- You Zhiren added an answer:5What are the best methods of preparation of C12A7-base glasses?At higher temperatures the melt is clear (transparent) but at lower than 700C is the dark-green. Is super quenching the solution?
C12A7 was hard to prepare by conventional container method. I suppose one containerless method named aerodynamic levitation method that could cool down the C12A7 melt without contact with the crucible . In fact, we have made such C12A7 glasses in our lab. If you are still interested, contact me.Following
- Linda Nait-Ali added an answer:3Which type of fiber (polyester or polypropylene ) is best for Reinforcing soil pondash mixes and why ?
From a literature review I understand that the PES has higher creep resistance (retention of tensile properties over long duration of time) than PP
I am a little confused regarding adhesion.
As far as I know, polyester is the only type of fiber used for this application because of its mechanical stability over time (creep). Then, there is the question of durability. This can be calculated according to litterature, the type of fiber, service duration, temperature, pH. Hydrolysis is a process that depends on temperature.Following
- Nikhila Balasubramanya added an answer:8How do I take my single crystal out of the ampoule/quartz glass on which it is stuck? Is there any special technique for Bi2Te3?
I know I have to break the quartz glass, I am only worried if it induces stresses in the crystal. If there are chemicals to dissolve the ampoule, pls suggest. Also, If there is any special technique to cleave layers out of the layered crystal of Bi2Te3, please suggest.
Thank you Yu. M. Ivanov.
- Erenilton Pereira da silva added an answer:7How can I calibrate an AFM to Kelvin Problem experiment?
I am facing some problems with Kelvin Problem experiment. I am conducting tests on ZK40 and ZK60 alloys with rare earth (RE) addition and I would like to have the potential map for a selected area in order to evaluate the potential of the intermetallic compounds on the comparison with the Mg matrix. I am using a Nanovea Flex AFM and we are setting up the experiments using the one tapping pass, i.e. not the two pass technique, where the height data is recorded in tapping mode during the first pass and the tip lifts above the surface to an adjustable lift height and scans the same line.
The samples were prepared up to 0,25 µm diamond solution and a 100 µm x 100 µm area is been recorded. We are keeping the set point in 50%, the P-gain in 1000, the I-gain in 100 and the D-gain zero. The tip voltage is 0V and the free vibration amplitude was kept 500 mV. However, I am not fully convinced these are the better parameters.
The values that I got are about 800 mV which is much higher than the obtained by other researches for this type of alloy. Basically they have found two main phases: a lamellar one, and some particles that are rich in rare earth elements. The first one has a voltage less than 50 mV and the second one about 200 mV.
I may think that our main problem is that the tip has been not calibrated. In the literature, it is suggested that we should calibrated it using a sample of aluminun with a gold layer coating. Does anyboday know how to perform this calibration?
In this way, something seems to be wrong for the setup we are using.
Does anybody know what are the mistakes the I am doing or how to setup the experiment properly?
Thanks in advance!
thanks for attention,
We did some experiments recently, using a equipment with some improvement. The partial result was great.
I believe the main cause of errors in the initial tests, it was the humidity control, we were working with 55% as literature and recently with 5% indicated by an expert in AFM.Following
- Karthik S Bhat added an answer:2I encounter a problem while coating calcium phosphate over polyamide substrate using PLD can any one suggest me the reason?
I am trying to coat Calcium phosphate over polyamide substrate using PLD but I can't get a uniform layer and to find the coating thickness in cross section is also difficult. The Substrate roughness is 4-8 um
You have mentioned that you are coating the preferred material on a polyamide substrate. So May I know the film deposition temperature ? I guess if you are using high temperature (above Tg), the polyamide may become visco-elastic in nature and hence the deposition may not be uniform in nature.
I am not sure about it.Following
- Miguel Baltazar Zamora added an answer:8Partial replacement of cement and sand with glass powder in concrete mix: Does the strength of concrete increase or decrease?
Does the strength increase or decrease? If it varies, to what extent does the replacement strength vary?
According to the water/cement ratio, if you substitute glass for cement the compressive strength decrease, if the glass is replaced by sand most likely will also decrease, glass in concrete is for architectural use.Following
- Enrique Maya added an answer:3What is the setup for a 3 electrode EIS using a Solartron 1260 in conjunction with a 1287? And how can this setup be verified with ZPlot?
I have been setting up an EIS system using a Solartron 1260 in conjunction with the 1287 model and a Princeton Research Flat 3 electrode cell. From my understanding, the 1287 is hooked up to the 1260 via ports in the back of the console (Pol in, V out, and I out from the 1287 to Gen input, V1HI and V2HI on the 1260 resepctively). Both of these are attached to a PC using the GPIB interface and are run with ZPlot/ZView.
I am fairly certain that the 1260 is in working condition (after comparing it with a similar HP model) but am not sure about the 1287. I was wondering if there was any alternate configurations for the potentiostat?
This setup has yeilded no useful data, but is what other researchers have done in the past (including the Technote 31 from Solartron).
Hope this information works. I found it on the Zplot software help.Following
- Sallal Abid added an answer:2How can I simulate Phase change materials in 2D model or 3D in comsol multi-Physics?
I have simulated 1 D model of different phase change materials. But as we know that if phase change materials heated and become in liquid then it start flowing from higher density region to lower density region. But in 1 D model the flow of melted Phase change materials can not take place. Please suggest
If there is a built in model in COMSOL ...then it is great and you can directly use it....otherwise ..it may works if you define functions for the variable material properties in the Global definitions and then re-define it (with units) in the COMSOL physic that you are usingFollowing
- Rudolf Gradinger added an answer:9Is it possible to join carbon and metal parts in a cost-effective way?
I am exploring the viability of a new product where carbon fiber and metal parts should be joined.
Being said that carbon is considered a non machinable material, how would it possible to assemble a part like this in a cost-effective way?
Dear Anna, we follow some technologies in which we use "Pins" bridging metal layers with FRP layers. The abstract to a recent paper reads as follows:
COMPOSITE TO COMPOSITE JOINT WITH LIGHTWEIGHT METAL REINFORCEMENT FOR ENHANCED DAMAGE TOLERANCE, S. Ucsnik et al ..., The increasing maturity of fibre reinforced plastics (FRPs) has led to the need for appropriate joining technologies for enhanced lightweight structures. This research work presents the FRP joining and reinforcement concepts "CMT pin" and "Sheet pin". Tensile tests of "CMT pin" and "Sheet pin" reinforced joint specimens are presented. Results are compared to titanium z-pin or unreinforced references. The 3D-shaped reinforcement elements do build up a beneficial form-fit with the CFRP components. This leads to distinct increase of mechanical joint properties. This research work proves a beneficial support and enhancement of "CMT pin" and "Sheet pin" reinforced / joint CFRP components. ..... see attachment.
- Xu Jianfeng added an answer:11What are some recipes for RIE of Titanium using gases SF6, O2, Ar, and/or Freon?I need to etch 400nm of Ti masked by positive photoresist (Shipley 1813) without touching the resist.
Hi, did you find some appropriate method to obtain RIE of titanium? I have no experience on dry etching.Following
- Mohammad Ali Ansari added an answer:6How can I determine the Oxygen content of pure Mg machining chips?
I am trying to evaluate the effect of Oxygen content on mechanical properties of solid-state chips recycling.
Oxide precipitation was primarily introduced from the machined chip surface.The relationship between the accumulated oxides and the total surface area of the machined chips in the recycled specimen can be estimated by Formula. Please see:
- Himansu Shekhar Mahapatra added an answer:6How could I mix polylactic acid with calcium carbonate with ease?
The issue I'm facing is pertinent to a PLA/CaCO3 hybrid. I'm required to find an efficient pre-mixing method whereby the polymer and ceramic could mix uniformly.
Please guide me if possible.
Javad Ghorban Daei
Can u use burnt/ calcined calcium carbonate?Following
- Alexander Kolpakov added an answer:15Do residual stresses in composite materials have a positive or negative influence on their use?Manufacture of composite materials induces stresses locked in them. Is it desired or not?
It depend on you.
Prestresed concrete is a technology.Following
- Serena Danti added an answer:3Are you familiar with a freeze thaw method to make hydrogels?
I am currently employing the freeze thaw method to synthesize 10% w/v polvinyl alcohol. However, I cannot get the solution to gel. It becomes a sticky paste instead. I am only using a refrigerator freezer. Is this enough? I am freezing it for 12 hours and thaw it at 12 h as well. Thank you.
Hi, I can provide you our method. Hydrolisis degree, Mw and freeze-thaw times are very important. A -20°C freezer is fine. Good luck!
- 10% (w/v) solution of PVA (99% hydrolyzed, Aldrich, Milan, Italy) in distilled water was prepared using autooclaving (at 120 °C for 20 min).
- The PVA solution was cooled down to 60 °C under magnetic stirring (keep it heated to handle a solution with reduced viscosity, otherwise you will need a special pipetter for viscosus liquids), and complemented with distilled water to reach a final PVA concentration of 2.5% (w/v). The solution was poured in multiwell plates.
- We use 8 freeze-thawing cycles. The first cycle consisted of overnight freezing at −20 °C, followed by 30 min defrosting at room temperature (RT). The first cycle enables the crystalite structures, so it is very important. The subsequent 7 cycles consisted of −20 °C freezing for 1 h, followed by 30 min deforsting at RT.Following
- R. D. Adams added an answer:7What is the reason for getting storage modulus of single cantilever mode is very high compare to the storage modulus of dual cantilever mode?
I did both single cantilever mode and dual cantilever mode of DMA test. I got the storage modulus of Single cantilever mode is very very high (120 GPA) compare to dual cantilever mode (10 GPA). What is the reason behind this?
Repeat the cantilever tests with similar specimens of steel or aluminium which have known moduli. With your own specimens, use the free-free bending of a uniform beam in vibration. Support at the nodes which are at the 1/4 points [roughly] on light cotton threads. Excite with a non-contacting method such as acoustically via a vibrator and a small plate. Record the acoustic signal given off with a microphone. Resonance is indicated when you get a sudden shift in phase between the exciter signal and the microphone. Check the nodes and mode of vibration by using powder [light sand] sprinkled on the vibrating beam.Following
- Young-woo Lee added an answer:4How to remove oxide film on the surface of intermetallic compounds?
I want to know how to remove oxide film.
To measure Fe and Al valence electron orbit, I tried to use UPS.
But I need to remove oxide film on the samples(Fe-Al compounds) FIRST.
So I'm going to do Ar sputtering.
However, there is no detailed procedure such as voltage, vacuum, DC or AC..
Can anyone explain detailed procedure of sputtering for removing oxide file?
or Is there another method to remove that?
Dear Dr. Sornadurai
Thanks for your opinions. I want to ask something;
Should I rinse the sample with DI water for using UPS after etching?
And how to know etching time?
Please check my questions.
- Zaid Alsmadi added an answer:7Is there a database available for mean-free-path (m.f.p) of particles in a vacuum?
Could any researchers provide links to a database of m.f.p of particles under vacuum conditions?
I am trying to compare the m.f.p of Ni, Al and several other metals under vacuum in order to understand the relationship between thin film formation and the particle's m.f.p.
Higher m.f.p means the particle takes a long time to reach the substrate. Thin film has low thickness, plus the possibility of back scatter.
the mean free path in vacuum is infinity ... since a "closed" geometry is required to define the path.
I believe you want to know the mean free at low pressure limit !
at low pressure the free path calculation is simple ... it follow the laws of kinetic theory of gases.
please see this article for more details
- Burhan Ullah added an answer:3How can I control the formation of major second phase CeO2 in the Cerium Doped SrTiO3 system?
I am working on cerium doped SrTiO3 system. But the problem which I facing is the formation of major second phase CeO2. How can I control this problem? Although I calcined and sinter the system in the reduce air furnace in the temperature range from 1150C to 1350C.
Respected Marcella Bini,
The ionic radii of Sr2+ is (1.44A or 0.144nm) while that of cerium Ce 3+(III) (1.34 A˚, 0.134nm) Ce4+ (0.087nm ) and Ti+4 (0.0605nm).
For x=.1, .2 and .3, its give the formation of solid solution, which conform that their ionic radii are comparable. But for doping above 0.3 there is major CeO2 Second phase which may due to the formation of grain boundaries. Dopant Ce ions with a small radius may form the core-shell-structured fine grains and thus the secondary phase CeO2 appears because of the segregation of small ions in the grain boundary regions, which decreased the solubility of Ce ions in Sr TiO3.
My question is that how we can control the formation of Ceo2 phase, although I sinter my sample in reducing air furnace, oxygen and nitrogen atmosphere furnace.Following
- Sabyasachi Roy added an answer:5Has anyone ever had the experience of having bumpy surface after making a zirconia /Alumina sample by SPS followed by thermal etch?
After making composite out of zirconia and alumina by SPS followed by grinding, polishing and thermal etch, my samples get bumps over surface. I'm not sure about the possible reasons. Please see attached example.
In production unit, we do get this type of bump by conventional sintering process also. This is due to entrapped gas. After Cutting across the bump will clarify the same. It happens when gases can not escape during their binder burn out stage ( can be due to high heating rate, minimum dwell time, high density on top surface compared to bottom part, improper mixing or non uniform mixing of binder etc)Following
- Ajeet Babu Kumar Parasumanna added an answer:3Is anyone familiar with Carburizing nitrogen/methanol atmosphere system?
We are making the assembly of the process in the foundry laboratory of the University of Antioquia (Medellin - Colombia), in order to supplement the training of students in the study of heat treatment of materials.
I would like to consult on the most important aspects to keep in mind for execution and implementation of the system Nitrogen / methanol.
- Ahmed Shawky added an answer:15What will be the best solvent (other than acetone) to disperse CNT?
This is for better dispersion and avoiding the CNT agglomeration
My opinion is to disperse not dissolve, dissolving CNTs is quit impossible, please consider sodium dodecyl sulfate (SDS)Following
- Milad Salarvand added an answer:13Which process is the most reliable way for joining of Al to Alumina?
According to literature, active brazing and diffusion bonding are the most reliable methods for joining of metals to ceramics. but in the case of joining of Al to Alumina there are two problems:
- In active brazing method, the brazing temperature is usually higher than 700 degree Celcius. therefore this method is not applicable for Al.
- Sufficient information about diffusion bonding of Al to Alumina is not available.
Thank you very much for your suggestions.Following
- Junyoung Kwon added an answer:3How can I etch the natural iron oxide grown on steel wire?
I want to utilize a steel wire as a gate electrode of TFT. Then, I have to deposit the gate dielectic(Al2O3) on the wire by atomic layer deposition process. However, there is a iron oxide between the iron gate and the alumina which induces leakage current and lack of uniformity of surface.
So, I want to etch this oxide. What is the best etching technique for better uniformity of the ALD deposited alumina surface?
Thank you for your clear answers. Have a nice day.Following
- Chenghui Zeng added an answer:3What is the cause of pure water flux variation in UF or NF polyethersulfone membrane?
I have tried to fabricate NF membrane using PES and NMP. but, when I prepare a solution, for example (18 %wt), and cast it into several sheets, then test their water flux, I get quite different flux among these membranes and even within the same membrane ( differences are sometimes double, 3 folds and more)....many thanks.
Now I get the same problem. I used the same membrane and same pressure. but the flux varies significantly. I think the problem might be caused by the membrane structure, especially for charged membranes. According to what I know, there are many functional groups at the surface of the membrane. and they can influence the permeate flux. But I dont know the exact reasons. Hope this could be helpful to you. If you get any new information on this issue, please share it with me. Thank you in advance.Following
- Jaronie Mohd Jani added an answer:8Can someone suggest how to determine the shape recoverability percentage of shape memory alloy?Shape memory alloys
Please remind, that the strain also changes with number of cycles performed.Following
- Zol Bahri Razali added an answer:1How to get yield pressure sigma from a modified Heckel equation?A modified Heckel equation involves a term K1P/sigma. How can we get sigma at a particular pressure from this equation?Following
- Jim Boland added an answer:12Why are residual stresses anisotropic ?
I have done XRD test for a cylindrical component which is previously being turned in lathe machine. I got negative value of stress i.e.compressive residual stress in axial direction and positive value i.e. tensile stress in circumferential direction. Why nature of stress is changing with direction ?
It is essential to know the following;
(1) the material being machined and any prior treatment given to that material - annealed, normalised, case hardened, cold rolled, extruded, evidence of preferred orientation in the material
(2) the cutting/machining conditions such as speed, depth of cut, use of a cutting fluid
(3) What were the stress levels in the starting material itself prior to machining - stresses calculated from the x-ray data?
(4) What levels of stress - compressive and tensile - were calculated in the machined component based on the x-ray data?
(5) I presume the person means axial as in the direction parallel to the cylindrical sample itself.
(6) Anisotropy would be readily explained if the material had a preferred crystallographic orientation and an anisotropic grain structure.Following
- W. Porzio added an answer:29How accurate is the measurement of grain size using XRD?Additionally, I want to know the ways to improve the accuracy.
the main problem of crystallite size in materials resides in the range. From 3 to 70 nm the methods based on Hosemann or Warren-Averback approches are quite reliable for organics or inorganics respectively, provided that accurate measurements are performed. The problems arise when the upper limit is exceeded in this case are HRTEM, AFM/STM or SEM are clearly preferable.Following
- Peiliang Cong added an answer:2Which organization or group give the specifications for the calcined bauxite used in road construction? What is the requirement for it?
Why the chemical composition of calcined bauxite using road are limited. such as aluminum oxide, silica, ferric and titanium dioxide.
There are an frenquce measurement for calcined bauxite in road application is chemical component. such as Al2O3 is not less than 88%. i don't know why the chemical component is be required.Following
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