Studies of Relaxation of Metallic Glasses by Dilatometry and Density Measurements

1983 ◽  
Vol 28 ◽  
Author(s):  
R.W. Cahn ◽  
N.A. Pratten ◽  
M.G. Scott ◽  
H.R. Sinning ◽  
L. Leonardsson
Keyword(s):  
Intermediate Stage ◽  
Glass Ribbon ◽  
Length Change ◽  
Experimental Conditions ◽  
Density Measurements ◽  
Density Reduction ◽  
Before And After ◽  
Recovery Annealing ◽  
Length Changes ◽  
Glass Rods

ABSTRACTHigh-precision density measurements on coldrolled Pd77.5Cu6Si16.5 glass rods before and after relaxation anneals showed that 30 – 40% rolling leads to a density reduction of ∼0.14%, recoverable on subsequent annealing below Tg. This change is about half of the density increase attainable by recovery-annealing the as-quenched glass.Density changes in Fe40Ni40B20 glass ribbon, resulting from recovery-annealing, were studied indirectly by measuring isothermal length changes through dilatometry of foil sandwiches. The experimental conditions for reliable isothermal dilatometry, using a commercial instrument, are outlined. It was found that the kinetics of length change in the longitudinal and transverse directions were quite different, being faster in the former. Prolonged recovery-annealing prior to dilatometry removed this difference. The intermediate stage of each isotherm followed loqt kinetics.Experiments were performed with Fe40Ni40B20, Ni64Zr36 and Cu66Ti34 to search for a reversible component of length change during cyclic isothermal holds at two temperatures. Such a component probably exists but is extremely small, less than 1% of the limiting irreversible length change.The implications of the various findings are discussed in the light of recent literature.

Relationship between diaphragm length and abdominal dimensions

1986 ◽  
Vol 61 (5) ◽  
pp. 1815-1820 ◽  
Author(s):  
M. Decramer ◽  
J. T. Xi ◽  
M. B. Reid ◽  
S. Kelly ◽  
P. T. Macklem ◽  
...  
Keyword(s):  
Length Change ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Quiet Breathing ◽  
Cross Sectional ◽  
Respiratory Inductive Plethysmography ◽  
Before And After ◽  
Length Changes ◽  
Crural Diaphragm ◽  
The Relationship

We examined the relationship between changes in abdominal cross-sectional area, measured by respiratory inductive plethysmography, and changes in length in the costal and crural parts of the diaphragm, measured by sonomicrometry, in nine supine, anesthetized dogs. During passive inflation, both parts of the diaphragm shortened and abdominal cross-sectional area increased. During passive deflation, both parts of the diaphragm lengthened and abdominal cross-sectional area decreased. We subsequently used the relationship between costal and crural diaphragmatic length, respectively, and abdominal cross-sectional area during passive inflation-deflation to predict the length changes in the costal and crural diaphragm during quiet breathing before and after bilateral phrenicotomy. In the intact animal the inspiratory shortening in the crural diaphragm was almost invariably greater than predicted from the relationship during passive inflation. During inspiration after phrenicotomy the crural diaphragm invariably lengthened, whereas the costal diaphragm often shortened. In general there was a good correlation between the measured and predicted length change for the crural diaphragm (r = 0.72 before and 0.79 after phrenicotomy) and a poor one for the costal diaphragm (r = 0.05 before and 0.19 after phrenicotomy).

scholarly journals Adsorption Studies on Magnetic Nanoparticles Functionalized with Silver to Remove Nitrates from Waters

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1757
Author(s):  
Yesica Vicente-Martínez ◽  
Manuel Caravaca ◽  
Antonio Soto-Meca ◽  
Miguel Ángel Martín-Pereira ◽  
María del Carmen García-Onsurbe
Keyword(s):  
Magnetic Nanoparticles ◽  
Nitrate Content ◽  
Adsorption Efficiency ◽  
Experimental Conditions ◽  
Dependent Behavior ◽  
Before And After ◽  
Naoh Solution ◽  
High Concentrations ◽  
Interference Studies

This paper presents a novel procedure for the treatment of contaminated water with high concentrations of nitrates, which are considered as one of the main causes of the eutrophication phenomena. For this purpose, magnetic nanoparticles functionalized with silver (Fe3O4@AgNPs) were synthesized and used as an adsorbent of nitrates. Experimental conditions, including the pH, adsorbent and adsorbate dose, temperature and contact time, were analyzed to obtain the highest adsorption efficiency for different concentration of nitrates in water. A maximum removal efficiency of 100% was reached for 2, 5, 10 and 50 mg/L of nitrate at pH = 5, room temperature, and 50, 100, 250 and 500 µL of Fe3O4@AgNPs, respectively. The characterization of the adsorbent, before and after adsorption, was performed by energy dispersive X-ray spectroscopy, scanning electron microscopy, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. Nitrates can be desorbed, and the adsorbent can be reused using 500 µL of NaOH solution 0.01 M, remaining unchanged for the first three cycles, and exhibiting 90% adsorption efficiency after three regenerations. A deep study on equilibrium isotherms reveals a pH-dependent behavior, characterized by Langmuir and Freundlich models at pH = 5 and pH = 1, respectively. Thermodynamic studies were consistent with physicochemical adsorption for all experiments but showed a change from endothermic to exothermic behavior as the temperature increases. Interference studies of other ions commonly present in water were carried out, enabling this procedure as very selective for nitrate ions. In addition, the method was applied to real samples of seawater, showing its ability to eliminate the total nitrate content in eutrophized waters.

scholarly journals Experimental Study on the Water Selective Dense Membrane under an Absolute Pressure Difference with Simplified Test Method

2021 ◽  
Vol 11 (4) ◽  
pp. 1710
Author(s):  
Jinwook Lee ◽  
Hyo-Sun Kim ◽  
Donik Ku ◽  
Jihun Lim ◽  
Minkyu Jung ◽  
...  
Keyword(s):  
Measurement Methods ◽  
Test Method ◽  
Coefficient Of Performance ◽  
Absolute Pressure ◽  
Air Conditioner ◽  
Experimental Conditions ◽  
Simple Method ◽  
Performance Factors ◽  
Dense Membrane ◽  
Before And After

Membrane-based vacuum dehumidification technology is currently being actively studied. In most studies, the performance of the membrane-based systems is evaluated under the assumption that the membrane can achieve ideal separation, which results in ideal coefficient of performance (COP) values. However, the performance factors for membranes vary depending on the experimental conditions and measurement methods. Therefore, relevant values can only be calculated if the data are measured in an environment close to that of the application conditions. The cup measurement method is a simple method to measure the permeability, however, there are limitations regarding adding variables during the experiment. To overcome these limitations, a new experimental device was constructed that combines pressurized cell with the cup method. Using the device, the performance of polyethylene-amide-bonded dense membranes was evaluated under conditions where absolute pressure differentials occurred before and after the membrane, such as in air conditioner dehumidification systems.

scholarly journals Medial collateral ligament reconstruction graft isometry is effected by femoral position more than tibial position

2021 ◽  
Author(s):  
Christoph Kittl ◽  
James Robinson ◽  
Michael J. Raschke ◽  
Arne Olbrich ◽  
Andre Frank ◽  
...  
Keyword(s):  
Medial Collateral Ligament ◽  
Knee Flexion ◽  
Length Change ◽  
Collateral Ligament ◽  
Complex Behaviour ◽  
Femoral Attachment ◽  
Attachment Sites ◽  
Custom Made ◽  
Length Changes ◽  
Graft Length

Abstract Purpose The purpose of this study was to examine the length change patterns of the native medial structures of the knee and determine the effect on graft length change patterns for different tibial and femoral attachment points for previously described medial reconstructions. Methods Eight cadaveric knee specimens were prepared by removing the skin and subcutaneous fat. The sartorius fascia was divided to allow clear identification of the medial ligamentous structures. Knees were then mounted in a custom-made rig and the quadriceps muscle and the iliotibial tract were loaded, using cables and hanging weights. Threads were mounted between tibial and femoral pins positioned in the anterior, middle, and posterior parts of the attachment sites of the native superficial medial collateral ligament (sMCL) and posterior oblique ligament (POL). Pins were also placed at the attachment sites relating to two commonly used medial reconstructions (Bosworth/Lind and LaPrade). Length changes between the tibiofemoral pin combinations were measured using a rotary encoder as the knee was flexed through an arc of 0–120°. Results With knee flexion, the anterior fibres of the sMCL tightened (increased in length 7.4% ± 2.9%) whilst the posterior fibres slackened (decreased in length 8.3% ± 3.1%). All fibre regions of the POL displayed a uniform lengthening of approximately 25% between 0 and 120° knee flexion. The most isometric tibiofemoral combination was between pins placed representing the middle fibres of the sMCL (Length change = 5.4% ± 2.1% with knee flexion). The simulated sMCL reconstruction that produced the least length change was the Lind/Bosworth reconstruction with the tibial attachment at the insertion of the semitendinosus and the femoral attachment in the posterior part of the native sMCL attachment side (5.4 ± 2.2%). This appeared more isometric than using the attachment positions described for the LaPrade reconstruction (10.0 ± 4.8%). Conclusion The complex behaviour of the native MCL could not be imitated by a single point-to-point combination and surgeons should be aware that small changes in the femoral MCL graft attachment position will significantly effect graft length change patterns. Reconstructing the sMCL with a semitendinosus autograft, left attached distally to its tibial insertion, would appear to have a minimal effect on length change compared to detaching it and using the native tibial attachment site. A POL graft must always be tensioned near extension to avoid capturing the knee or graft failure.

Slip Casting Used as a Forming Technique for Hydroxyapatite Processing

2016 ◽  
Vol 720 ◽  
pp. 219-222 ◽  
Author(s):  
Rubens Lincoln Santana Blazutti Marçal ◽  
Daniel Navarro da Rocha ◽  
Marcelo Henrique Prado da Silva
Keyword(s):  
Slip Casting ◽  
Ceramic Materials ◽  
Processing Route ◽  
Ceramic Suspension ◽  
Polyethylene Glycol 400 ◽  
Density Measurements ◽  
Hydroxyapatite Powder ◽  
Heat Treated ◽  
Thermal Phase ◽  
Before And After

Ceramic materials have particular properties when compared to other classes of materials, exhibiting poor ductility as an example. Slip casting is a widely used ceramic forming technique, and already established in the literature and in the ceramic industry. This study aims to present slip casting as a processing route for producing hydroxyapatite (HA) struts, and show the thermal phase stability. The ceramic suspension was produced and stabilized with hydroxyapatite powder, deionized water and polyethylene glycol 400. The slip was poured into gypsum mold. The green bodies were heat treated at 900 and 1100°C. Hydroxyapatite was the only phase present in all samples, before and after heat treatments. Density measurements showed that the densification was higher for the ceramic bodies sintered at 1100°C, when compared to the ones calcined at 900°C.

The location and mechanism of electromotility in guinea pig outer hair cells

1993 ◽  
Vol 70 (2) ◽  
pp. 549-558 ◽  
Author(s):  
R. Hallworth ◽  
B. N. Evans ◽  
P. Dallos
Keyword(s):  
Guinea Pig ◽  
Hair Cells ◽  
Outer Hair Cell ◽  
Length Change ◽  
Opposite Polarity ◽  
Outer Hair Cells ◽  
Response Amplitude ◽  
Change Function ◽  
Length Changes ◽  
Diameter Change

1. The microchamber method was used to examine the motile responses of isolated guinea pig outer hair cells to electrical stimulation. In the microchamber method, an isolated cell is drawn partway into a suction pipette and stimulated transcellularly. The relative position of the cell in the microchamber is referred to as the exclusion fraction. 2. The length changes of the included and excluded segments were compared for constant sinusoidal stimulus amplitude as functions of the exclusion fraction. Both included and excluded segments showed maximal responses when the cell was excluded approximately halfway. Both segments showed smaller or absent responses when the cell was almost fully excluded or almost fully included. 3. When the cell was near to, but not at, the maximum exclusion, the included segment response amplitude was zero, whereas the excluded segment response amplitude was nonzero. In contrast, when the cell was nearly fully included, the excluded segment response amplitude was zero, but the included segment response amplitude was still detectable. A simple model of outer hair cell motility based on these results suggests that the cell has finite-resistance terminations and that the motors are restricted to a region above the nucleus and below its ciliated apex (cuticular plate). 4. The function describing length change as a function of command voltage was measured for each segment as the exclusion fraction was varied. The functions were similar at midrange exclusions (i.e., when the segments were about equal length), showing nonlinearity and saturability. The functions were strikingly different when the segment lengths were different. The effects of exclusion on the voltage to length-change functions suggested that the nonlinearity and saturability are local properties of the motility mechanism. 5. The diameter changes of both segments were examined. The segment diameter changes were always antiphasic to the length changes. This finding implies that the motility mechanism has an active antiphasic diameter component. The diameter change amplitude was a monotonically increasing function of exclusion for the included segment, and a decreasing function for the excluded segment. 6. The voltage to length-change and voltage to diameter-change functions were measured for the same cell and exclusion fraction. The voltage to diameter-change function was smaller in amplitude than the voltage to length-change function. The functions were of opposite polarity to each other, but were otherwise similar in character. Thus it is likely that the same motor mechanism is responsible for both axial and diameter deformations.

Caffeine counteracts the ergogenic action of muscle creatine loading

1996 ◽  
Vol 80 (2) ◽  
pp. 452-457 ◽  
Author(s):  
K. Vandenberghe ◽  
N. Gillis ◽  
M. Van Leemputte ◽  
P. Van Hecke ◽  
F. Vanstapel ◽  
...  
Keyword(s):  
Intermittent Exercise ◽  
Creatine Supplementation ◽  
Knee Extensors ◽  
Caffeine Intake ◽  
Resonance Spectroscopy ◽  
Experimental Conditions ◽  
Before And After ◽  
And Performance ◽  
Exercise Fatigue ◽  
Voluntary Contractions

This study aimed to compare the effects of oral creatine (Cr) supplementation with creatine supplementation in combination with caffeine (Cr+C) on muscle phosphocreatine (PCr) level and performance in healthy male volunteers (n = 9). Before and after 6 days of placebo, Cr (0.5 g x kg-1 x day-1), or Cr (0.5 g x kg-1 x day-1) + C (5 mg x kg-1 x day-1) supplementation, 31P-nuclear magnetic resonance spectroscopy of the gastrocnemius muscle and a maximal intermittent exercise fatigue test of the knee extensors on an isokinetic dynamometer were performed. The exercise consisted of three consecutive maximal isometric contractions and three interval series of 90, 80, and 50 maximal voluntary contractions performed with a rest interval of 2 min between the series. Muscle ATP concentration remained constant over the three experimental conditions. Cr and Cr+C increased (P < 0.05) muscle PCr concentration by 4-6%. Dynamic torque production, however, was increased by 10-23% (P < 0.05) by Cr but was not changed by Cr+C. Torque improvement during Cr was most prominent immediately after the 2-min rest between the exercise bouts. The data show that Cr supplementation elevates muscle PCr concentration and markedly improves performance during intense intermittent exercise. This ergogenic effect, however, is completely eliminated by caffeine intake.

scholarly journals Running velocity at the ventilatory threshold and at VO2max, before and after the eight-week cardiovascular endurance training

2005 ◽  
Vol 58 (1-2) ◽  
pp. 27-31
Author(s):  
Stanimir Stojiljkovic ◽  
Sanja Mazic ◽  
Dejan Nesic ◽  
Sasko Velkovski ◽  
Dusan Mitrovic
Keyword(s):  
Endurance Training ◽  
Ventilatory Threshold ◽  
Exercise Program ◽  
Test Results ◽  
Final Test ◽  
Experimental Conditions ◽  
Cardiovascular Endurance ◽  
Before And After ◽  
Test Velocity ◽  
Male Subjects

Introduction The purpose of this research was to compare changes in running velocity at ventilatory threshold with the veliocity at VO2max, before and after the eight-week exercise program. Material and methods 32 male subjects (age: 22.3? 2.5 years, height: 179.8? 7.6 cm, body mass: 76.8? 9.0 kg) performed a progressive test for ventilatory threshold (VT) measurement and VO2max on treadmill. After 8 weeks of endurance training (3 times per week, 30 to 70 min, in different zones in respect to the ventilatory threshold) the performed the same test. Results Running velocity at ventilatory threshold increased significantly (p=0.000I), between initial and final measurements (10.88?2.09, 12.94? 1.90 km/h, respectively): as well as at VO2max H4.63?1.86, 16.44?1.59 km/h, respectively). At the initial test, velocity at ventilatory threshold was 74.11% of VO2max. At the final test, velocity at ventilatory threshold was 78.43% of VO2max. Running velocity at ventilatory threshold has significantly increased at final test (p=0.001). Discussion Running velocity at ventilatory threshold has significantly increased after eight weeks of endurance training (p -0.001), when expressed in absolute values and percentage of velocity at vo2max. Conclusion Comparison between the initial and final test demonstrated a significant increase of observed variables, under experimental conditions: at final test running velocity has increased at ventilatory threshold, in respect to absolute values and expressed as percentage at VO2max. .

scholarly journals Comparison of Nifedipine and Isoxsuprine to Cervical Length in Threatened Preterm Labor

2021 ◽  
Vol 4 (1) ◽  
pp. 56-63
Author(s):  
Triyoga Pramadana ◽  
◽  
Anita Rachmawati ◽  
Dini Pusianawati
Keyword(s):  
Pregnant Women ◽  
General Hospital ◽  
Preterm Labor ◽  
Cervical Length ◽  
P Value ◽  
Inclusion Criteria ◽  
Key Word ◽  
Before And After ◽  
Threatened Preterm Labor ◽  
Length Changes

Objective: This study aimed to determine differences in cervical length changes between administration of nifedipine and isoxsuprine. Method: Subjects of the study were pregnant women who meet the inclusion criteria (n=16). Treatments were given for 48 hours. Parameters measured was the cervical length before and after the administration of nifedipine and isoxsuprine. This study was conducted in Dr. Hasan Sadikin General Hospital from January until April 2020. Result: Less shortening of the cervical length after administration of tocolytic isoxsuprin for 48 hours compared with tocolytic nifedipine and statistically significant with p value of 0.0001 (p<0.05) using Paired T tests. Conclusion: Isoxsuprin is more effective to prevent shortening of the cervical length compared to nifedipine in cases of threatened preterm labor. Key word: Nifedipine, Isoxsuprine, cervical length, threatened preterm labor

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