractométrique a été rattachée pour les repérages de composition chimique à l'analyse diffractométrique de quelques solutions solides dominantes typiques. Pour des grains cristallins de dimensions comprises entre 10 et 20µ la fréquence statistique des solutions solides dominantes que nous avons étudiées évolue suivant trois stades successifs, après relâchement de la compression et à température ordinaire. Des fonctions représentatives simples schématisent ces trois stades.
Étude comparative des défauts instrumentaux dans trois types de diffractomètres à rayons X (méthode des poudres)
Authors: Simon Bernard , Kern Raymond
Published: October 2018

Les défauts instrumentaux d'ordre géométrique sont étudiés dans trois types de difïractomètres de poudre (appareil classique de Bragg et deux montages par transmission). On se limite aux défauts suivants : épaisseur de l'échantillon (absorption) — planéité de l'échantillon (divergence horizontale) — effets de hauteur du faisceau incident et de la fente d'analyse.

On calcule pour quelques angles de Bragg le profil des raies par la théorie du produit de convolution, et on donne les résultats d'une vérification expérimentale.
Enhancement of X-ray emission from nanocolloidal gold suspensions under double-pulse excitation
Authors: Hsu Wei-Hung , Masim Frances Camille P , Balčytis Armandas , Huang Hsin-Hui , Yonezawa Tetsu , Kuchmizhak Aleksandr A , Juodkazis Saulius , Hatanaka Koji
Published: October 2018

Enhancement of X-ray emission was observed from a micro-jet of a nano-colloidal gold suspension in air under double-pulse excitation of ultrashort (40 fs) near-IR laser pulses. Temporal and spatial overlaps between the pre-pulse and the main pulse were optimized for the highest X-ray emission. The maximum X-ray intensity was obtained at a 1–7 ns delay of the main pulse irradiation after the pre-pulse irradiation with the micro-jet position shifted along the laser beam propagation. It was revealed that the volume around gold nanoparticles where the permittivity is near zero, ε ≈ 0, accounts for the strongest absorption, which leads to the effective enhancements of X-ray emission.
ŠILUMOS SIURBLIŲ INTEGRAVIMO Į ORO RUOŠTUVUS ENERGINĖ ANALIZĖ / ENERGY EFFICIENCY GAIN OF HEAT PUMP INTEGRATION IN AIR HANDLING UNITS
Authors: Čiuprinskas Kęstutis , Šipulskis Vilius
Published: October 2018

This article describes how heat pumps (HP) integrated in air handling units (AHU) proud against the analogous AHU with external heat pumps. Two almost identical (except heat pump position) air handling units were analysed. During the experimental study supply and return air temperatures and AHU’s fans power were measured. Efficiency indicators and consumed energy were calculated based on measured data. Seasonal performance factor (SCOP) and total annual energy use was evaluated for both units. During the economical evaluation was found, that AHU with integrated HP can payback within 10 years compared with AHU combined with external heat pump.

Santrauka

Straipsnyje nagrinėjama, kiek šilumos siurbliai, integruoti į oro ruoštuvus, yra pranašesni už analogiškus išorinius šilumos siurblius. Nagrinėjami du realiomis sąlygomis veikiantys analogiški oro ruoštuvai – vienas su integruotu, o kitas su išoriniu šilumos siurbliu. Tyrimo metu išmatuotos šių įrenginių rodiklių vertės, lemiančios jų energinį naudingumą, tokios kaip oro temperatūra ir vartojama energija. Tam, kad galima būtų nustatyti sezoninį įrenginių efektyvumą (SCOP), šie rodikliai pagal LST EN14825:2016 buvo matuojami esant skirtingai aplinkos temperatūrai. Nustatyti išvestiniai efektyvumo rodikliai bei, remiantis standartu, apskaičiuotas abiejų įrenginių šilumos siurblių efektyvumas. Lyginant pradinių investicijų ir šildymo sezono energijos kaštų skirtumus, įvertintas oro ruoštuvų su integruotais šilumos siurbliais ekonominis naudingumas.
ALTERNATYVIŲ VĖDINIMO SISTEMŲ IR MIKROKLIMATO TYRIMAI GYVENAMAJAME NAME / INVESTIGATION OF ALTERNATIVE VENTILATION SYSTEMS AND INDOOR CLIMATE IN LIVING HOUSE
Authors: Petrašiūnas Rokas , Rogoža Artur , Misevičiūtė Violeta
Published: October 2018

The purpose of the study was to determine which ventilation system centralized or decentralized in viewpoint of economic, energy and comfort is more advantageous in an individual residential house. The relevance of the work is related to the increasing energy efficiency requirements for newly built buildings and the resulting problems of the sick building syndrome due to insufficient ventilation of the rooms. The installation and operation costs of systems were identified. The Life Cycle Analysis (LCA) method was applied to estimate the amount of pollutants and primary energy consumed throughout the lifetime of ventilation systems. Measurements of indoor climate parameters were made; the results compared with the hygiene norms valid in Lithuania. The results of the analysis showed that the decentralized ventilation system is the most advantageous for economic and environmental impacts, but centralized ventilation system ensuring a better indoor climate.

Santrauka

Tyrimo tikslas buvo nustatyti, kokia vėdinimo sistema – centralizuota ar decentralizuota – ekonominiu, energiniu bei komforto požiūriu yra pranašesnė individualiame gyvenamajame name. Darbo aktualumas susijęs su didėjančiais energinio efektyvumo reikalavimais naujai statomiems pastatams ir iš to kylančiomis ligoto pastato sindromo problemomis dėl nepakankamo patalpų vėdinimo. Darbe buvo nustatyti sistemų įrengimo bei eksploatavimo kaštai, pritaikytas gyvavimo ciklo analizės (GCA) metodas, kuriuo įvertinti susidarančių teršalų bei suvartotos pirminės energijos kiekiai per visą vėdinimo sistemų gyvavimo laiką, atlikti patalpų mikroklimato rodiklių matavimai, o gauti rezultatai palyginti su Lietuvoje galiojančiomis higienos normomis. Išanalizavus rezultatus nustatyta, kad ekonominiu ir poveikio aplinkai požiūriais pranašesnė yra decentralizuota vėdinimo sistema, tačiau geresnį patalpų mikroklimatą užtikrina centralizuota vėdinimo sistema.
MINERALINIŲ MEDŽIAGŲ MECHANINIŲ SAVYBIŲ TYRIMAI, ANALIZĖ IR VERTINIMAS / RESEARCH, ANALYSIS, AND EVALUATION OF MECHANICAL PROPERTIES OF AGGREGATES
Authors: Šneideraitienė Lina , Žilionienė Daiva
Published: October 2018

The two Baltic countries, Lithuania and Latvia, use asphalt mixtures with granite slag that is imported from other countries to install the top layer of asphalt pavement, which is quite expensive. One of the requirements for aggregates used in road construction is mechanical properties. There are some differences between these countries based on national requirements. The article presents test methods for determining the mechanical properties of aggregates. According to them, the mechanical properties of aggregates were tested: resistance to fragmentation, wear, polishing and to wear by abrasion from studded tyre. Tested aggregates were Lithuanian dolomite quarry stone, which was made based on the developed and common technologies as well as imported granite from Ukraine. The analysis and evaluation of the test results have been carried out by the requirements for mineral aggregates of Lithuania and Latvia.

Santrauka

Dvi Baltijos šalys, Lietuva ir Latvija, asfalto dangos viršutiniam sluoksniui įrengti naudoja asfalto mišinius su granito skalda, kuri importuojama iš kitų šalių, o tai gana brangu. Vienas iš reikalavimų mineralinėms medžiagoms, naudojamoms kelių tiesyboje, yra mechaninės savybės. Jos minėtose šalyse pagal nacionalinius normatyvinius reikalavimus šiek tiek skiriasi. Straipsnyje pateikti mineralinių medžiagų mechaninių savybių nustatymo bandymo metodų aprašai. Pagal juos atlikti skaldų mechaninių savybių bandymai: atsparumas smūgiams, trupinimui, dėvėjimuisi, poliruojamumui (LST EN 1097-8:2009. Bandymai užpildų mechaninėms ir fizikinėms savybėms nustatyti. 8 dalis. Akmens poliruojamumo nustatymas) bei dygliuotoms padangoms. Ištirtos skaldos yra Lietuvos dolomito karjero skalda, pagaminta pagal patobulintą ir įprastą technologijas, bei granito skalda iš Ukrainos. Atlikta gautų bandymų rezultatų analizė bei vertinimas pagal Lietuvos ir Latvijos reikalavimus mineralinėms medžiagoms.
INDICATORS OF SERVICE QUALITY OF PUBLIC TRANSPORT / VIEŠOJO TRANSPORTO PASLAUGŲ KOKYBĖS RODIKLIAI
Authors: Vabuolytė Vaida , Ušpalytė-Vitkūnienė Rasa
Published: October 2018

This article presents the findings in the field of public transport planning, routes network optimization and service demand affecting indicators as well as analysis of public transport indicators in Klaipėda City. It investigates a wide range of approaches to the evaluation process of service quality of public transport proposed by scientists and these field practitioners and defines the most significant indicators. The article encourages discussions for further research of defined indicators of public transport service and proposes its ranking from the most significant one. Findings are suggested being used for policymakers, planners or other researchers as the base for the evaluation of public transport service network in cities, also to evaluate the quality and compare the results among transport districts within the city limits. By knowing the core of the problem of the network of public transport service, it is possible to plan the changes and improve the service quality, therefore, ridership of the system.

Santrauka

Šiame straipsnyje pristatyti viešojo transporto planavimui, maršrutų tinklo optimizavimui bei šios paslaugos poreikiui įtakos turintys veiksniai (rodikliai) ir taip pat viešojo transporto veiksnių (rodiklių) analizė Klaipėdos mieste. Jame nagrinėtas įvairių mokslininkų ir šios srities specialistų požiūris į viešojo transporto paslaugų kokybės vertinimą ir išskirti svarbiausi rodikliai. Straipsnyje skatinama diskusija dėl tolesnio viešojo transporto rodiklių tyrimo ir siūloma juos įvertinti pagal svarbumą. Siūloma, kad politikos formuotojai, planuotojai ar kiti tyrėjai rodiklius taikytų kaip pagrindą viešojo transporto paslaugų tinklui vertinti miestuose, taip pat įvertintų tinklo kokybę ir palygintų rezultatus tarp miesto transportinių rajonų. Nustačius viešojo transporto tinklo problemas, galima planuoti pokyčius ir pagerinti paslaugų kokybę, kartu padidinant sistemos naudojimą.
Stellar Radiation Is Critical for Regulating Star Formation and Driving Outflows in Low-mass Dwarf Galaxies
Authors: Emerick Andrew , Bryan Greg L. , Mac Low Mordecai-Mark
Published: October 2018

Effective stellar feedback is used in models of galaxy formation to drive realistic galaxy evolution. Models typically include energy injection from supernovae (SNe) as the dominant form of stellar feedback, often in some form of sub-grid recipe. However, it has been recently suggested that pre-SN feedback (stellar winds or radiation) is necessary in high-resolution simulations of galaxy evolution to properly regulate star formation and properties of the interstellar medium (ISM). Following these processes is computationally challenging, so many prescriptions model this feedback approximately, accounting for the local destruction of dense gas clouds around newly formed stars in lieu of a full radiative transfer calculation. In this Letter we examine high-resolution simulations (1.8 pc) of an isolated dwarf galaxy with detailed stellar feedback tracked on a star-by-star basis. By following stellar ionizing radiation with an adaptive ray-tracing radiative transfer method, we test its importance in regulating star formation and driving outflows in this galaxy. We find that including ionizing radiation reduces the star formation rate (SFR) by over a factor of 5, and is necessary to produce the ISM conditions needed for SNe to drive significant outflows. We find that a localized approximation for radiation feedback is sufficient to regulate the SFR on short timescales, but does not allow significant outflows. Short- and long-range radiation effects are both important in driving the evolution of our low-metallicity, low-mass dwarf galaxy. Generalizing these results to more massive galaxies would be a valuable avenue of future research.
Thesium nautimontanum, a new species of Thesiaceae (Santalales) from South Africa
Authors: García Miguel Angel , Nickrent Daniel L. , Mucina Ladislav
Published: October 2018

ThesiumnautimontanumM.A. García, Nickrent & Mucina, a new species from the Matroosberg Mt. of Western Cape Province of South Africa, is described and illustrated. This species shows several morphological features unusual for the genus including stem sympodial branching, indeterminate spicate inflorescences subtended by numerous bracts and fleshy, non-trichome tissue lining the inside of the corolla lobes. Molecular phylogenetic analyses using nuclear ribosomal internal transcribed spacer sequences place this taxon as sister to all African, Madagascan and South AmericanThesiumspecies. Given that only two proximal populations are known, this species is of conservation concern.
An Improved Principal Component Analysis in the Fault Detection of Multi-sensor System of Mobile Robot
Authors: Zhou Zhaihe , Zhang Qianyun , Zhao Qingtao , Chen Ruyi , Zeng Qingxi
Published: October 2018

To cope with the fault detection in dynamic conditions of inertial components in the mobile robots, an improved principal component analysis (PCA) method was proposed. This work took a five gyroscopes redundancy allocation model to realize the measurement of the attitude. It is hard to distinguish the fault message from dynamic message in dynamic system that results in false alarm and missing inspection, so we firstly used the parity vector to preprocess the measurement data from the sensors. A fault was detected when the preprocessed data was dealt with PCA method. The effectiveness of the improved PCA method introduced in this paper was verified by comparing fault detection capabilities of conventional PCA method under the dynamic conditions of the step fault. The results of the simulation and experimental verification of the method was expected to contribute to the fault detection and improve the accuracy and reliability of the multi-sensors system in dynamic conditions.
An Intrusion Detection Model Based On Danger Theory for Wireless Sensor Networks
Authors: Li Linlin , Sun Liangxu , Wang Gang
Published: October 2018

This paper, due to the intrusion detection problem in Wireless Sensor Networks, proposes an intrusion detection model based on the Danger Theory instead of the traditional Self-NonSelf theory. The intrusion detection model has two layers structure including danger perception and control decision, and it uses a multi-node cooperation mechanism. The perception node can realize the danger perception with Projection Pursuit Algorithm, and the decision node can detect the intrusion in detail with Extreme Learning Machine Algorithm. The logic process between their layers is consistent with the Danger Theory. The proposed model can realize the data trust between nodes with the Beta distribution trust evaluation method. By the simulations in the MATLAB, the proposed intrusion detection model on the whole is better than the SNS model at the aspects including classification training, danger perception, false negative rate, false positive rate and energy consumption.
Design of Measurement Memory System Based on MEMS Acceleration Sensor
Authors: Xu Lei , Fang Liqing , Li Xu , Huo Ruikun , Qi Ziyuan , Guo Deqing
Published: October 2018

With the rapid development of MEMS technology, MEMS acceleration sensors have been used more and more widely due to their unique advantages. Taking MEMS acceleration sensor as the core device, a measurement memory system was designed. The system mainly included acceleration detection module, acceleration memory module and control display module, which could realize real-time acceleration measurement and memory, and uploaded the stored data to the computer. Using the vibration test to detect the performance of the system, the result showed that the  system could achieve the desired effect, and could realize real-time acceleration measurement and memory within the allowable  error range. It could still work normally under the condition of the maximum overload of at least 100g, which possessed strong resistance to high overload capacity
Spectrum Sensing for Cognitive Radio Using Genetic Algorithm
Authors: Kochhar Shewangi , Garg Roopali
Published: October 2018

Cognitive Radio has been skillful technology to improve the spectrum sensing as it enables Cognitive Radio to find Primary User (PU) and let secondary User (SU) to utilize the spectrum holes. However detection of PU leads to longer sensing time and interference. Spectrum sensing is done in specific “time frame” and it is further divided into Sensing time and transmission time. Higher the sensing time better will be detection and lesser will be the probability of false alarm. So optimization technique is highly required to address the issue of trade-off between sensing time and throughput. This paper proposed an application of Genetic Algorithm technique for spectrum sensing in cognitive radio. Here results shows that ROC curve of GA is better than PSO in terms of normalized throughput and sensing time. The parameters that are evaluated are throughput, probability of false alarm, sensing time, cost and iteration.
Persistence-Based Area Prioritization for Conservation: Applying Occupancy and Habitat Threats and Risks Analyses
Authors: Yirka Liani M. , Collazo Jaime A. , Williams Steven G. , Cobb David T.
Published: October 2018

Effective habitat conservation is predicated on maintaining high levels or increasing local persistence probability of the species it purports to protect. Thus, methodological approaches that improve the inferential value of local persistence are of utmost value to guide conservation planning as they inform area selection processes. Herein we used the painted bunting Passerina ciris, a species of conservation interest in North Carolina, as an illustrative case that combined single-season, single-species occupancy analyses and a threats and risk decision support tool to rank five areas of conservation interest in terms of local persistence probability. We used survey data from two seasons (2008–2009) grouped into 21 natal dispersal sampling units and land-cover data from 12 habitat classes to establish the relationship between local occupancy probability and habitat. Occupancy increased most strongly with increasing amount of maritime forest. Projections to year 2050, relative to year 2000, indicated that a potential loss of maritime forest of 200–1,300 ha, depending on the area of interest. Projected loss was lowest at Bald Head Island–Wilmington (2%) and highest at Camp Lejune (27%). Bald Head Island–Wilmington ranked highest in projected local persistence probability (0.91; 95% confidence interval [CI] = 0.53–0.99), whereas Top Sail–Hammocks Beach Park ranked lowest (0.28; 95% CI = 0.03–0.82). Estimates of local persistence offer decision-makers another criterion to prioritize areas for conservation and help guide efforts aimed at maintaining or enhancing local persistence. These include in situ habitat management, expanding or connecting existing areas of interest. In the future, we recommend the use of multiseason occupancy models, coupled with measures of uncertainty of land-cover projections, to strengthen inferences about local persistence, particularly useful in nonstationary landscapes driven by human activities.
Educação a distância e ensino profissionalizante: um olhar sobre o acompanhamento do egresso
Authors: Moura Janete Márcia Morais Oliveira , Albuquerque José De Lima
Published: October 2018

A Educação a Distância democratiza o ensino profissionalizante pela inserção de profissionais no mercado de trabalho. Este trabalho objetivou investigar o acompanhamento dos egressos como instrumento de gestão educacional para avaliação da formação profissional. Constitui um estudo de caso com abordagem quali-quantitativa, no qual se utilizou um questionário on-line aplicado junto a egressos dos cursos técnicos de Segurança no Trabalho, Meio Ambiente e Eventos oferecidos na modalidade EAD pelo Instituto Federal de Educação, Ciência e Tecnologia do Piauí, e entrevista com gestores dessa instituição. Saliente-se que, embora não despreze os demais conceitos atribuídos ao termo, este estudo adota, como lastro teórico, a concepção de egresso apresentada por Lousada e Martins (2005), segundo os quais é o aluno oficialmente diplomado que integralizou a matriz curricular do curso e encontra-se apto a inserir-se no mercado de trabalho. Os resultados revelaram que não há um acompanhamento sistemático dos egressos que viabilize à instituição apropriar-se de indicadores acerca da efetividade dos cursos; e que a gestão do egresso é imprescindível por viabilizar o feedback da formação oferecida, dos indicadores de inserção profissional e para uma célere e permanente comunicação entre instituição formadora, egressos e mercado de trabalho.
Influence of the Accuracy of Determining the Inner Diameter of Pressure Polyethylene Pipes by the Amount of Head Loss by Length
Authors: Vasilyeva Maria A.
Published: October 2018

The article presents the results of the analysis of the requirements of All Union State standard No18599-2001 to the thickness of the walls of pressure polyethylene pipes. An example of hydraulic calculation of a pipeline made of polyethylene PE 100 with a diameter d = 315 mm is considered. It is made in two versions - without taking into account and with allowance for dimensional tolerances stipulated by the requirements of the standard. The influence of the limitations on the thickness of the pipe walls on the values of their internal diameters and hydraulic characteristics is analyzed.
Method for Parameter Determination of Ceramic Products Compression Using the Mounting for Curves Readout
Authors: Fomina O.A. , Stolboushkin Andrey Yu. , Druzhinin Mikhail
Published: October 2018

There are given technological factors of pressing of products from ceramic powders. The pressing process is represented as a functional dependence with a set of variables. Four stages of ceramic powders pressing have been found. The method on determination of the pressing parameters of ceramic products using the mounting for curves readout has been shown. Sediment of press powders from clay raw material is determined at different humidity and pressing pressure. The dependence of the physical and mechanical properties of ceramic samples on the humidity content of clay powder and the pressure of raw pressing is established. Compacting pressure values have been found by compression curve when plastic deformation ends and elastic deformations of powder grains start, which corresponds to a translation from the second to the third stage of the pressing process. Areas of rapid deceleration of sagging are in line with the point of the tangent to this curve in the translation from the third to the fourth compression stage have been found. The optimal values of semidry pressing of a ceramic brick have been defined.
Nano Modified Foam-Fiber-Concrete Mixture
Authors: Perfilov V.A. , Gabova V.V.
Published: October 2018

The article describes new compositions of foam-fiber-concrete mixture including portland cement, fine aggregate in the form of quartz sand, glass fiber, hollow glass microspheres, nanoadditives, foam generating agent and superplasticizing agent. The authors offer a technology for preparation of the mixture and determine the physical and mechanic properties of the hardened foam-fiber concrete. The obtained mixtures of foam materials have better compressive and extension strength with increased strength-density ratio as compared to analogous known mixtures of foam-fiber concrete.
The Processing of Citrogypsum for Obtaining Modified Gypsum Binders and Composite Materials on their Basis
Authors: Starostina Yu.L. , Denisova L.V. , Porozhnyuk L.A.
Published: October 2018

The article considers a method of recycling citrogypsum – the сіtric acid production waste. A modified gypsum binder was obtained by means of dehydration of citrogypsum suspension and adding a modifier - polyacrylamide (PAA) - to it in conditions of autoclave treatment. The application of PAA as a modifying admixture causes the necessity to reduce the water-gypsum ratio (W/G) of the mix in order to prevent lamination at the molding product forming; at the same time, to provide the necessary flowability of the mix the introduction of plasticizing admixtures is needed, or the application of the harsher moulding mixtures or pressing technologies. For cylindrical samples, obtained by the compaction method at W/G=0.25 and the specific compacting pressure 20МPа, the optimal content of polyacrylamide as a modifying admixture amounts to 2% of the initial citrogypsum weight. This allows increasing the compression strength of the ready samples by more than 5 times. The samples, produced on the basis of modified gypsum binders, are characterized with high water resistance – the softening coefficient amounted to over 0.8.
The Research of the Influence of Ferruginous Aggregates’ Surface and Polyfunctional Modifiers on Interfacial Phenomena and Strength Formation of the Contact Area in Concretes
Authors: Kosukhin Mikhail M. , Kosukhin Andrei M.
Published: October 2018

The findings of the research concerning the strengthening of the contact area between the cement stone and aggregate, the influence of its surface’s mineral composition and of the interfacial phenomena on the contact area strength formation and the properties of the concrete matrix volume have been summarized. The opportunity of regulating interfacial phenomena and, consequently, the properties of the concrete itself and the strength of its contact area by means of polyfunctional chemical admixtures have been demonstrated. The findings of studying the new efficient polyfunctional modifiers’ influence on the strength formation of the contact area between the cement stone and ferriferrous aggregates and their influence on interfacial processes, occurring at its formation, are presented.
X-Ray Phase Analysis of High-Aluminate Cements under Conditions of early Compression
Authors: Galkin Yu.Yu. , Udodov S.A.
Published: October 2018

Study of the structure of cementitious composites under conditions of early-age compression is essential for development of measures to improve their response to mechanical and physical impact at the earliest stage of hardening. The article considers the influence of early-age compression on the structure of high-aluminate cement which has been studied using X-ray phase analysis. Concrete mixes with different water-cement ratio have been designated as targets for research. It has been established that the age of the cement to the moment of load application impacts on composition of formed hydrates, as well as on amorphousness of the structure of high-alumina cement stone. Compression at a very early age leads to an increase in the number of peaks related to hexagonal hydroaluminates and aluminum hydroxide. Load impact results in various recrystallization behaviors. Transformation of hexagonal hydroaluminates into cubical ones is proceeding faster with growth of water-cement ratio in the samples under compression. This is illustrated by an increase of a number of related peaks in X-ray patterns. Notation: C=CaO; A=Al2O3; H=H2O; S=SiO2; M=MgO.
Increase of Wear Resistance and Contact-Fatigue Strength of Wheel Steel by Plasma Hardening
Authors: Kanayev A.T. , Bogomolov Alexey V. , Kanayev A.A.
Published: October 2018

Metallographic studies of structural-phase states formed in the section of the flange of the wheel band during surface plasma hardening were conducted. It is shown that the formation of several structural zones of different micro hardness is distinctly observed in the depth of hardening, which indicates the formation of a graded-layered structure. It has been confirmed that at superfast heating rates that occur during surface plasma quenching, phase and structural transformations are shifted to high temperatures, greatly changing the kinetics of nucleation and growth of the new phase (austenite). This forms a fine-grained austenite, which turns into a highly disperse martensitic structure, unattainable by traditional methods of heat treatment. It is shown that the main factor leading to strong hardening of the surface layer during plasma treatment is the formation in the near-surface zone of a nonequilibrium metastable structure, which goes over to a narrow zone of complete and incomplete quenching with an inhomogeneous and distorted structure of highly disperse martensite with a high level of internal stresses. The complete wear of the unstressed flange of the tire wheel band is 1.9 mm in 1.1 years, and for hardened flanges, wear is 0.7 mm for 2.6 years.
Increasing the Abrasive Wear Resistance of High-Chromium Steel after Cold Treatment
Authors: Filippov Mikhail A. , Ozerets N. , Nikiforova S.M. , Smagireva E.
Published: October 2018

Ways to increase the abrasive wear resistance of high-chromium steel depending on changes in the temperature of heating for quenching and cold treatment are studied in this paper. It was found that during quenching from temperatures of 850-1000 °C, martensite is formed in the structure of steel H12МFL, which provides high hardness: however, maximum abrasion resistance is not achieved in conditions of abrasive wear. An increase in the heating temperature for quenching to 1170 °C leads to a decrease in the initial hardness, which is due to the dissolution of carbides and an increase in the amount of residual austenite, but this is accompanied by a significant increase in wear resistance in abrasive wear. Residual austenite, obtained as a result of high-temperature hardening (from 1170 °C), is metastable and, in the process of wear, becomes a deformation-induced martensite. This gives the steel maximum wear resistance due to its high frictional hardening ability. A further increase in the temperature of heating for quenching above 1170 °C is inexpedient, since it leads to grain growth. Additional possibilities for increasing abrasive wear resistance consist of the cold treatment of high-carbon steels because of an increase in the amount of cooled martensite and an increase in the initial hardness. Cold treatment of the test steel after high-temperature quenching with cooling to minus 70 °C for 20 min and low tempering at a temperature of 200 °C for 2 h allows for further increases to the abrasion resistance by 25% due to the formation of 15% high-carbon chromic martensite cooling and initial hardness up to 60 НRC, with the preservation of 20% of residual metastable austenite and carbides.
The Use of Metastable Austenite to Increase the Wear Resistance of Steels of the Pearlite Class
Authors: Filippov Mikhail A. , Yagudin G. , Legchilo V. , Khadiyev M. , Ozerets N. , Estemirova Svetlana Kh.
Published: October 2018

The wide application of steel 110G13L for armor plates in mills and crushers makes it urgent to search for alternative materials with close or sufficient operational stability in conditions of shock abrasive wear. A promising path in this direction is the replacement of steel 110G13L with high-carbon pearlitic steels. The aim of this work is a comparative study of the relationship between the structure formed in the heat treatment process of the low-alloyed pearlite steels 70X2GSML and 150HNML and their abrasive wear resistance. Special attention was paid to the possibility of using metastable austenite as a structural component, which increases the abrasive wear resistance of pearlitic steels. It is established that the steel of the pearlite class 70X2GSML, after normalization from 850 °C and tempering at 550 °C, can be used for casting armor plates for ball and rod mills, as well as to cast parts subjected to machining and operating under abrasive conditions without significant impact loads. It is shown that an additional reserve for increasing the abrasive wear resistance of steels of the pearlite class - 70X2GSML and 150XNML - is high-temperature quenching with the formation of a metastable austenite in the structure. The maximum abrasion wear resistance is achieved after the high-temperature quenching of steels (1150 °C) in oil, which forms a martensitic structure with a metastable austenite in the amount of 20-70%, which, with wear, turns into martensite with a high friction hardening ability on the wear surface.
Engineering Method for Analysis of the Ability to Strain-Hardening of Steels
Authors: Filippov Mikhail A. , Korzunova Elena I. , Tyumkova M.V.
Published: October 2018

A study of the structure and strain-hardening ability relationship was carried out in this work for wear-resistant steels of two structural classes: high-manganese austenitic steel 110G13L and metastable austenitic chromium-manganese steel 60G9KhL. It is shown that the strain-hardening ability can be estimated using a methodologically simple engineering criterion. The criterion determines the metal tendency to harden by determining the Rockwell hardness at the bottom of the indentation cup of the Brinell press indenter
Influence of the Parameters of Galvanomechanical Chromium Plating on the Coating Quality and Process Productivity
Authors: Gruba Oksana N. , Shmidt Irina V. , Gorodkova Anastasia E.
Published: October 2018

The article deals with the method of obtaining a hard chromium coating with using abrasive tool. The influence of the pressing force of the abrasive tool, the rotation speed of the part, the temperature of the electrolyte on the results of galvanomechanical chromium plating of rotating cylindrical parts has been studied. A special abrasive tool has been developed for use in the galvanic mechanical coating of metal parts. The tool is made on a polymer bond. The effect of the electrolyte temperature on the quality of the precipitated chromium is revealed.
Investigation of the Influence of Various Kinds of Hardening on the Surface Structure EI893
Authors: Krutsilo V. , Samboruk A. , Krotinov N.
Published: October 2018

The paper presents data on investigation of the microstructure of the surface of EI893 alloy samples on a Jeol JSM-6390A scanning electron microscope after different types of processing: annealing, thermoplastic hardening and surface plastic deformation. The change of structure and thickness of the hardened layer is shown, depending on the type of surface treatment
Ion-Plasma Sprayed Coating as a Protective Decorative Coating for Copper-Nickel Alloy
Authors: Baraz Vladislav R. , Gerasimov S.S. , Gruzdeva Irina A.
Published: October 2018

This article is devoted to studiing the ion-plasma sprayed coating on the surface of copper-nickel alloy obtained by complex titanium nitride and zirconium nitride treatment. To evaluate the coating microhardness we use the method that provides the obligatory penetration of diamond-pointed pyramid through nitride layer. It is shown that nitride coating microhardness is much higher than the copper-nickel alloy microhardness. Furthermore, surface treatment provides the color of the nitride coating just as gold plated.
Layered Ni-Cr-Al Coatings for Air Tuyeres Protection from the Burnout
Authors: Shmorgun Victor Georgievich , Bogdanov Artem I. , Taube Aleksandr O.
Published: October 2018

A technological scheme for obtaining of the protective layered coating of the Ni-Cr-Al system on the surface of copper parts is proposed. Deformation of the explosion welded composite material copper substrate M1 + alloy Cr20Ni80 + aluminum AD1 in the process of the cold pressing of the tuyere nose was simulated in the SIMULIA/Abaqus software and the temperature distribution over the profile of the three-layer wall M1-Cr20Ni80-coating under the conditions of the process stabilization at background temperature 1600°С was simulated in the DEFORM-2D software.
New Technology of Hardening of Chromium-Nickel Steel Parts
Authors: Astashchenko V.I. , Purtova E.V.
Published: October 2018

The structure and properties of the cemented products from steel 20H2N4A strengthened according to different schemes of chemical heat treatment is investigated. The reason of low static and cyclic firmness of parts is established. The new technology of hardening of parts which is based on application of low-temperature cementation is developed and offered. For a steel saturation process of intensification with carbon it is recommended to increase the content of hydrogen to 40% in the endoatmosphere and to enter a small amount of ammonia into the saturating atmosphere of the furnace.
New Decisions in Manufacturing Techniques of the Cemented Parts of Cars
Authors: Shveyova T.V. , Astashchenko V.I. , Shveyov A.I.
Published: October 2018

The unused reserves of metal and manufacturing techniques of forgings and hardening of products promoting minimization and stabilization of deformation and a buckling of gear details are revealed. Need of rationing of size of a hardenability of steel, a regulation of speed of cooling of forgings after hot stamping and application of isothermal annealing as preliminary heat treatment is established. The rational scheme of laying and technology of low-temperature cementation of pinion gears providing the minimum change of the geometrical sizes of details in chemical and thermal processes is offered.
Numerical Solution of the Differential Diffusion Equation for a Steel Carburizing Process
Authors: Maisuradze Mikhail V. , Kuklina Alexandra A.
Published: October 2018

The simplified algorithm of the numerical solution of the differential diffusion equation is presented. The solution is based on the one-dimensional diffusion model with the third kind boundary conditions and the finite difference method. The proposed approach allows for the quick and precise assessment of the carburizing process parameters – temperature and time.
Using VPr11-40N Brazing Powder as a Wear-Resistant Cladding for GTE Blade Airfoils
Authors: Klimov V.G. , Zhatkin Sergey S. , Kogteva A.V.
Published: October 2018

This paper dwells upon using the VPr11-40N high-temperature brazing powder as a cladding applied by a laser to restore the height of the airfoil of a turbostarter blade in an NK-12MP turboprop, while also making the edge more wear-resistant. It has been found out that laser cladding generates a highly homogeneous structure with lesser gradient of hardness over the clad area compared to furnace brazing. Abrasive-wear tests have shown that this braze resists abrasive wear better than the blade substrate material (superalloy JS6К heat-resistant intermetallic alloy).
Investigation of the Hydrogen Stratification of the Metal of the Active Gas Pipeline
Authors: Nasibullina O.A. , Gareev A.G. , Rizvanov Rif G.
Published: October 2018

One of the most common types of metal destruction in the oil and gas industry is hydrogen embrittlement. Hydrogen corrosion is a complex of negative effects of hydrogen on steel, leading to the destruction of metal structures. Hydrogen passes through a defect-free metal, without lingering in it. In the presence of defects, hydrogen is retained in the metal forming a brittle solid solution, metal stratification along the segregation streamer, blistering. Studies of the metal of a gas pipeline made of steel 09G2S are presented in the article. The sample was selected from the local zone of destruction in the condensate collector, the metal of the pipe had typical for hydrogen corrosion stratifications. The scope of the study was identification of the most dangerous part of hydrogen corrosion on the sample taken from the local zone of destruction. Studies on the chemical composition and mechanical properties of 09G2S steel were also carried out. Stress-related characteristics of the metal microstructure of the failed gas pipeline were obtained and the character of the destruction progress was revealed. The presence of sulfides cluster in the metal of studied pipe was determined applying metallographic method for determining nonmetallic inclusions.
Experimental Study of the Effectiveness of the Vibromechanical Stabilization of Bearing Rings
Authors: Korolev Albert Viktorovich , Balaev A.F. , Korolev A.A.
Published: October 2018

The paper provides the comparison of vibromechanical technology for stabilization of bearing rings and thermal tempering on the following parameters: performance, energy consumption, and magnitude of residual stresses after treatment. To assess the effectiveness of residual stress relaxation through the usage of vibromechanical energy, there were conducted experimental studies on a specially designed and manufactured prototype of the equipment. The results of experimental studies show that the energy consumption during vibromechanical stabilization is ten times less, and performance is several times higher than during the thermal tempering. Moreover, vibromechanical stabilization allows more effective residual stresses relaxation. The costs for capital investment can be reduced, as the cost of equipment for vibromechanical stabilization is ten times less than the cost of electric furnaces.