what are the durability factors in cavity wall construction? brick block formation
132284
When you fill the cavity with rubble it defuses the battering ram strike over a greater area.
120145
There is likley not to be a definitive answer to this question. \n\nAncient walled towns / fortresses (eg, Jericho, Troy, assorted Mesopotamian cities / strongholds, ...) very often were built with narrow, often low, passages through the walls. At least one ancient gate through the Jerusalem wall  was built just so. Walls being quite thick (multiple yards in some cases), tall (the "towering walls of Illium"), and often non-flammable (clay, rock, brick, ...), the only practicable way for a beseiging army to get in was through the doors (stout, and most likely wooden if perhaps with metal cladding at times). The battering ram was a natural resort. They were used (in variants) at sea (triremes were primarily used as battering rams when in a direct attack as at Salamis and other battles) and though actuall battering rams have not survived from ancient times (too useful as splintered firewood, one presumes), they are likely to be quite ancient. Being simple, and more or less easily improvised from a locally available tree trunk and so easily replaced at need, they are very likley to have been used before we have historical records of any kind. \n\nCatapults are also ancient. They were certainly known in late Greek times (as at the seige of Syracuse most remembered for the murder of Archimedes at its end), and portably, later in Roman times as at the seige of Masada in Palestine. Seige warfare in the Eastern Mediteranean or in Mesopotamia likely used them even earlier. However, because catapults require high level cordage technology (bad rope = nothing gets heaved), and relatively high precision wood joinery skills, it is clear that the very first attacks on fortified structures / camps would not have been by catapult since the requiste prior technologies must have been both developed to a high degree, and available simultaneously, before research and development could pay off in a working catapult of any sort. \n\nSuch a keep, if having a relatively weak door or gate, could be attacked with an easily 'built' battering ram, absent a catapult. The problem for such an attack is protecting those lugging the battering ram from missles from the walls. Personal shields, common from very early times and attested by carvings and images from nearly everywhere, have an obvious application.\n\nOn the whole then, I would suggest, in the absence of good    archeological sample evidence, that battering rams, being simpler, predate catapults of any kind in seige warfare. \n\nBut time (based on water supply or food supply or disease) was probably an earlier seige weapon than either, and continued to be so even after the development of organized structures wihin which to lug a battering ram or of very sophisticated catapult variants. Consder the seige in the Crimea at which it is said the first known European cases bubonic plague occurred. A body of a soldier who died of plague is supposed to have been catapulted over the walls to speed up the diesase weapon.
516514
weathering of rocks due to wind,flowing water
520563
The Brick wall ? don't worry you'll get over it
56575
I am having a hard time picturing the gaps you are trying to fill, so I'm not sure if my ideas will be helpful.  Perhaps you could try ceramic as an insulator.  It also depends on how long the surface will be exposed to the high temperatures.  If its not too long, perhaps you could use wood that has been soaked overnight in water.\nThe aluminum isn't a bad idea, but perhaps you need thicker aluminum.  Like maybe cut open a few soda cans and flaten the result into a crude sheet of aluminum.  Maybe two or three layers worth would do the trick.\nMaybe some gravel or stones?\nWell, those are just some ideas.  Not sure if any of them will work, but maybe that gives you some things to explore.
573925
See the ref. cited below. There are several resonant frequencies. Some are due to vibration of the box panels, and there is not enough information in your question to determine that. For application as a speaker box, you want to avoid those resonances anyway, which means using wood thicker than 1 cm (2 cm or more would be preferable) and/or adding damping material. The other resonances are due to the vibration of the air in the box. If the box is vented or ported, the dominant vibration mode is a cavity resonance which you can calculate from the "cavity resonant frequency" link in the ref. Other resonances are similar to room resonance, the natural frequency of wall to opposite wall bounce. This frequency is equal to twice the distance between walls divided by the speed of sound. However, wall bounce is undesirable as it produces a single strong peak response at resonance, whereas a ported box or "bass reflex" setup will reduce and spread out the speaker's resonant frequency, providing a smoother and deeper bass response.\nEDIT (responding to your followup questions):\nIf I interpret you correctly, you are talking about nothing but a box, no port, no speaker. In that case you don't have the strong resonance of a ported cavity but just the weaker resonances of material plate stiffness/mass/damping and the closed-cavity (wall bounce) modes. I expect if you hit the box you are exciting the plate modes most strongly. ln other words you have sort of a percussion instrument, but with a lot of damping and without a membrane which would give it a more definite pitch as in a drum. On the other hand if you put inside the box a mike and a source of bounce mode excitation like a speaker, the mike would probably pick up the bounce modes when you tuned the speaker to drive them. Both the speaker and the mike would have to be suitably located (away from the null points of the modes) for maximum response. The second reference below discusses closed-cavity ("room") resonance in detail.
19985
Here is a try section the area off with wood trenches covered with plastic  so the excess water goes into the trench waterhose that section down. It should freeze over in the right weather. (Make sure the plastic is tight so when laying it place the wood blocks on top of it.
442967
1. Water (surface run-off, streams, rivers, sea currents, etc), Wind and Gravity\n2. Seas, lakes, rivers, estuaries etc\n3. Compaction.\n4. Cementation.
551759
Reproduction detail\n1. use of finer sand, \n2. Hydrostatics of the molten metal \n3. same as in #2\n4.Hmmm?\n5.To avoid air voids :). \n6. Not enough water and the sand will crumble, too much water the medium will be too fluid or too much of steam will be produced during casting damaging the mold from inside out.
72195
I myself hate it when I have to answer like this.......that it depends on many factors...\n\nBut in this case it really does! You see, designing the features require complete knowledge of the area. You may then refer to any geotech engg book and will find some good answer. Even a Foundation of Geotech engg book will be enough
201605
Look it up.  I'm fairly sure that was the point of the question.\n\n*speech mode*\nWhen teachers give you assignments, they don't just want you to learn the facts, they also want you to learn how to GET the facts.  How Rome improved bricks may not seem like something you will need to know in the future, but the ability to find the answers to this sort of question will be invaluable to you in the future.\nLearn to use search engines, and your library.
341209
let the dimensions be x*y\nxy=14400\nx=14400/y\narea of the three brick walls/running foot=(2x+y)brick and y glass\ncost=2x+y+1.88y\n=2x+2.88y\nexpressing x in terms of y\ncost=2(14400/y)+2.88y\n=(28800/y)+2.88y\ndC/dy=-28800/y^2+2.88=0\n=2.88y^2=28800\ny^2=10000\ny=100\nx=144\nthe dimensions are\n144*100
50787
The transmission of the various modes of vibration of an earthquake to a building can depend on whether the building is constructed on solid rock or on sand or silt.  Sometimes the excavation for the building and refill can also alter the ground response.  Sand and silt can actually amplify the effects on a building and earthquakes can actually liquify soft ground under certain cirstances especially when very moist.  You may not be able to build a buffer into the ground to protect the building.  Instead it may be necessary to obtain seismologist's estimates of the worst expected earthquake g-loads for the area and a geologist's estimates on how the selected site will react.  With that information a building can be designed to withstand the site response to an earthquake with room to spare (factor of safety).  Good luck.
72268
the needed papers/license to build something like that.\n\nThe construction should be checked also before building (strong enough etc)
137715
Found a good diagram here\nhttp://www.laynetworks.com/Block%20diagram%20of%20the%20Pentium.htm
390085
There are no set values for either the ingredients or the percentages of composition for water based wall putties.\n\nWhite cement, gray cement, polymers and plastic resins, various chemicals and mineral fillers (including plaster of Paris and gypsum) have all been used.  Sometimes pigments are added.\n\nSome of these putties are designed to stop water seepage and others are not.
571438
I think brick is so beautiful, is eclectic feeling, and has character and history. vinyl and stucco are so unoriginal. of course, brick is more expensive, but it is durable and you  wont have any problems with it so it would be well worth the money in my opinion.