scholarly journals Influence of the composition of the boroning mixture on the dimension change of pressed and boroned samples from iron powder

2008 ◽  
Vol 40 (2) ◽  
pp. 197-205
Author(s):  
S. Ivanov ◽  
E. Pozega
Keyword(s):  
Mathematical Modelling ◽  
Iron Powder ◽  
Metal Powder ◽  
Volume Change ◽  
Potassium Fluoride ◽  
Chemical Compositions ◽  
Thermal Treatments ◽  
Volume Changes ◽  
Dimension Change ◽  
Powder Samples

Volume changes occur during sintering and chemical-thermal treatments of metal powder samples. The results of the investigation of the volume change of pressed and boroned samples from an iron powder, depending on the mixture composition used for the boroning process, are presented in this paper. The basic mixture, used for boroning of the investigated samples from iron powder, is modified by the addition of activators with different chemical compositions and in different concentrations, of up to 4 wt %. Mixtures with ammonium bifluoride, ammonium chloride and boron potassium fluoride were investigated. The research results and the mathematical modelling enable the choice of mixture compositions for boroning based on the volume change given in advance.

scholarly journals The possibility of the boronizing process on the pressed samples of iron powder

2009 ◽  
Vol 63 (3) ◽  
pp. 253-258
Author(s):  
Emina Pozega ◽  
Svetlana Ivanov ◽  
Vesna Conic ◽  
Branislav Cadjenovic
Keyword(s):  
Experimental Investigation ◽  
Thermal Treatment ◽  
Iron Powder ◽  
Ammonium Chloride ◽  
Treatment Process ◽  
Polynomial Function ◽  
Potassium Fluoride ◽  
Volume Changes ◽  
Fourth Degree ◽  
Powder Samples

The paper presents results of the experimental investigation of the boronizing process on nonsintering iron powder samples (NC100.24, H?gan?s, Sweden). Experiments are planned within the limits of applicability of simultaneous sintering at chemical-thermal treatment process (boronizing). The simlex plan of 15 experimental points was used for the experiment, while a polynomial function of fourth degree was employed in the modeling of a mixture composition based on the volume changes, porosity and the depth layer changes. Boronizing was carried out in mixture with born carbide by addition of ammonium bifluoride, ammonium chloride and boron potassium fluoride as activators, by proportion definited plan.

Volume Change Associated to Carbon Partitioning from Martensite to Austenite

2012 ◽  
Vol 706-709 ◽  
pp. 2290-2295 ◽  
Author(s):  
M. J. Santofimia ◽  
Lie Zhao ◽  
Jilt Sietsma
Keyword(s):  
Volume Change ◽  
Chemical Potential ◽  
Theoretical Models ◽  
Carbon Partitioning ◽  
Volume Changes ◽  
Measured Volume

Annealing of martensite/austenite microstructures leads to the partitioning of carbon from martensite to austenite until the chemical potential of carbon equilibrates in both phases. This work calculates the volume change associated with this phenomenon using theoretical models for the carbon partitioning from martensite to austenite. Calculations are compared with experimentally determined volume changes. This comparison reveals that in the case of steels with higher contents of austenite-stabilizing elements, reported volume changes are satisfactory predicted assuming a low mobilily martensite/austenite interface. In the case of a steel with lower additions of austenite-stabilizing elements, experimentally measured expansions are considerably larger than predicted ones. The large measured volume expansions probably reflect the decomposition of the austenite.

A New Micro-Respirometer with Automatic Setting and Recording Apparatus

1950 ◽  
Vol 27 (3) ◽  
pp. 334-349
Author(s):  
PETER TUFT
Keyword(s):  
Volume Change ◽  
Constant Pressure ◽  
Volume Changes ◽  
Recording Apparatus

A new micro-respirometer is described, capable of measuring rates of volume change from 5 µl./hr. down to 0.01 µl./hr. to the nearest 0.001 µl. It is a constant-pressure nul-reading instrument and the actual volumes of gas absorbed or evolved are obtained from readings of the instrument by a simple multiplication. A device is described which sets the instrument automatically and records the volume changes at regular intervals.

Pressure response to quick volume changes in tetanized isolated ferret hearts

1989 ◽  
Vol 257 (1) ◽  
pp. H38-H46 ◽  
Author(s):  
K. B. Campbell ◽  
A. R. Rahimi ◽  
D. L. Bell ◽  
R. D. Kirkpatrick ◽  
J. A. Ringo
Keyword(s):  
Cardiac Muscle ◽  
Muscle Fiber ◽  
Volume Change ◽  
Initial Pressure ◽  
Recovery Phase ◽  
Left Ventricular ◽  
Fast Recovery ◽  
Volume Changes ◽  
Slow Recovery ◽  
Length Changes

Observed pressure responses to quick volume changes in the isolated tetanized heart of ferrets were compared with previously reported tension responses to quick length changes in isolated cardiac muscle. Hearts were isolated from ferrets, perfused with ryanodine solution, and stimulated rapidly (50 ms between stimulations) to produce repeated 4-s intervals of tetanus. During each tetanus interval, volume increments of different amplitudes were rapidly removed and then reinfused into the left ventricular chamber. The pressure responses to these volume changes were evaluated for differences between withdrawals and infusions and for dependence on the amplitude of the volume change. It was found for both withdrawal and infusion that the response could be divided into three phases: 1) an immediate phase coincident with volume change, 2) a fast-recovery phase, and 3) a slow-recovery phase. The amplitude of the immediate phase was linearly dependent on the volume change so that a single regression line fit all the data (withdrawal and infusion). The fast recovery phase was 2.5 times faster for infusion than for withdrawal and generated a rebound effect with the pressure going below the initial pressure in the response to infusion. The pressure never went above the initial pressure in the response to withdrawal. The slow-recovery phases in infusion and withdrawal did not differ. These responses in the isolated heart bear striking similarities to tension responses to quick length changes in isolated constantly activated cardiac muscle. We concluded that muscle fiber dynamics were being faithfully transformed to left ventricular (LV) chamber dynamics without appreciable distortion because of the many intervening factors between the wall muscle fiber and the LV chamber.(ABSTRACT TRUNCATED AT 250 WORDS)

Influence of Carburizing Time of Iron Powder Samples on the Carbon Content after Gas-Carburizing - Sintering Process

2018 ◽  
Vol 880 ◽  
pp. 235-240
Author(s):  
Mario Trotea ◽  
Augustin Constantinescu ◽  
Loreta Simniceanu ◽  
Gabriela Monica Pană
Keyword(s):  
Carbon Content ◽  
Iron Powder ◽  
Sintering Process ◽  
Sintered Steel ◽  
Diffusion Analysis ◽  
Gas Carburizing ◽  
Powder Samples ◽  
Sintered Carbon ◽  
Gas Medium ◽  
Sintering Method

The paper presents experimental results of the influence of carburizing time of iron powder samples on the carbon content in the sample’s depth by layers, subjected to a GCS (Gas-Carburizing Sintering) method. Sintered steel elaboration by GCS method consist of enriching the Fe powder with carbon in gas medium in a single thermal cycle including the carburising operation followed by sintering, thereby achieving the sintered carbon steel. Numerical simulations were made using Abaqus/CAE software for mass diffusion analysis in order to find the appropriate diffusion coefficient value.

Photocatalytic Decomposition of Rhodamine-B Using Scandium and Silver-Modified TiO2 Powders

2014 ◽  
Vol 975 ◽  
pp. 213-218 ◽  
Author(s):  
Douglas Washington da Silva ◽  
Daniela Cristina Manfroi ◽  
Guilhermina Ferreira Teixeira ◽  
Leining Antônio Perazolli ◽  
Maria Aparecida Zaghete ◽  
...  
Keyword(s):  
Rhodamine B ◽  
Photocatalytic Oxidation ◽  
Rutile Phase ◽  
Photocatalytic Decomposition ◽  
Metallic Silver ◽  
Thermal Treatments ◽  
Type Semiconductor ◽  
Powder Samples ◽  
P Type ◽  
Hybrid Modification

Semiconductor-mediated photocatalytic oxidation is an interesting method for water decontamination and a specially modified TiO2 is said to be a promising material. This study verified that the synthesis of 1wt%Ag modified-Sc0.01Ti0.99O1.995 powder samples prepared by Polymeric Precursor Method is capable of forming a mixture of anatase-rutile phase with high photocatalytic performance. This kind of material is found to have a lower bandgap compared to the TiO2-anatase commercial powders, which can be associated to an innovative hybrid modification. The simultaneous insertion of scandium in order to generate a p-type semiconductor and a metallic silver nanophase acting as an electron trapper demonstrated being capable of enhancing the degradation of rhodamine B compared to the commercial TiO2. In spite of the different thermal treatments or phase amounts, the hybrid modified powder samples showed higher photocatalytic activity than the commercial ones.

A new simple system for measuring volume changes in unsaturated soils

2002 ◽  
Vol 39 (3) ◽  
pp. 757-764 ◽  
Author(s):  
C W.W Ng ◽  
L T Zhan ◽  
Y J Cui
Keyword(s):  
Volume Change ◽  
Unsaturated Soils ◽  
Volumetric Strain ◽  
Apparent Volume ◽  
Differential Pressure ◽  
Simple System ◽  
Measuring System ◽  
Volume Changes ◽  
Ambient Temperatures ◽  
Triaxial Apparatus

A new simple system for accurately measuring overall total volume changes in unsaturated soil specimens with a triaxial apparatus is introduced in this paper. The basic principle of the measuring system is to record changes in the differential pressure due to changes in the water level inside an open-ended, bottle-shaped inner cell caused by volume change in the specimen and inside a reference tube using an accurate differential pressure transducer. Several important steps were taken to improve the accuracy and sensitivity of the measuring system. Detailed calibrations were carried out to account for apparent volume changes as a result of changes in cell pressure, fluctuation in the ambient temperatures, creep in the inner cell wall, and relative movement between the loading ram and the inner cell. The calibration results demonstrate that the measuring system is reasonably linear, reversible, and repeatable. The estimated accuracy of the measuring system is in the order of 32 mm3 (or 0.04% volumetric strain for a triaxial specimen 38 mm in diameter and 76 mm in height) once the system is properly calibrated.Key words: unsaturated soils, volume-change measurement, open-ended, bottle-shaped, inner cell, differential pressure, calibration.

Buccal Fat Pad Sculpting for Lower Facial Contouring With 3-Dimensional Volume Assessment

2020 ◽  
pp. 074880682098086
Author(s):  
Robert T. Cristel ◽  
Benjamin P. Caughlin
Keyword(s):  
Soft Tissue ◽  
Volume Change ◽  
3D Imaging ◽  
Fat Pad ◽  
Buccal Fat Pad ◽  
Volume Changes ◽  
Tissue Volume ◽  
Soft Tissue Volume ◽  
The Face ◽  
The Mean

Buccal fat pad sculpting and removal (BFPS) can create narrowing of the lower 1/3rd of the face by selective removal and reduction of soft tissue volume. Three-dimensional (3D) imaging allows for quantitative and objective assessment of volume changes over traditional 2-dimensional photographs that has not been previously studied in BFPS. A prospective study was designed in consecutive subjects undergoing BFPS from April 2018 through March 2020. Only those patients that underwent solely BFPS were included. VectraXT 3D imaging and software was used to compare preoperative and postoperative volume changes. Fifteen patients were enrolled in the study with 2 males and 13 females. The mean length of follow up was 7.7 months (range: 1-21 months). All patients were found to have volume reduction in the area evaluated. The mean volume reduction of the selected mid-lower face in the frontal view was 7.2 mL on the left side and 7.5 mL on the right side. There was no statistical difference between the volume change when the 2 sides were compared (P= 0.82). This study demonstrate the use of 3D photography to objectively and quantitatively assess volume change following BFPS and that the volume removed is significant enough to demonstrate favorable results using 3D imaging. Buccal fat pad sculpting is a safe and reliable option for creating a narrowed lower one-third of the face. This is accomplished by selective fat removal and cautery induced reduction of the lower one-third of the face soft tissue volume. VectraXT 3D imaging and analysis is a powerful tool to objectively and quantitatively assess volume changes in BFPS.

Pultruding of Metal Powder Filled Glass Fiber Reinforced Polymer Composites

2016 ◽  
Vol 674 ◽  
pp. 48-53 ◽  
Author(s):  
Henri Rummo ◽  
Renno Veinthal ◽  
Aare Aruniit
Keyword(s):  
Iron Powder ◽  
Metal Powder ◽  
Test Material ◽  
Metal Powders ◽  
Glass Fiber Reinforced ◽  
Fiber Reinforced Polymer Composites ◽  
Specific Material ◽  
Powder Content ◽  
Work Done ◽  
Application Specific

The present article focuses on manufacturing of metal powder filled pultrusion profiles for electro-technical applications. Herein a set of test material has been reviewed, which was prepared with the aim to present an optimized composite structure with high metal powder content for magnetic slot wedge production, outperforming the products currently available by alternative technology – compression moulding.This article gives a short overview of incorporating fine metal powders as fillers into pultrusion process (including the technical challenges) and the experimental work done in the project. The selection and analysis of components have been briefly discussed along with the results of material tests conducted on prepared composite samples. Mechanical, dielectric and magnetic properties of the samples were studied at different filler loadings and compared to the properties of iron powder filled compressed laminates.Several application specific material properties were determined, including flexural strength according to ISO 178, volume and surface resistivity similarly to IEC 93, and relative permeability using vibrating sample magnetometer (VSM). Scanning Electron Microscope (SEM) and various image processing software were used to analyse the composition and microstructure of the material samples. Material test results are presented at different iron powder loadings from 20 to 55 wt% and recommendations given for optimal materials selection.

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