Ideally, the spots should be round and distinct from each other Fig. Spots with long tails on a TLC plate can translate to wide bands and possibly to overlapping compounds on the actual column. If you have tried several solvent systems and cannot find one that gives perfectly round spots, don't worry. As long as the separation between the spots is good Fig. In situation 3 in Fig.
This is not recommended if the yield is important. You will sometimes find that two or more solvents systems give adequate separation of your compounds or you will see people run a column with a solvent system that gives adequate, but not the best separation on the TLC plate.
So what affected their decision? If two solvent systems give similarly good separation, the cheapest of the non-halogenated solvents should be used. Typically, this will result in a hexanes:ethyl acetate mixture. If you are unsure of the relative cost of a solvent, a good rule of thumb is to look at the size of the container.
Cheaper solvents are generally purchased in larger quantities than their more expensive counterparts. It is worth noting here that some cheap hexanes or petroleum ethers, especially those in plastic containers, often contain saturated hydrocarbons that are hard to remove and can make interpretation of NMR spectra difficult, especially in the 1—1.
In these cases, the solvent can be distilled prior to use time consuming , or you can use a better-grade solvent more expensive. The argument for choosing between two solvents with similar separation and different boiling points is simple: Always chose the lower boiling solvent. You will save yourself a lot of time and effort in the long run as higher-boiling solvents will take longer to evaporate and require heating or reduced pressure to remove when you try to recover your compound from solution.
Some would argue that this is the least important factor when setting up a column. Indeed, in theory it is possible to use a very thin column with a long length of silica or a thick column with shorter length of silica to equal effect Fig. Figure 5. Choice of column size is less important than the amount of silica used.
However, in practice, most people will choose a column size that allows them to fill column approximately one-third to a half full of silica — not including the solvent reservoir Fig. This, of course, depends on how much silica you will be using. How much silica you need is determined by how much of your sample you have to separate.
The ratio of silica to sample does not have to be exact, but should be in the right area to prevent waste of both time and resources. It is also advisable to measure the silica by weight rather than volume as the density of silica can vary depending on type. The other factor affecting the amount of silica required is how easy or difficult the separation is going to be.
This is determined by running TLC as part of the process of choosing a solvent see above. There is no thumb rule for minimum or maximum distances. It all depends on the layout of the building and how cleverly an engineer is able to design it to maximise its functionality. Dear sir I want make a 3 story building of sq.
So I want to know the column to column distance,size,tmt bar, concrete grade etc. This website is only for information purposes. You must employ a certified Civil engineer for any building works. It is unwise to be doing it yourself. Please advise. I wish it was as simple as that Prashant. There is a need for the surveying of the site prior to making calculations for foundations, columns and beams of the building.
There is not a set way of doing a column design. I would recommend that you get it designed by a certified Structural Engineer.
My structural engineer is just started his consultancy, I would like reconfirm the strengths. Please help me. Remember to use M20 grade concrete and FE steel. It will depend what is resting on it. How big a structure is it? How many columns and beams are there? Please, we want to start a single story with gallery church auditorium with a capacity of congregation.
Hi Daniel Where are you based? The column and beam design really depends on the floor plans and elevations. Let me know if you are interested in getting it professionally designed. Hi, we r constructing a school building, Need a advice for stage of 36ft by 22ft End to end column Pl let me know the size of bar..
Sir, i need to know what dimension of columns are used in a 15 to 20 storey building and also the span between the two columns. Larger structures are a lot more complicated. Newer construction techniques have really helped.
Mivan formwork technology is being used on a large scale for residential towers. Post-tensioning structures are preferred for commercial and office buildings. Really way above my skill level. It can be done by designing beams and slab for cantilever. But, cost will be more. Compared to frame support design. How much steel can be saved on moving to High strength steel bars i. How to calculate how many TMT bars are required and of what size?
Also how to know which concrete grade is required M30 or M40 etc? If we use Fe from Fe , how much percentage saving is there? I mean will there be the reduction in bar size or what? Properties of Fe and Fe below Your help is solicited. Generally, we preselect the grade of concrete and grade of steel to be used based on experience and need. These days, for regular buildings up to 5 floors height, we use M20 concrete and Fe Steel.
For smaller structures, the client may insist on Fe steel. But in my opinion, Fe is economical. I have not used Fe in my projects, but in my opinion, concrete has a larger effect on the load carrying capacity of a column than steel grade.
We calculate loads on each individual columns, then calculate the size and steel required. If you choose M20 concrete, and Fe steel, the load carrying capacity of that column would be kN.
If you choose M20 concrete, and Fe steel, the load carrying capacity would be kN. If you choose M15 concrete, and Fe steel, the load carrying capacity would be kN. If you choose M25 concrete, and Fe steel, the load carrying capacity would be kN. If you choose M25 concrete and Fe steel, the load carrying capacity would be kN. In the end, a qualified structural designer would be able to give you a good, economical structural design.
It is always better to consult a professional for such purposes. Hi Benzu jk, my house under construction G floor is already completed. I would suggest you approach a local structural designer. Column and beam will have 12 mm TMT bars and m20 grade.
Total weight of First floor roof and beams is Kn. So please tell me is it a good structure or need improvement. The best option would be to consult a structural designer. I have a technical question, I recently bought a land and started construction in rainy season. It is a very large structure. I request you to get detailed drawings from a qualified structural designer. You will get foundation designs, plinth beam designs, column designs, slab designs, staircase design.
Please consult a qualified designer instead of risking it on your own. My constructor proposing 10 columns. Can you give your suggestion. There are also two columns at center line of 50ft side. Total 16 nos. Require drawing if possible. In this we calculate kg. But after tendering party give design at time of ground beam. And total steel used by us iskg. I gave him in return to pay extra for steel. There is a dispute matter but I want to know I calculate steel is right.
So I request to you to give me advise the detail of slab, column, footing, beam, plinth and its steel members. I would suggest you use software like Staad pro or ETabs for analysis.
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Well, I think the same thing about columning.
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