724 research outputs found
Cutting-edge industrial technology of mining tool manufacturing
Purpose. To conduct a comparative economic analysis of cermet alloys regeneration technology, to identify the most “environmentally friendly” and cost-effective processing of solid alloys waste.
Methods. As a research technique, the present article considers analysis of current methods of solid tungsten cobalt alloys regeneration: pyro and hydro metallurgical, chemical (chlorine, zinc), thermochemical and the method which uses energy of blasting explosives.
Findings. A comparative economic analysis of cermet alloys regeneration technologies was conducted.
Originality. Fundamental way of shock wave treatment to stimulate destruction of powder product of any configuration in order to obtain a high quality powder for further formation, sintering and tool manufacturing of multiple use is demonstrated; ecologically friendly technology of hard alloys and cermet components of outdated military hardware and ammunition recycling has been developed.
Practical implications. Industrial implementation of the developed technology allows to solve the following issues:
– utilizing super hard metal and alloys scrap for subsequent regeneration, which ensures significant savings of strategic raw material;
– the use of new technology, which excludes ineffective ways of scarce raw materials processing and manufacturing products satisfying international standards;
– gradual reduction of import in favor of hard alloys cermet tools;
– reduction and subsequent abandonment of strategic metals and alloys scrap export, shifting towards the export of ready products – powders and tools, which will significantly increase foreign currency earnings in the country.Мета. Провести порівняльний економічний аналіз технологій регенерації металокерамічних сплавів і вибрати найбільш “екологічно чисту” та рентабельну технологію переробки відходів твердих сплавів.
Методика. В якості методики дослідження для представленої роботи було проаналізовано кілька існуючих методів регенерації відходів вольфрамом кобальтових твердих сплавів: піро- й гідрометалургійний, хімічний (хлорний, цинковий), термохімічний та із застосуванням енергії вибуху бризантних вибухових речовин.
Результати. Проведено порівняльний економічний аналіз технологій регенерації металокерамічних сплавів.
Наукова новизна. Показана принципова можливість використання ударно-хвильової обробки як фактора, що стимулює процеси руйнування порошкових виробів будь-якої конфігурації, з метою отримання високоякісного порошку для подальшого формування, спікання й виробництва інструменту різного призначення; запропоновано екологічно чисту технологію переробки надтвердих матеріалів, металокерамічних складових застарілої військової техніки та різних видів боєприпасів.
Практична значимість. Промислове освоєння розробленої технології дозволяє вирішити наступні проблеми:
– утилізацію лому надтвердих матеріалів і сплавів з їх подальшим відновленням і відповідно значною економією стратегічної сировини;
– використання нової технології з виключенням вживання малоефективних способів переробки дефіцитної сировини і випуск продукції світового рівня якості;
– поступова відмова від імпорту у бік твердосплавного металокерамічного інструменту;
– зменшення, а потім і відмова, від експорту за межі України лому стратегічних матеріалів і сплавів, з переходом до експорту готових виробів-порошків та інструменту, що значно збільшить валютні надходження в країну.Цель. Провести сравнительный экономический анализ технологий регенерации металлокерамических сплавов и выбрать наиболее “экологически чистую” и рентабельную технологию переработки отходов твердых сплавов.
Методика. В качестве методики исследования в настоящей работе были проанализированы несколько существующих методов регенерации отходов вольфрамом кобальтовых твердых сплавов: пиро- и гидрометаллургический, химический (хлорный, цинковый), термохимический и с применением энергии взрыва бризантных взрывчатых веществ.
Результаты. Проведен сравнительный экономический анализ технологий регенерации металлокерамических сплавов.
Научная новизна. Показана принципиальная возможность использования ударно-волновой обработки как фактора, стимулирующего процессы разрушения порошковых изделий любой конфигурации, с целью получения высококачественного порошка для дальнейшей формовки, спекания и производства инструмента различного назначения; предложена экологически чистая технология переработки сверхтвердых материалов, металлокерамических составляющих устаревшей военной техники и различных видов боеприпасов.
Практическая значимость. Промышленное освоение разработанной технологии позволяет решить следующие проблемы:
– утилизацию лома сверхтвердых материалов и сплавов с их последующим восстановлением и соответственно значительной экономией стратегического сырья;
– использование новой технологии с исключением употребления малоэффективных способов переработки дефицитного сырья и выпуск продукции мирового уровня качества;
– постепенный отказ от импорта в сторону твердосплавного металлокерамического инструмента;
– уменьшение, а затем и отказ, от экспорта за пределы Украины лома стратегических материалов и сплавов, с переходом к экспорту готовых изделий – порошков и инструмента, что значительно увеличит валютные поступления в страну.Scientific work is done in the framework of complex special purpose program “Organizing collection, utilization and recycling processes of hard alloys containing tungsten, tungsten scrap, molybdenum, cobalt and their alloys”.
The authors extend their thanks to Rostyslav Didyk, Professor with the Department of Mining Engineering of the National Mining University
Quantum geometrodynamics of the Bianchi IX model in extended phase space
A way of constructing mathematically correct quantum geometrodynamics of a
closed universe is presented. The resulting theory appears to be
gauge-noninvariant and thus consistent with the observation conditions of a
closed universe, by that being considerably distinguished from the conventional
Wheeler - DeWitt one. For the Bianchi-IX cosmological model it is shown that a
normalizable wave function of the Universe depends on time, allows the standard
probability interpretation and satisfies a gauge-noninvariant dynamical
Schrodinger equation. The Wheeler - DeWitt quantum geometrodynamics is
represented by a singular, BRST-invariant solution to the Schrodinger equation
having no property of normalizability.Comment: LaTeX, 18 pages, to be published in Int. J. Mod. Phys.
Determination Methods of Food Fibers Characteristics in Milk Mixtures with the Modified Fat Composition
The article presents main determination methods of technological parameters of food fibers in milk mixtures of the modified fat composition.The methods of studying the ability of food fibers to water and fat-absorption are offered. The values that characterize swelling parameters of vegetable ingredients in experimental mixtures are obtained.The effectiveness of the method of IR-spectroscopy for indentifying and comparing water-binding forms in mixtures of food fibers with water and butterdish is proved.The indices of thermal stability and degree of liquid fat outflow for mixtures with the modified fat composition with the maximal replacement of cream butter by 25 % of oil are obtained. The research results indicate objective possibilities for the effective use of food fibers Vicetal for stabilizing the structure and preventing consistence defects of products with the modified fat composition
A note on the weak Harnack inequality for unbounded minimizers of elliptic functionals with generalized Orlicz growth
We prove the weak Harnack inequality for the functions which belong to
the corresponding De Giorgi classes under the additional
assumption that with some . In particular, our
result covers new cases of functionals with a variable exponent or double-phase
functionals under the non-logarithmic condition
Importance of serous intraepithelial ovarian tubal carcinomas in the occurrence of "high-grade" serous carcinomas and / or peritoneal serous carcinomas of unknown primary origin.
Studies of the recent decades on serous pelvic adenocarcinomas in women have set the goal of distinguishing between two diagnostic units: "low-grade" and "high-grade" carcinomas. The predecessor of the "low-grade" variant (type I) is considered to be a borderline serous tumor / atypical proliferative serous tumor (8442/1), which according to the International Classification of Diseases for Oncology ICD-O 2013 of the female reproductive system refers to non-specific, borderline tumors and tumors with unpredictable clinical behavior. The predecessors of the “high-grade” variant (type II) are serous tubular intraepithelial carcinomas (in situ) or “high-grade” serous invasive tubal carcinomas, since they have the TP53 mutation identical to “high-grade” ovarian carcinoma, an aberrant p53 protein expression, high proliferative activity, and significant genomic instability. In addition, according to the carcinogenesis of "high-grade" serous ovarian carcinoma with metastases to the peritoneum, it can also be interpreted as "pelvic high-grade serous carcinoma". A retrospective analysis of the histological, morphometric and immunohistochemical characteristics of the biopsy material of 31 women aged from 28 to 76 years (mean 57.32±11.54; median 57), divided into 3 groups, was carried out. Group 1: 14 observations of the tubal epithelium (8 tubes without pathological changes (subgroup 1a) and 6 with signs of intraepithelial neoplasia (subgroup 1b); group 2: 12 cases of serous adenocarcinoma of the ovary of the “high-grade” variant; group 3: 6 metastatic peritoneal serous carcinoma without a known primary site. Results. Group immunophenotypes showed uniformity in the expression of markers CK7 (+, +/-), CK20 (-), WT-1 (+), CA125 (+, +/-), with an affinity to distal uterine tube fragments. The expression of p53 in all groups with signs of carcinomas (compared with the control subgroup 1a without atypia) was divided into two options - negative samples and samples with overexpression, where no statistically significant difference was found (p>0.05), which is possibly a single way of carcinogenesis. The morphometric study revealed a significant difference in the area of the nuclei between group 3 and the first three groups (1a, 1b, 2), which indicates the similarity of ovarian and tubal neoplasias and uterine tube epithelium. The number of intranuclear reactions with ER and PGR progressively decreased from group 1 to group 3, with an increase in cases with ER (+/-) / PGR (+/- or -) to 50% in group 3, which greatly complicated the diagnostic search for unknown carcinomas of primary localization. HER-2-new expression revealed a possible amplification (gradation 2 + / 3 +) only in group 2 at the level of 16.67% and in group 3 at the level of 33.33%
Determination Methods Of Defrosted Protein-vegetable Mixtures Parameters Development
The aim of the work is to develop methods of investigating the influence of semolina and extruded semolina on quality and quantity parameters of mixtures with milk-protein concentrates in a cycle of freezing-defrost that allows to substantiate resource-saving in semi-products manufacturing.Obtained results of changes of the quality of protein-vegetable mixtures after the effect of negative temperatures confirm cryo-protective properties of carbohydrates of products of wheat processing.There were studied methods of extracting proteins of whey for getting albumin mass and using in the composition of milk-protein concentrates. It was established, that adding collagen-containing ingredients in amount 0,4 % for intensifying thermal coagulation of whey proteins decreases the duration of precipitation to (55±2) and (40±2) min respectively depending on a type of raw material processing. There were studied both native whey and protein concentrate, obtained by the method of ultra-filtration with mass share of dry substances (16±2) %.The method of thermal analysis determined a cryoscopic temperature of sour-milk fatless cheese and also albumin mass, obtained using «Collagen pro 4402». The calculation method, based on cryoscopic temperature indices determined an amount of moisture, frozen out in milk-whey mixtures with wheat processing products. The presented information is enough for estimating traditional modes of freezing milk-protein concentrates objectively.The obtained results of the studies indicate the effectiveness of the offered methods for determining parameters of protein-vegetable mixtures after defrosting. Measurements of quality parameters may be used for correcting mass losses of concentrates effectively
Shot Noise in Mesoscopic Transport Through Localised States
We show that shot noise can be used for studies of hopping and resonant
tunnelling between localised electron states. In hopping via several states,
shot noise is seen to be suppressed compared with its classical Poisson value
( is the average current) and the suppression depends on the
distribution of the barriers between the localised states. In resonant
tunnelling through a single impurity an enhancement of shot noise is observed.
It has been established, both theoretically and experimentally, that a
considerable increase of noise occurs due to Coulomb interaction between two
resonant tunnelling channels.Comment: 7 pages, 5 figures; Proceedings of the 10th Conference on Hopping and
Related Phenomena (Trieste 2003); requires Wiley style files (included
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