Experimental Studies of Mechanical Vibration Assisted Induction Heating Hot-Pressing

2014 ◽  
Vol 1021 ◽  
pp. 190-195
Author(s):  
Fei Wu ◽  
Zhao Yao Zhou ◽  
Meng Long Dong ◽  
Bi Bo Yao

A new method of mechanical vibration assisted induction heating hot-pressing was proposed. A set of apparatus was developed to perform the forming of mechanical vibration assisted induction heating hot-pressing. A series of experiments of induction heating temperature characteristics of different kinds of powder was carried out, such as Fe powder, Al powder and SiC powder. The results show that different kinds of powder reach different equilibrium temperatures and have different temperature characteristics under the same condition of setting temperature and cyclic heating times. SiCp/Al composites were prepared by induction heating and vibratory forming and observed by metallographic microscope. It turns out that completely dense and homogeneous powder metallurgy compaction is compacted and sintered at the same time by the method of mechanical vibration assisted induction heating hot-pressing with low pressure and short time.

2010 ◽  
Vol 65 (8) ◽  
pp. 1038-1044 ◽  
Author(s):  
Kazumichi Yanagisawa ◽  
Jae-Hyen Kim ◽  
Chisato Sakata ◽  
Ayumu Onda ◽  
Eri Sasabe ◽  
...  

Calcium-deficient hydroxyapatite (CDHA) prepared by the coprecipitation method was solidified by the hydrothermal hot-pressing technique, and compacts of CDHA with high bulk density beyond 80% were obtained at 200 ℃. Each reaction parameter, viz. reaction temperature, pressure, and time, was systematically changed from the standard conditions to investigate its effects on density, Vickers hardness, and Ca/P ratio of the compacts obtained. The reaction temperature and pressure had a large effect on densification, but not the reaction time because the densification proceeds in a short time. The densification by hydrothermal hot-pressing involved dissolution and precipitation of the starting CDHA powder, so that the Ca/P ratio changed from 1.52 of the starting powders to 1.61 of the compact obtained by hydrothermal hot-pressing at 200 ℃ and 35 MPa for 24 h with the addition of 10 wt.-% water


2019 ◽  
Vol 10 (3) ◽  
pp. 5-15
Author(s):  
M. L Nuzhdin

Often in construction practice there is a need to strengthen the pile foundation of buildings and structures. The traditional methods include the implementation of additional, as a rule, bored piles with the subsequent erection of a grillage incorporating them into operation. Often, this work has to be done in the conditions of dense urban development, in cramped rooms of the basement, etc., which leads to significant technological difficulties. One of the alternative ways to strengthen pile foundations is the method of high-pressure group injection, which consists in injecting a movable cement-sand mortar into the soil under pressure that exceeds its structural strength. As a result, after its hardening, solid injection bodies are formed at the base, reinforcing the soil base. The article describes the results of experiments to assess the impact of the layout of hard inclusions on the deformability of the soil foundation of the pile foundation model. The experiments were carried out in a small soil tray, which was filled with medium-grained loose sand. The piles were modeled with metal rods, the pile grillage with a metal square stamp. The pile foundation model included 9 piles arranged in a square grid. As injection bodies, gravel grains of various sizes and shapes were used. The studies included 10 series of experiments (each experiment was repeated at least 3 times): the volume of the inclusions used, their sizes, the positioning step in the plan and in depth varied. As a result of the analysis of the performed experiments, conclusions were formulated regarding the purpose of the optimal layout of hard inclusions when strengthening the soil foundation of pile foundations by high-pressure injection of mobile cement-sand mixtures.


Author(s):  
V.Yu. Lavrinenko ◽  
Yu.A. Lavrinenko ◽  
R.S. Fayruzov ◽  
A.S. Ayrapetyan ◽  
A.S. Kirsanov

The results of experimental studies of flow curves of 32CrB4, 20G2R and 1.4034 (analogue of 40Kh13 steel) steels at different heating temperature of workpieces are presented. Rational intervals of preliminary lowtemperature heating of workpieces made of studied steels are obtained. It allows to decrease forces during cold forging, loads on the working tool and to increase of tool life time up to 2 times.


2020 ◽  
pp. 87-91
Author(s):  
M. Tymchenko ◽  
Yu. Ivanova ◽  
V. Padalko ◽  
H. Sheremet ◽  
O. Kozlova ◽  
...  

Summary. The aimof the study is to develop a method of sealing the sutured of the small intestine anastomosis in conditions of high risk anastomosis leakege by stopping the inflammation’ cascade in experiment. Materials and methods.The work was experimental in nature, was performed in the SI «ZIGUS NAMSU» in collaboration with the Scientific Research Institute of Biology V. N. Karazin KhNU in the period from 2018 to 2019. To increase the tightness of the intestinal anastomoses applied under conditions of laparatomy, experimental studies were conducted on laboratory animals. The studies were carried out after the permission of the ethics committee SI «ZIGUS NAMSU» in compliance with all ethical requirements for the humane treatment of animals.Surgical operations in two series of experiments were performed under operating conditions under general anesthesia on 10 white sexually mature linear rats – Wistar males, 12-18 months old, weighing about 250 grams. All morphological material (the first and second series of experiments) was marked and fixed in a 10% solution of neutral formalin. Subsequently, paraffin sections were prepared according to the generally accepted histotechnical method and stained with hematoxylin - eosin; according to Van Gieson and Mallory, an immunohistochemical study was used to study microenvironment factors. Results and Discussion. Immunohistochemical examination of the intestine was carried out in several stages, at the first stage we took intestinal tissue during the surgery to form the intestinal anastomosis, before the introduction of allogeneic cell transplants. Also carried out immunohistochemical studies of the emerging mucous membrane at various times after the formation of insolvency of intestinal anastomoses in both studied groups. When using a cell allograft, the mechanisms of repair of the intestinal mucosa include the appearance of cells that carry the expression of markers of mesenchymal and epithelial differentiation (Vim, CD34, CKW, Ecad), and are usually localized in the walls of blood vessels of granulation tissue, as well as in areas of the repairing epithelium. In addition, in the main group, only 7 days after the reaction to cytokeratins (CKW) and Ecad, areas of the repairing epithelium were detected, while the visualization of the epithelium in the control group did not begin even after 10 days. The analysis of immunophenotypes of repairing cells allows us to suggest the participation of mesenchymal-epithelial transformation mechanisms in this process. Conclusions.Thus, studies have shown that the use of cell transplantation of culture of allogeneic cells of the intestine leads to the reconstruction of the intestinal mucosa in a fairly short time. Conducted histological and immunohistochemical studies showed that in the vast majority of animals (77.2%) 10-14 days after the operation, an almost unchanged mucous membrane forms with the preservation of its elasticity.


2020 ◽  
Vol 164 ◽  
pp. 01001
Author(s):  
Alexander Chusov ◽  
Mikhail Shilin ◽  
George Gogoberidze ◽  
Julia Lednova ◽  
Nikolai Bobylev

The goal of the fulfilled research is the study of the influence of the sedimentary suspension from the dredging material on the benthic hydrobionts. In laboratory aquariums six series of experiments were carried out with triple replication on the ability of different benthic organisms to dig out the soil strata due to their periodic burying by marine sand. These experiments were oriented on biota of Eastern Gulf of Finland and the Neva Bay, where a number of deposit sites for dredging material are located presently. Representatives of three main groups of hydrobionts of these areas were selected for experiments – Chironomidae, Gastropoda and Oligochaeta. The ability of different hydrobiont species to overcome the stress effect of the burying under the dredged material was estimated quantitatively. The results show, that the resistance of the studied species to mechanical burying is decreasing in accordance to the scheme: Chironomus plumosus > Melanoides tuberculata > Tubifex tubifex, and depends from the thickness of the layer of dredged material.


1994 ◽  
Vol 76 (1) ◽  
pp. 416-423 ◽  
Author(s):  
M. J. Engwall ◽  
C. A. Smith ◽  
J. A. Dempsey ◽  
G. E. Bisgard

We have previously established the existence of ventilatory afterdischarge (VAD) in the awake goat by means of an isolated perfused carotid body (CB) technique. In the present series of experiments we used this animal preparation to examine the effects of systemic (central nervous system) hypoxia, mild hypercapnia, and hypocapnia on the manifestation of VAD in ventilatory variables and respiratory muscle electromyogram activity after hypoxic stimulation of the isolated CB. With systemic isocapnic normoxia, inspired minute ventilation remains above control for 30–40 s (time constant = 16.8 s) after termination of CB hypoxia; however, with systemic hypocapnia, VAD is short (time constant = 5.5 s) and hypoventilation is common after removal of CB stimulation. During mild systemic hypercapnia, VAD is prolonged (time constant = 39.9 s). However, systemic (central nervous system) hypoxia did not decrease VAD (time constant = 17.0 s). These results indicate that the manifestation of VAD is more sensitive to the level of arterial PCO2 and central chemoreceptor activity than it is to the state of central oxygenation. Inspiratory and expiratory muscle electromyogram activities qualitatively tracked ventilation during CB stimulation and during the VAD period in all conditions.


2020 ◽  
Vol 299 ◽  
pp. 1166-1171 ◽  
Author(s):  
Phyo Wai Aung ◽  
Maryin S. Borisovich

Experimental studies of the influence of the heating temperature on the properties of pipe billets made of titanium alloys OT4 and OT4-1 in the formation of parts for the installation of pipeline systems without a protective atmosphere are presented.


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