Is there any way to land a rover on the Moon without using any thrusters?

Question: Is there any way to land a rover on the moon without using any thruster, with the help of Thermocol, Cotton, Bubble wrap or any other packaging material, like we can receive from online shop?
Comment: In theory, sure. You just need a big enough crumple zone. But since weight is the limiting factor, I doubt that it would be feasible.
Comment: @Rajath Pai: You don't actually need to orbit the moon to "land" there.  For instance, the early US Ranger probes were launched on a direct course.  You just need to build a probe that can withstand abrupt deceleration from Lunar escape velocity :-)
Comment: It's called Lithobraking: https://en.wikipedia.org/wiki/Lithobraking
Comment: Would bubble wrap explode in a vacuum? Hmm.
Comment: NO thrusters for landing or deorbiting? You need to slow down from an orbital velocity to reduce altitude and land, so would you edit your question to make it more clear? If it can use deorbiting retrothrusters, but not to land it can follow some of the ways described here http://pages.citebite.com/s3e3l8g4j0poy
Comment: @Schwern If bubble wrap exploded in a vacuum with nobody around to hear it, would it still make a noise?
Comment: @Polygnome Is that a very inefficient thruster?
Comment: Interesting , good to know @jamesqf
Comment: Do you allow decoupling of a large mass? E.g. having a 100kg lander sitting on a 10 ton lead weight, and decoupling via a spring-loaded mechanism shortly before touchdown, then utilizing crumple zones?
Comment: @Schwern No combustion, so I'd say no. But that is why I asked OP for clarification.
Comment: related to https://space.stackexchange.com/questions/4843/is-lunar-lithobraking-1-survivable-and-2-cheaper-than-a-rocket-landing
Comment: Does riding a space elevator on a cable hanging from the moon towards earth count?
Answer: It is not practical to use this approach from orbital (1.6km/s) or escape velocity (2.4km/s), for two major reasons. The first is the acceleration reason.
The kinematic for bringing objects to a stop under constant acceleration is
$$d = \frac{v^2}{2a}$$
from which we can quickly solve for the acceleration to be
$$a = \frac{v^2}{2d}$$
Even with 10 meters of padding, as @zeta-band used, the acceleration would be $283000\frac{m}{s^2} = 29000g$, which is roughly the acceleration experienced by electronics in artillery shells. So in theory we could build the electronics to survive the impact.
However, this is where the second issue arises. Even if a crumple zone of arbitrary size were to be used, there would be mechanical and material issues associated with the speed of sound in the material. The problem, in a nutshell, is that in ultra-high velocity impacts, even strong materials like steel splash and crack rather than deform neatly. In order to be effective, a crumple zone must effectively reduce the speed of sound in the material, spreading the shock of impact. However the velocities involved are too high. Our crumple zone would not act like the crumple zone in a car. In fact, the pressure wave indicating the start of the impact with the ground may only reach the payload ~50% faster than the ground itself, and that is if we use a sturdy crumple zone out of a material like aluminum or steel (former better for weight).
Items like bubble wrap, cardboard, foam cushions, things that we consider soft and suitable for packing do not have a high speed of sound. They would not even transmit the ground impact force until the spacecraft itself hit the ground.
Finally, I want to debunk the idea that one could "land" (come in on a strong tangent, rather than straight down) on a long runway on the moon. In theory, this is possible. Using ultra-strong alloys, one could (barely) make wheels that could spin up to the required velocity of 2.4 km/s. However the gyroscopic issues will be severe, not to mention the wheel balancing (and what happens when a wheel breaks?). One could even go simple and just slide it out on the longest slip n' slide ever built on or off this world. But hypervelocity issues strike again. Any rubbing surface at these speeds won't just heat up, they will plasmify. Atoms in the materials will impact so hard they simply get dislodged off the material completely. Even diamonds will degrade. Its not that any of these methods are impossible in principle, they are just impractical and the engineering challenges to make them work are monumentous.
So the upshot is that there must be some form of propulsion to slow the spacecraft down to land on the moon.
Comment: @JamesJenkins I reference the speed of sound in the material.
Comment: Ah, I see it is not the speed of sound on the moon, it is the speed of sound in the material, which is not dependent on air (or water) pressure.
Comment: Magnetic levitation was used in the Red Moon novel. No clue if it's realistic, but I don't see any immediate reason it would be impossible
Comment: can't we do litho braking like we do aero braking, bouncing off the surface, scratching and loosing a bit of velocity at each turn?
Comment: @JollyJoker Better hope that your insurance is paid up for that maglev catcher, if there are no emergency thrusters  to correct or ditch a payload that's coming in just slightly out of tolerance.
Comment: @notovny That is why I dismissed it as a possibility. Accuracy needed was just impossible. But the reverse works just fine!
Comment: @KevinFONTAINE - perhaps call it 'litho breaking' ?
Comment: What is the speed of sound on the moon?  It is a variable value on Earth not a static one.
Comment: I love the idea of lithobraking. Sound like a good alternative to Rapid Unplanned Disassembly.
Comment: unless you have a perfect surface, horizontal lithobraking will result in the spacecraft hitting a rock and bouncing off at a much larger angle than it came in with. So you get one lithobraking pass which converts your trajectory to a parabola, and you're back to a vertical/high-angle landing that has to dissipate all the energy at once.
Answer: Well, lunar escape velocity is 2.38 km/s. So this is about the speed that a rover dropped in from orbit (with no sideways velocity) will hit at. So let's take a guess at how many g's deceleration will be. Assume it has 10 meters of crumple to stop in. It will take it about 10/2380 seconds to stop. Which is .0042 seconds. Deceleration will be 2380 / .00042 = 566,666 m/s squared. Which is about 57,823 g's.
That's pretty tough to survive and still function.
Comment: This is a good estimate for the order of magnitude of the acceleration, however I would go a step further and use the kinematic equation. $a=\frac{v^2}{2d} = 283000 m/s^2 \approx 29000g$.
Comment: I Googled 2.38 km/s > MPH = 5,323.908 ; KPH = 8,568 I think we can rule out a wheels down landing as well.
Comment: You can land sideways and bounce a while, reducing velocity on each bounce. Furthermore you only need to shed about 1.6km/s, assuming you start in orbit.
Comment: @Polygnome By the time the MER got to the bounce, it was already slowed down considerably through aerobraking (it was designed for an impact speed of about 100 km/h, which are speeds we can handle safely quite easily). The same approach wouldn't work with the Moon, where you'd still be moving at orbital velocities on impact.
Comment: @Polygnome The bounce will either put you back on the route to Earth (if you're not in orbit around the Moon), or have the next bounce far away from the first one. Additionally, you're trying to design a spacecraft that can repeatedly bounce at huge relative velocities. I don't see how this could ever be practical.
Comment: @Luaan It was done at way smaller scale with the MER rovers, so its not entirely outlandish.
Answer: Yes, this can be done by using a circular magnetic track, like for a maglev train. A spacecraft should approach with low vertical and high horizontal velocity, landing on the short straight section like an aircraft on the runway.
For horizontal adjustment, the landing part could be shaped like a funnel horizontally and V shaped vertically, allowing some imperfections of the landing approach. If say 20 km length, we have 10 seconds for precise displacement. We can move the spacecraft hundreds of meters in this time under 10 g acceleration.
The "magnetic runway" should then guide the spacecraft into closed circuit track, like a toy railway. There it could run around as a proton in a particle accelerator, gradually slowing down. The possible deceleration force does not matter much as the spacecraft can then complete many loops of the circular track before it comes to halt.
The magnetic track must be strongly angled and actually more on the outer side of the track than above the ground ("wall of death"). It needs to provide enough force for keeping the spacecraft in a circular path. The necessary acceleration is $$a = \frac{v^2}{r}$$
Assuming we have a 2 km/s = 2000 m/s velocity and accept a heavy but human survivable 10 g acceleration, we only need a circular maglev railway with radius of $$\frac{{2000}^2}{100} = 40000$$
So 40 kilometers. It may not be easy to build but definitely not something that only supercivilization could do. If we opt for 400 km radius, we can simply use the existing todays technologies to land a train, not some tiny lunar lander, under just 1 g acceleration.
For a non zero descent angle, the landing funnel can be built on the side of a mountain, in the form of an arc-shaped ramp. For instance, the Mons Huygens is over 5 km high, so can embed on the side a ramp supporting the descent angle as high as 7 degrees.
The same system can be used also to launch the spacecraft.
This looks almost real: a landing strip of maglev track enters the turn inside a tunnel (source).

I do no think that any very special magnets or anything the like would be required very much above that today's maglev already possess. A simple model railway where a train levitates never touching any part of the track and staying stable when tilted can be built with permanent magnets without any electricity.
It is out of scope of the question how did the spacecraft arrived to the destination but there are ways of space propulsion others than a rocket.
Comment: My primary research deals with magnets of the size that would be needed for this approach. I can tell you that this approach doesn't work due to issues related to controlling the magnetic fields involved. Unlike in a particle accelerator, this machine would be handling substantial magnetic dipoles with substantial mass, and the field fluctuations for control would be enormous. Coupled with the inductance of the magnets, one could not achieve the speed of control necessary. This is an engineering issue unrelated to space travel, just thought I would enlighten based on my knowledge of magnets.
Comment: @NuclearWang but the lander itself doesn't have a thruster. The lander only needs a chunk of magnetic material and/or some passive inductor, so I think it meets the criteria of the question as asked.
Comment: Cool idea, but I'd argue it's still using thrusters. The thrusters are electromagnetic rather than chemical, and on the ground rather than on the spacecraft, but we're still using an apparatus that generates an external force to slow the spacecraft down.
Comment: @h22 Those models also have other correction mechanisms - most often, the model levitates, but it's also held in place through wires or strings. Static magnets alone aren't enough - they'll bounce you back off into space. It's basically the same problem as balancing a pencil on its tip.
Comment: @uhoh True, but by that criterion, it's acceptable to have a second probe with thrusters, have it clamp onto the first and perform a retrograde burn, and then detach from the first before it lands. The first lander itself has no thrusters, and needs no special apparatus to decelerate, but it seems like cheating to just move the thrusters to another object that's not *technically* part of the lander. This apparatus in this answer isn't materially different from the one I just described.
Comment: You do not need any "control" just for levitation: closer to the wall - closer to the magnets - stronger correcting force, automatically. I have seen models with permanent magnets without any electricity.
Comment: No, the model had magnets to keep the train above the ground and other magnets on the sides to prevent it sliding off the track. Once pushed by hand, the train ran circular track without any electronics and completely in the air.
Comment: Even apart from the "thrusters" on the ground, you still need "conventional thrusters" to get the lander precisely aimed onto the appropriate trajectory, with an *extremely* small tolerance for error.  The notorious unevenness of lunar gravity probably makes doing the aiming from the launch point impractical.  And besides, how do you aim a railgun launcher located on another planet or moon anyway?
Comment: Solar sails may work
Comment: @h22 no, solar sails probably won't work, as they are unlikely to give enough delta V to maintain aim once influenced by lunar gravity variation.
Comment: It does not need to be that precise. Assuming 40 km funnel - like entry part and 4 km/s velocity, we have ten seconds for the fine adjustment.  This is 250 meter displacement if for 10 g. The track must have side-driving force there.
Answer: I'm going to take a different approach here, which only makes sense in the context of repeated landings after we already have people or robot-like things up there.
Create a large lattice of materials on the Moon, then fire the lander at the lattice.
This is effectively like giving the Moon a localized atmosphere and using drag to slow the lander down. The advantage of doing this would be greatly reduced mass on the lander, since we don't need to launch a rocket with the lander, or the fuel for said rocket.
I've never done this, nor heard of it being experimented with, and can't speak to the feasibility of it. However, there's nothing physically preventing it.
One issue would be aiming the lander that well from far away. Normally, we get in the ballpark on the way over, then do a few course corrections as we get closer. And that requires thrust of some kind. But the Moon is really close compared to other planet-like bodies, so maybe we could pull it off.
But it would also require an ability to generate a lattice on the Moon with materials available there, which would likely require mining, smelting, and refining operations. So I doubt it's anything we'd be doing short-term, if ever.
If would also require a "heat shield"-like surface on the lander that could survive impact at those speeds, which might well require more mass than the rocket we're replacing. Some kind of carbon nanotube mesh for the lattice would spread the forces more evenly, requiring less shielding, but there's no way we could create that scale of mesh on Earth right now, let alone the Moon. Steel beams would be easier (not easy) to create on the Moon, but would require substantially more shielding since the impact forces will be very localized.
Note that iron and aluminum are both present in relatively large quantities at the Moon's surface, but carbon isn't, so steel might be out of the question, requiring a structure made of aluminum. See Wikipedia's article on Geology of the Moon for large-scale deposits. An Artemis Project article, Carbon on the Moon, says carbon is found at 82 PPM in the upper 1 to 2 meters of the ground. One ton of carbon would require smelting 12000 tons of surface material, but mild steel is only 0.05% carbon, so a ton of mild steel would only require smelting 6 tons of surface materal (just for the carbon -- you'd also have to get the iron somewhere). Doable, but maybe not feasible (especially if you can't get 100% of the carbon through smelting).
Comment: I might even add that you don't need to ship the impact material to the moon, just the building materials to hold it. I surmise that lunar regolith is a nice soft material, and given enough of it packed lightly (to keep density and cohesion down), we could just impact into the box of regolith. Still substantial acceleration, but can be handled by specialized electronics. Accuracy would likely not be an issue. We are pretty good at rocket science these days, even with inter-planetary transfers. We land inside smallish craters on Mars.
Comment: Set up a snowblower at one of the poles and make a big snowbank.  No, really!  (Okay, not really.)
Answer: I think you could do it with a rotating skyhook
The skyhook would be in a low lunar orbit, and the payload would catch the upper end at about escape velocity, or twice orbital speed. It's then swung down and backwards until it's almost stationary and released.
The tallest mountain on the moon is about 5km, so potentially it would have to withstand a 5km freefall - although I guess you could pick an orbit that avoids tall mountains and time it to land on a high plateau and 'only' freefall a km or two and crash at 50-100m/s, which still causes a few hundred g's of deceleration with a 10m crumple zone.
Or maybe the skyhook would unreel a tether of a carefully calculated length, detach the rover with millisecond accuracy and reel the tether back in before the next rotation...
Comment: @Camille - good question. A skyhook wouldn't need to be as precise as an ISS docking because it's not trying to make an air-tight seal between two hatches, but there's an obvious trade-off between accuracy and the weight of the link. I guess it could fire off some sort of harpoon from some distance but realistically a few small thrusters would be the lightest and most reliable way to do it. They'd only need a delta-V of a few m/s, unlike the 1-2000m/s required to land from orbit. Similarly, a bigger, more expensive skyhook would give more time there is to catch it and a gentler turn.
Comment: If the approaching spacecraft has no thrusters to finesse its approach to the skyhook, how big a target window can the skyhook move within?  How big is its "catcher's mitt?"
Answer: One option might be a penetrator -- a hard dart-shaped vehicle designed to hit the ground point first at 2.4 km/s and come to a stop in a few meters of regolith. The deceleration would still be severe but specialist electronics could be expected to survive it. The speed of sound issues mentioned above would be alleviated because the penetrator is made of something hard which will have a high speed of sound.
Comment: I missed the "rover" aspect. I think you can do a useful fixed scientific station this way, but it would be challenging to build something that could land this way and still "rove", I admit.
Comment: Even if the electronics survived, the rest of the rover wouldn't.
Comment: If the electronics survive the impact but the solar cells and cameras not, the rover ise useless. But what is the use of a rover burried under a few meters of regolith anyway? No light to the solar cells, no radio link. If the penetrator hits a point without a cover of a few meters of fine grain regolith it would be destroyed.
Comment: But how do you control the attitude of your hard dart-shaped vehicle without using any thrusters?
Comment: @Uwe: If the device doesn't pick up too much rotational momentum, reaction wheels should be able to provide attitude control without having to eject any material.
Answer: Some of the Ranger probes (including Ranger 3) to the moon had balsa-wood landers. Unfortunately, none of the ones that were working when they reached the moon carried them.
So we believe it's possible. It just comes down to how much crumple-zone you can afford to carry and how much impact you can stand.
Comment: Note that Ranger 3 did use a rocket to drop the speed from km/s to something under 44ms and question is asking about rocket free descent. Does provide an interesting data point on volume of padding needed even at that low speed.
Comment: related: [Puzzler - which spacecraft(s) incorporated real wood structural elements?](https://space.stackexchange.com/q/18856/12102) and also [What was the first piece of wood to reach the far side of the Moon? Or the first spacecraft?](https://space.stackexchange.com/q/33460/12102)
Answer: There is a way to land on the moon using less energy than it requires to reach Lunar orbit.  It requires a megastructure, but one that we have the materials to build today.
https://www.technologyreview.com/s/614276/a-space-elevator-is-possible-with-todays-technology-researchers-say-we-just-need-to-dangle/
Just dangle a rope down from the moon to (roughly) geosynchronous orbit distance from the Earth.
A ship would have to use thrusters to leave the Earth, but orbit is fast not far away.  The "rope" (skyhook) would be moving much slower than geosynchronous orbit; so a non-orbital trajectory -- a ballistic trajectory -- from Earth would work.
In theory you could even do a high-altitude balloon launch (to get past the atmosphere), then fire the package up to the moonhook.  Given perfect aim you could reach the moonhook with near zero relative velocity (the moonhook isn't in orbit, it is dangling; you aren't in orbit, you would be about to fall), grab the moonhook, then simply crawl your way up to the moon.
In practice you'd probably use thrusters to leave Earth and to refine your aim as you approach the moonhook, but nothing like actually landing on the moon.
Comment: @Quietghost Yes, it is a really tall tower up to L1, then a rope counter-weight on that tower.
Comment: I don't think this will work the way that you planned. Even if a rope was dangled from the moon down to roughly GEO, once the object crossed the moon-earth L1 point it would start accelerating toward the moon up to nearly lunar escape velocity. It would need a braking system of some kind, which includes a system to manage the angular velocity as well, since this is in a rotating reference frame (not the same as free fall straight down). This speaks to thrusters of some sort.
Comment: If you have the tech and materials to _dangle a rope from the moon_, it would seem to be a better idea to use it to build a pair of proper space elevators -- one from earth to GEO-and-a-bit, another from the moon to L1-and-a-bit.
Comment: @HenningMakholm See the link -- a moonhook is *trivial* compared to an earth-to-space beanstalk.  Beanstalks do not like being built on planets with as much gravity as Earth, and the fact that the moon orbits the Earth makes a beanstalk (aka, moonhook) there even easier, as it means you can counterweight using Earth gravity instead of Centripetal force.  A Centripetal moon beanstalk has a problem because of how slowly the moon orbits; a moonhook down past L1 fixes that.  Saying "you might as well build a beanstalk" is like "you can add, you might as well break RSA".


Are there any reasons for using SSL over IPSec?

Question: is it recommended  to use both protocols together? In which situation?
Comment: Sure. Say I am in a different country and don't want my internet traffic snooped on. I can use IPSec to tunnel the internet traffic back to a server in my home country. Once that traffic leaves that server in my home country it will no longer be encrypted. So I use SSL to connect to, for example, a web mail server.
Comment: I don't understand if you mean that from first country to my home the flow is encrypted with IPsec, and from my home to the mail server it is encrypted with SSL, or you mean that I use IPsec and SSL simultaneously from first country?
Comment: Well technically from the first country to your home the connection would be encrypted with IPSec and SSL. When it reaches your home country, IPSec is removed and only SSL remains.
Comment: @OP, It may be easier for a firewall-with-keys to sniff SSL  than IPSEC.
Answer: There are different layers of secure transport to consider here:

VPNs

SSL VPN (including tunnels)
IPSec VPN

SSL/TLS for individual services

IPSec vs SSL VPNs
Both SSL and IPSec VPNs are good options, both with considerable security pedigree, although they may suit different applications.
IPsec VPNs operate at layer 3 (network), and in a typical deployment give full access to the local network (although access can be locked down via firewalls and some VPN servers support ACLs). This solution is therefore better suited to situations where you want remote clients to behave as if they were locally attached to the network, and is particularly good for site-to-site VPNs. IPSec VPNs also tend to require specific software supplied by the vendor, which is harder to maintain on end-user devices, and restricts usage of the VPN to managed devices.
SSL VPNs are often cited as being the preferred choice for remote access. They operate on layers 5 and 6, and in a typical deployment grant access to specific services based on the user's role, the most convenient of which are browser-based applications. It is usually easier to configure an SSL VPN with more granular control over access permissions, which can provide a more secure environment for remote access in some cases. Furthermore, SSL/TLS is inherently supported by modern devices, and can usually be deployed without the need for specialist client-side software, or with lightweight browser-based clients otherwise. These lightweight clients can often also run local checks to ensure that connecting machines meet certain requirements before they are granted access - a feature that would be much harder to achieve with IPSec.
In both cases one can be configured to achieve similar things as the other - SSL VPNs can be used to simply create a tunnel with full network access, and IPSec VPNs can be locked-down to specific services - however it is widely agreed that they are better suited to the above scenarios.
However, for exactly these reasons, many organisations will use a combination of both; often an IPSec VPN for site-to-site connections and SSL for remote access.
There are a number of references on the subject of SSL vs IPSec (some of these are directly from vendors):

https://supportforums.cisco.com/document/113896/quick-overview-ipsec-and-ssl-vpn-technologies
http://netsecurity.about.com/cs/generalsecurity/a/aa111703.htm
http://www.sonicwall.com/downloads/EB_Why_Switch_from_IPSec_to_SSL_VPN.pdf
http://searchsecurity.techtarget.com/feature/Tunnel-vision-Choosing-a-VPN-SSL-VPN-vs-IPSec-VPN
http://www.networkworld.com/article/2287584/lan-wan/ipsec-vs--ssl-vpns.html

End-to-End Encryption
In some of the above cases, such as IPSec VPNs and SSL VPN tunnels, you may not be getting end-to-end encryption with the actual service you're using. This is where using an additional layer of SSL/TLS comes in handy.
Say you're remote and trying to connect to an internally hosted web application via an IPSec VPN. If you use the HTTP protocol via your browser, your traffic is encrypted whilst it is running through the VPN tunnel itself, but it is then decrypted when it hits the remote VPN endpoint, and travels over the internal network in cleartext. This might be acceptable in some use cases, but in the interest of defence in depth, we ideally want to know that our data cannot be intercepted anywhere between you and the actual service itself. By connecting to this application over HTTPS, you effectively have two layers of security: one between you and the VPN endpoint, and another travelling through that (between you and the web server itself).
Of course, this is not limited to HTTPS - you should equally employ other secure protocols like SSH, FTPS, SMTP with STARTTLS etc etc.
Comment: IPSec isn't just for VPNs though. You can use it between hosts
Answer: Here's a good article from cisco on IPSEC and SSL.  It includes strengths and weaknesses as well as an overview of each, and also implementing both of them together.
Comment: I'm not sure this is what the OP is looking for. He asks about using IPSec and SSL at the same time. This article is about using an IPSec VPN vs SSL VPN.
Comment: It talks about using both towards the end of the article.
Comment: The end of the article talks about why you would want to setup both an SSL VPN and an IPSec VPN. It doesn't talk about when you would use both at the same time. I think (though I could be wrong) that the OP is looking for use cases where you would use both IPSec and SSL at the same time.
Answer: It depends you may have corporate VPN Tunnel (that works on IPSEC) but a layer above the internal web server you are reaching over VPN in the corporate network might be HTTPS( which is via SSL)
Long back i did a talk on this
http://www.slideshare.net/sashankdvk/matrix-2768826
Answer: There are reasons for using both protocols.
When using an IPsec tunnel you would still want application level encryption. This is advantageous if there is a gap between the end of the tunnel and where your session ends.
The following diagram describes why you may want application level encryption like HTTPS (SQL in my example) in addition to IPsec.
<code>User => Website => IPSec Tunnel => Back End Network => SQL Backend
                                                   | => Data can be read by other hosts!
</code>
Comment: So isn't IPSEC making things redundant and slow?
Answer: It doesn't make sense to use both at the same time. Yes, IPsec tunnel "dissolves" at the edge routing firewall, but in the similar fashion TLS "dissolves" inside DMZ, usually HTTP server, i.e. if I am a hacker I would not bother with site-to-site network layer secured pipe nor TLS transport layer pipe from edge firewall to DMZ HTTP server.
Instead I would focus my efforts to attack HTTP-to-application server link. The only way to protect against that would be to extend the secure pipe all the way to the application, but neither TLS nor IPsec VPN can do that or is too cumbersome.
That leaves payload encryption and digital signing as the only choice, but in that case one needs only either TLS or IPSEC pipe, not both at the same time (for equivalent security and to meet performance targets). If payload (application) level security is not possible to implement, having both TLS and IPSEC pipe at the same time would not significantly increase the security, while at the same time it would significantly degrade the performance.
Answer: IPsec by itself does not secure end users (billions of them)—they do not have direct IP access outside the private network⟶they connect through ISPs.
(The upshot: If you're building a public-network end user application, you can't use IPsec.)
That is where TLS and others (eg SSH) comes in. They give end-user security in the face of ⨕ the growing list of entitled and ⨕ incompetent ISPs/governments.


Load Test and Stress Test in SharePoint 2010

Question: We need to perform the load test and stress test in SharePoint Server 2010.
How can we perform the tests and is there any automated tool to handle it effectively?
Answer: Today I've been looking at this very thing myself.  Here are some of the more useful links I've found.
I haven't tried this but it sounds interesting New SharePoint 2010 Load Test Toolkit Released.
As well Microsoft provides some guidance in Performance testing for SharePoint Server 2010
This article also contains lots of useful information and links SharePoint (Performance, Stress ) Load Testing
Answer: I used Load Runner to do load testing in 2007. Admittedly I haven't had to do it in 2010 yet, but I had a pretty good experience with Load Runner.
Answer: If you have Visual Studio 2010 Ultimate, the load testing suite is pretty amazing.


Playing Sax and Clarinet

Question: I currently play tenor sax but would like to pick up clarinet in the near future. How difficult would learning to play Clarinet be, given my experience as a tenor and long time piano player? How much will my knowledge of Sax help?
Answer: Disclaimer: I'm a fellow sax player and have more or less never blown into a clarinet.
As you probably know a clarinet does not have an octave key (it has a key which makes the clarinet jump to the fifth of the octave/twelfth instead). Because of that, you shouldn't expect fingerings between saxophone and clarinet to be related at all.
Other than that, I'm guessing your embouchure would be useful (at least in the medium — clarinets have a crazy range), as would your general dexterity and, obviously, your knowledge of music.
Comment: "Unrelated" is rather an overexaggeration.  The shift of an octave plus a fifth should be pretty simple to get used to-- practically like reading an alto part with a tenor sax or vice versa.   (disclaimer: I was a clarinetist who doubled on sax; but over the years I transposed Bb-Eb, Eb-Bb, C-Bb, A-Bb, Bb-A).
Answer: My sister in law was playing sax, but needed to switch to clarinet to be accepted in our wind orchestra, since the sax was well covered but we needed clarinets. She used about six months before she felt good enough to start in the orchestra (her instructor felt she was ready sooner).
Answer: Given that most of the reed players I've worked with bring sax (tenor/alto/soprano) and a clarinet and often a flute, leads me to say it won't be too much of a problem. SOME of the fingering is the same, and the embouchure is similar. Since you have musical knowledge from playing piano as well, it will be quite an enjoyable, straightforward job. I'm often surprised when a sax player does not also play a clarinet.
Comment: From what I have learned, the fingerings are more similar between sax and flute, than it is to clarinet.
Answer: Practice long tones on just the mouthpiece and barrel with a tuner at first.  You should produce a C# (concert).  Your embouchure should be firmer, but don't bite.  The chin should be stretched flat at all times and the jaw should never move. Basically: corners in, top lip stretched down, chin flat.  The "smile" embouchure should be avoided, as should any upward muscle movement.  (Think "in" and "down").
Once you are able to produce a steady tone consistently, start using the clarinet.  When you start working on clarinet, first stay in the low register, without using the register key. Start on open "G" and work your fingers one at a time all the way down the clarinet so you can get a feel for where the holes are.
After a few weeks, you might be ready to start using the register key.  An easy way to practice your tone here is to practice 12th exercises, fingering the nots in the chalumeau register and simply adding the register key.  Try the exercises here: http://www.clarinetcloset.com/upperregister.html  There are many other useful resources on this website as well.  Good luck!
Answer: I played tenor sax for years in junior high and high school band.  I learned several instruments in the interim, one of them being clarinet.  It was probably the easiest to transition to from saxophone, as the fingering and the embouchure are both pretty similar.  The mouthpiece is smaller, and so your embouchure will need to be a bit firmer/tighter than you're used to.  Given your long history with music in general, the learning curve shouldn't be terribly sharp.
Answer: I've only played Alto Sax but I've played clarinet for a while, so I might be able to help. It was really easy to learn saxophone with all my years of clarinet practice, so I figure the other way around is the same, too. You should have no problems making sound because saxophones and clarinets have about the same mouthpiece: very few differences. However the fingerings are COMPLETELY different, and you'll need to adjust. Also, the octave key on clarinet is really a twelfth key.
Hope this helped.
Answer: I played the clarinet first and had a go on the saxophone. I found the saxophone a little more difficult to control because I needed to relax much more. It's all about the embouchure.
Comment: similar for me. As a  clarinet  player trying out tenor sax, I found the low notes on the sax needed more coaxing / control than with a clarinet : whereas on a clarinet it was the very high notes (above top C, bflat clarinet)  which need coaxing / control
Answer: One little quirk is that the lower register of a B flat clarinet plays exactly the same notes as an alto sax with the same fingerings.  But the notes have different names!
So three fingers down is called G on a sax and C on a B flat clarinet but are actually the same note.
So sometimes I play sax parts on a clarinet, needing to think like sax.  It works OK until you go above the B/E and open the speaker key, at which point confusion reigns!
Comment: It's because the clarinet is 'in Bb', while the alto is 'in Eb'. They're essentially playing the same thing, but transposing, 'cos that's what they both do, but in different keys.
Answer: My dad (who passed away a few years ago at age 100) played so-called C=Melody Sax from before I was born till he was 90.  At which point he decided to switch to Clarinet.  He found the idea of a transposing instrument a bit daunting at first, but otherwise had no difficulties at all.  The switch from overblowing at the octave to overblowing at the 12th didn't faze him, nor did adjusting the embouchure.
I'm guessing you'll have no problems at all, especially since the Tenor and the clarinet both have the same transposition.  (Well, sort of.)
Answer: Clarinet and sax use basically the same playing technique.  The 'similar but different' fingerings are a very minor issue, don't get hung up on it.   You'll be OK.  Go for it, as generations of woodwind players have before you!
Answer: In my case I've played clarinet for about 6 years and although I'm still playing it. In my jazz class my instructor had me move to tenor sax and I gotta say it is confusing bc eventho the notes are the same and some of the fingerings are in fact the same. The confusion comes when you try to play a note say for example concert B flat. On the Clairnet its six fingers down with a alternative key while on the tenor sax it's only the middle finger down on your left hand.
For mouth position wise it is a lot different. On the Clairnet you tight the corners of your mouth to play while on tenor you need to drop your jaw. Without dropping your jaw the notes will play as though you are pressing the octave eventho you are not. It takes a lot of practice and learning a whole different way to play

Playing Sax and Clarinet


What is the best way to add co-inventor item in your CV

Question: I am a co-inventor in a filed patent. I want to properly mark this in my CV. As far as I can understand the concept correctly, first of all, since I am one of number of inventors I am a "co-inventor". Does that also makes me a "patent owner"? Also should I write the date it is filed AND the date it is granted/issued (is granted or issued the correct term)? I need to add the number of the patent when it is issued/granted right? Also the country, which in my case is France? Searched the Internet for a correct template but there got confused. Thanks for the clarification.
Answer: The first thing to do is understand what the terms mean. It is okay to call yourself a "co-inventor" on a patent application, just be sure you call a patent application an "application". You also need to understand that a patent application does not mean a patent will ever issue. It can take a few successful patents before you understand if you're likely to be successful or not, but the good news is that so few people ever have applications submitted that just getting that far looks good on your CV.
You don't have to list the owner on your CV. A patent demonstrates technical prowess and is your intellectual accomplishment. It may be obvious from the filing date who is the owner ("assignee"), but again -- this is your intellectual accomplishment, you do not have to list the employer.
The format I use is to have a section which typically has a heading like "Relevant Patents" or "Relevant Patents and Applications". I have a lot. I pick and choose which ones I put on my CV. I didn't look up the portfolio of the other respondent, but I've also use that format when I had fewer -- "Patents Granted". The other respondent may just be listing a few of theirs as well.
If this sounds like "it depends on how many patents you have and what else you can put on your CV", that would be correct. When I only had 2 or 3 patents, I merged my patents with publications. Then I had more patents and publications and made separate sections. Then I had a ton of patents, some publications and conference presentations I hated, and I became selective. You will want to look at how much different kinds of material you have. Three sections for "Patents", "Publications" and "Conference Presentations", where each section has one entry looks really sad on a CV.
When I interview someone who lists "Patents", I make sure the patents were actually issued, and I read the patent or application. Make sure you provide enough information -- title of the patent application, application or patent number, country where filed or issued. Your interviewer will likely want to see what it is you and your co-inventors came up with.
Best of luck with the patent application!
Answer: I have listed patents that I'm an inventor of on my CV. Unlike academic publications, I don't think there is specific format you need to follow. You don't need to state you are a co-inventor, just state you are listed as an inventor. List the patent number. If the patent hasn't issued, but an application has published, you can list the publication number. This makes it possible for the person reading the patent to look up the patent or application. If they bother to do this, they will see the other inventors and the application date. I list just the patent number and title on my CV. There is nothing keeping your from listing the co-inventors too, but since space on a CV is often tight, it isn't necessary. I suppose if the application hasn't published you might list a date, but I haven't. It is very common for the same invention to be filed for a patent in multiple countries. You could list each separately, but I only list one in the patent family (generally the US patent). For me this is in the interest of saving space. An example of what my CV looks like is the following.

U.S. Patents Granted (World and European equivalents not listed.)
9,222,886: Quantitating high titer samples by digital PCR
8,409,528: Apparatus and Method for Handling Fluids for Analysis
...etc...

Being an inventor and a patent owner are two different things. I have many patents I'm listed as an inventor on, but I'm the owner of none of them. In every case, the company that employed me is the owner (assignee) of the patent. This is the normal situation for patents that come about as a result of working for a commercial company.
Comment: So yes it is only filled at this point and it is not issued/granted. I am also in a commercial company, so it is the owner of the patent right? Not me? I am only a co-inventor. Where can I retrieve this publication number from? Maybe a french site for patents? I don't really know
Comment: @nmrlqa4 Applications typically publish 18 months after filing. Your company's patent lawyers might be able to provide an application number. Don't say you are only a "co-inventor", you are an inventor! Many if not most patents have multiple inventors.
Comment: I am not sure about the co-inventor thing? Should I really? We are group of 10 people. How should I know if I am an inventor or a co-inventor?
Comment: To be listed as an inventor on a patent, you should be responsible for at least one novel thing captured by the claims. Thus you are an inventor. Since the application hasn't published, you could list the application title and the full list of inventors if you want, but that takes a lot of space if there are ten inventors. If you want to use the term "co-inventor" you certainly can. What I was trying to convey is that you aren't "only" a co-inventor.  Ii your patent is granted, in my eyes that is just as impressive whether or not there are multiple inventors on the patent.


How do you know when a baby needs to be burped?

Question: My daughter just turned two, and over the last two years, I've learned a lot. Most parenting skills were easy to learn, but I never figured out burping when she was in the infant stage. In retrospect, I think if I had tried to burp her more often, she would have been more happy (with less crying). For future reference, when do you need to start burping, and when can you stop?
Comment: The real answer is that you will figure it out. Pay attention and observe when the kid is fussy. If there was recently a meal, try burping, and see if it helps. You will learn soon enough.
Comment: It could be that she was not much of a burper.  I felt like a bad mom because mine hardly ever burped when I tried to burp her.  Then another mom told me seriously that she generally had to whack her kid for an hour after his bottle to get a burp, and I thought, "Okayeeee... I'm not doing *that*!" and stopped worrying about it.  Interestingly enough, my daughter didn't really start burping until she was 6 or 7 years old. And she still can't burp at will.
Answer: Both my sons needed to be fed by bottle early on (my wife didn't produce enough to breast-feed). What we experienced was that if we didn't take a pause to burp in the middle of the meal, he would more likely gulp up when finished. So for us it was basically twice for each meal (one in the middle of the meal, and one after finished). It was not always easy to "produce" a burp, but it was worth it. We often saw that when we couldn't get a burp for some reason, it was likely that he would get some stomache ake later.
Comment: +1 This is a good rule of thumb. Always at the end, plus perhaps one in the middle.
Answer: With my son, we burped once in the middle and once at the end of the bottle and, with the exception of maybe once or twice, that was generally plenty.  By the time he was 7 months old, though, we could back it down to once at the end of the feeding unless he slowed down and seemed to indicate that he needed to burp.
With my daughter, who had reflux, it could sometimes be as often as at the end of every ounce if her reflux was especially active that day.  She is an exception, however, not the rule.
Comment: Yeah, I think after a month or so we figured out that he'd kind of slow down midway through the bottle and we'd stop, but then sometimes he'd spontaneously burp and he'd want the rest of the bottle.  We eventually just put two and two together.  He also spent a few days in the NICU when he was born, and they really pushed burping about halfway through the bottle though he didn't always need it and wouldn't always burp.  As he grew and ate more, the need to burp became more obvious.
Comment: So you just learned by trial and error that when he slowed down, he needed it? That's good to know.
Answer: Ours were breast-fed, but I got to feed them a bottle as the last feed before night-time sleep. They all needed a burp after that bottle.
Generally they got the whole thing down before needing a burp, however occasionally they would slow right down before finishing, and invariably a burp was all that was needed before finishing off the bottle.
Answer: My experience is that if my wife breastfeeds, my daughter has very little gas. She may need to be burped when switching sides.
The bottle gives my daughter more gas. I burp her a few times every feeding. If she gets squirmy, that's her telling me that something is uncomfortable. But each child may exhibit different signs.
Answer: With my daughter, I burp at the end of every bottle, or if she starts becoming fussy at the nipple I'll burp her then too (to make room for more). She tends to drift off when she's sated, so if she's fussy she's either in gas distress of some sort or we've been trying WAY too hard to get her to take a bottle she doesn't want.
When burping, I'll generally use a flat open palm with curled fingers (providing a relatively flat, not-floppy surface) and pat firmly about twice to three times a second. If a few minutes of this does not result in a pretty audible belch, she didn't suck much air when she was feeding (certain bottles are better at this than others; we've generally had good results with the Playtex VentAire series. It's all about nipple shape, proper flow for your baby's age, and preventing air mixing with formula as the pressure in the bottle normalizes) and I don't worry much about her not burping.
Sometimes, I will also leave her in a reclined position after feeding for a few minutes. Not enough time for bubbles to enter the intestines and become gas, but enough time for the bubbles to consolidate towards the top of the stomach. This generally reduces spit-up in my experience, while giving that satisfying belch that lets me know she's got it out of her system.
Answer: For the record, both our midwife and paediatric told us to put the baby on the breast, facing us after each meal. We should gently pat her on the back a couple of times. We should not wait for her to burp but pat her a only couple of times. Our daughter usually burped very quickly, but the advice was specifically not to try too hard to get a burp; if she needed, she would burp.


Will JavaFX work on Android?

Question: It would be a shame if it doesn't, because it will make for more attractive looking Android applications.
Answer: Not right now, and it would be a nontrivial task to make it work. Android doesn't have all the libraries that the typical desktop JRE does. Although since Android is open source and it will run anything that can be compiled to Dalvik byte code, it's not impossible.
Really, I don't really think JavaFX will make for more attractive looking Android applications - the most important thing is how integrated the application is into the hardware and the Android display framework has a lot of stuff to make that easier.
Answer: JavaFX 2.0 is now a library. The implementations are platform specific because, amongst others, of the use of hardware accelerated graphics. There's a version for Windows (that uses DirectX) and a developer preview for Linux and Mac (which uses OpenGL) : oracle
Because of the heavy use of hardware acceleration, I guess if there will be an android version (very likely), the target will be relatively new tables, rather then all android devices.
Answer: Perhaps it's not so important the attractiveness. I think portability matters a lot nowadays, and this kind of tech makes it very portable.
Answer: Please go through below link : openjdk , oracle

Will JavaFX work on Android?


Could this cracked drywall be caused by a shifting house?

Question: We are in southern Illinois and last Sunday my wife noticed a crack above the kitchen cabinets. We started looking around and have found cracks all over the house in different areas that were not there before. We are starting to see seams in the drywall in different place and nail/screw heads through the drywall. The paint is pulled in many places along where the walls ceilings meet. The windows are out of square (were not before). And almost all the trim in the house is pulled away from the ceiling. We have paneling in one room and it has pulled away in the corners. The wall behind the fireplace has started to pull away from fireplace. Gap gets bigger as you go up. Would this be shifting? Worried because this has all happened in a weeks time. Here are some pics.
Comment: Are you sure all of this has happened over the past week, and you're not just noticing things that have been there because you're looking for them? From the pictures, it looks like most of this is not active (e.g. it looks like most of the cracks have been painted over). I'm not there to look, so you'd know better than me. But if a 30 year old house is suddenly developing cracks (settling), there is a major issue and you should have engineers there ASAP.
Comment: @Mark Like I said, I'm not there so you'd know better than me.  You should make some urgent phone calls, and get somebody there soon. A 30 year old house suddenly shifting, is never a good thing.
Comment: Your pictures are not publicly visible.  Have you checked the foundation for cracks?
Comment: How old is the house?  How long have you lived there?  Do you have a basement or crawlspace?  Are there cracks anywhere in the basement or foundation?
Comment: House was built in 79 or 80. We have a crawl space. I crawled under the crawl space a couple days ago and there were a few cracks but nothing that stood out.
Comment: Lived here for a little over a year
Comment: There were 3 cracks that I know was repaired. One inside wall was paneling and we put dry wall before we moved in(was may of 2011). So nothing on that wall for sure. Also positive trim was not pulling away. Other cracks are in places were you would not miss. In master bedroom  on the wall facing the bed. In the dining room across from table were I sit. The paint pulling or pushing together is all around master bath and other areas.
Comment: Not saying somethings might not have been there. But Sunday night Monday morning we looked all over the house for other things to get an idea of what was going on. We have 2 windows in our master bedroom. The trim on one was not square corners sticking up a good quarter of an inch. Pointed it out to my wife and used the other window as example. It was square all the seams tight. A couple of days later it is no longer square and seams are not tight. The trim I know was not coming down repainted 2 of the rooms with trim in it.
Comment: Understand I have made calls and trying getting ready to make some more to day. What type of engineer would you call? Called some one for foundation but can't be here for a week and a half.
Comment: Though it is an old thread, Mark, did you find out if it is a foundation problem and if so, how much did it cost ? I am seeing similar cracks in our new home (1960 built) .
Answer: I've encountered the same problem in my own home, although the drywall and ceiling seam cracks only showed up one at a time over the course of a few years, and most of them were present when I moved in. If more than one or two seams popped or nail heads started showing within a month, that seems like it could be a rather large settlement in your foundation, or some other structural problem.
I'd highly recommend getting a foundation specialist to your house sooner rather than later to see if your foundation might need piers to support part of it, or if some other repair is required. In my house, a total of 14 piers were needed along the side and front of the house to support one side and prevent further shifting. There were a few hairline cracks (even small cracks can be a bad sign depending on where and how many they are) in the foundation walls, and the corner of the house had settled over 2" before the problem was found.
The problem could also be in load-bearing structures (walls, I-beams in the basement, etc.), especially if it seems the problems are mostly towards the middle of the house.
The sooner you get this fixed (don't just let it go, even if you have to pay a few thousand), the better. You'll avoid more drywall repair later, and prevent further settlement and degradation of your house's structural integrity.
Comment: Yikes! See if any neighbors are having similar issues. Could be a drainage issue related to recent storms/snow melting (I'm in St. Louis, so I know you probably have had a bit of extra precipitation recently, as I have). Hopefully there isn't an underground stream or something dumping water under or near your house.
Comment: Have a company coming out to look at the foundation but they can't be here until the 19th. I just never saw anything like this. The main structure of the house is 63 feet long and 24 feet wide with one end going to 32 feet wide. And there is damage in every room. And more damage is accruing everyday. The main bathroom had no damage when we started seeing stuff on Sunday night but by Tuesday night you could see problems in the bathroom. We found one window out of square Sunday night and now every window is not square.
Comment: Talked to neighbors and nothing there...lol one thought I was making it out worse then it was so I gave them a tour. We are at the bottom of a slight incline but the people we bought the house from put all new drainage around the house so even the water from the gutters go into drains taking it away from the home. When I went under to check foundation it was dry. Maybe a little damp in some place but not enough that I was muddy when I came out.
Answer: Have you checked at your water meter to see if it looks like you are consuming an excessive amount of water? It could be that your under ground water feed into the house has sprung an underground leak near, under or within your foundation. Being under ground it is possible that it could run leak for a long time and you would never casually observe it. A steady flow of water into the ground in such condition could lead to a serious settling problem such as you describe where many things could change quickly over a short period of time.
This should be easy to check. Write down the reading from the water meter one evening and then check it again the next day. Of course allow for a nominal amount of usage for toilets, a shower and your drinks.


CKAN database scheme

Question: I'm doing some research and I would like to learn how CKAN manages data, in particular, I would like to learn its database scheme.
Do you know where I can find it?
Comment: Probably, you will find the answer in the official github of CKAN. https://github.com/ckan/ckan
Comment: The links in the answers are broken. And the question is about 4 years old. Is there any update to CKAN database scheme? Come on, some tables cannot be so hard to draw an entity-realtionship model of.
Answer: CAVEAT: I am not an experienced user of the CKAN software.
From reviewing the online documentation, it appears that CKAN supports storing data in two methods: FileStore and DataStore. FileStore is storing and retrieving an entire datasets (e.g., CSV file, PDF document, etc). It does not involve a database.
The Datastore uses what they call an ad-hoc database for storing and querying individual elements of a structured dataset. In one mode, it appears to be fairly generic, creating a table and entries based on the column names in the structured data, and supporting an API query based on the column names.
http://docs.ckan.org/en/1117-start-new-test-suite/datastore.html
I believe it has more advanced capabilities and relationships in the structured data is linked data or RDF and is constructed using a vocabulary supported by CKAN, which include the Dublin Core, DCAT, VoID and SCOVO.
http://docs.ckan.org/en/1117-start-new-test-suite/linked-data-and-rdf.html
Comment: This file is probably closest to what you're looking for: https://github.com/ckan/ckan/blob/master/ckan/logic/schema.py Otherwise, you can just install CKAN, run its migrations, and then dump its database schema.

CKAN database scheme


What are the differences between an investment mortgage and a personal mortgage?

Question: I am researching purchasing a three unit brownstone in Washington DC to serve as a rental. I am comfortable with my understanding of a personal mortgage, but don't fully understand how an investment mortgage works. What are the differences between the two?
Comment: It would be helpful to know if you intend to occupy one of the units for a couple of years.
Comment: I was thinking about living in one of the units and renting out the other two.
Answer: Banks consider investment mortgages (and any mortgage where you don't live in the property), as a riskier investment than an owner occupied, home collateral mortgage. The sources of increased risk range from concerns that you will screw up as a landlord, your tenants will destroy the place, you won't have tenants and can't afford to pay the bank, and/or you'll take out several other investment mortgages and over extend yourself. All of these risks are compounded by the fact that it is harder for the bank to convince you to pay when they can't put you out on the street if you default. Banks lend and invest in money, not real estate, so they would much rather have a paying loan than a foreclosed house, especially with the modern foreclosure glut.
The increased risk means the bank will charge higher interest for the loan, may require a higher downpayment, and will require higher lending standards before issuing the loan. A new housing investor can get around these higher prices by living in the home for a few years before renting it out (though your lender could possibly require you to renegotiate the loan if you move out too soon).
Comment: It's also good to know if you live in the area. The bank probably won't consider that a risk factor, but you can take better care of an investment than a disinterested management company will.
Answer: According to my wife who used to work in the industry, since an investment mortgage is more likely to fail (they are just riskier) there are higher loan to value requirements and higher interest rates.
They are just different products for different situations.
Answer: I used to own a few investment properties, so I'm pretty familiar with this.  As MrChrister mentions, lenders see investment mortgages as higher risk. People who fall into financial trouble are much more likely to let their investment properties go than their personal residence.  Consequently, the interest rates and downpayment requirements are generally higher.
Typically a mortgage for an investment property will require 20% down, vs. as low as 3-5% down for a personal residence.  With excellent credit and some shopping around, you could probably do 10% down.  Interest rates are typically about a half-percent higher as well.
You'll also find that the more investment properties you have, the harder it becomes to finance new ones.  Banks look at debt-to-income ratios to determine if you are over extended.  Typically banks like to see that your housing payments are less than 20% or so of your income.  However, with rental properties, housing payments generally account for far more than 20% of your rental income.  Other income you have can offset that, but after buying 2-3 houses or so, your DTI generally creeps into the range where lenders are uncomfortable lending to you anymore.  This is why you'll find that many rental properties are bought on land contracts with owner financing rather than with mortgages.
Comment: The part about the ratio of housing payments to income surprises me. If your mortgage payment for a given rental unit is $800 and you collect $1,000 rent - that's 20% profit and a very nice margin. But it also means that your housing payment for that unit is 80% of the rental income and spells trouble according to what you describe.
Comment: @Doug - that's correct, but lenders tend to look at as your total income vs. your total debt, and don't consider the investment properties separately.  In the scenario you describe, your income would go up $1,000/mo but your debt payments would go up by $800/mo.  Depending on your income and other debt, it doesn't take many properties to push your overall DTI over the 20% threshold.
Answer: It's just a guess, as I'm from the UK and am unfamiliar with the term "investment" mortgage but is it one where you are buying the property in order to rent it out, and make money from it, rather than to live in?
In the UK we call those "buy to let" mortgages and one of the main differences is that you have to have a higher deposit to get that type.
Answer: If you are going to live in the house for awhile, you can probably use a regular mortgage. Shop around and look for a mortgage program that works. Look at local banks/credit unions, particularly those with community development programs.
Usually an investment mortgage is higher rate, higher payment and has higher underwriting standards.
Comment: @Ryan - Typically banks will allow you to count 75% of expected rental income when qualifying.  So if your personal income + 75% of the expected rents gives you enough income to qualify, you'll probably be OK.  If you would consider living in one of the units though, then duffbeer's answer might apply.
Comment: I'm looking to purchase a small multi-tennant building. Here in DC those run between $1M and $1.5M. I know for a fact I don't qualify for a one million dollar mortgage on my personal income, but with the help of tenants it's possible.


Integral of a quadratic on a polygon (variations of discrete surfaces)

Question: This question is pretty simple to state: given two linear functions on a polygon, I'm looking for a formula for the integral of their product which depends only on the values at the (unlabelled) edges and on the shape of the polygon. However, the motivation comes from a problem I've been investigating for a while, so I thought I might as well elaborate for the sake of context (the previous question in the series is here). My understanding of the problem is gradually progressing, and with it the way in which I formulate it. Quick recap:
I'm interested in variations of piecewise linear surfaces in ℝ3 (which need not be triangulated). Fixing the "combinatorial type" of a surface - i.e. the way vertices, edges and faces are joined together - I have found that the space of variations has dimension E + 3χ, with E the number of edges and χ the Euler characteristic. For surfaces homeomorphic to a sphere, we get E+6 with 6 dimensions corresponding to translations and rotations.
I would like to find an inner product on the space of variations, with the following caveat. There are operations which change the combinatorial structure of a surface but not its actual shape - such as adding a "flat" edge across a non-triangular face, or an edge of zero length at a vertex where more than three faces meet. In such cases there is a natural inclusion of the variations of the original surface into the variations of the new one, and I would like my inner product to be preserved under this inclusion.
I've been proceeding by analogy with the smooth case: each variation induces a unique normal vector field on every face, so we can take the pointwise product of these and then integrate. This inner product is intuitively consistent in the sense described in the previous paragraph.
Because variations must preserve linearity of the faces, the vector fields are linear on each face - so we can write them, and their product, in terms of the vertices or edges. In particular, for a triangular face the inner product is the average of the (pointwise) products on the centres of the edges, multiplied by the area of the face.
This is promising: for triangulated surfaces, I now have an expression which depends only on the edges. But I'm having trouble extending this to non-triangular faces. I've tried triangulating a polygon in various specific and generic ways, and so far all I've got is a mess. But maybe I'm being stupid. Any suggestions?
Comment: http://en.wikipedia.org/wiki/Green's_theorem ?
Answer: Let's say that your polygon is $P$ and that $\xi$ and $\zeta$ are two linear functionals, is the integral you are looking at
$$
Q(\xi,\zeta) := \int_{x \in P} \xi(x)\zeta(x)  dx ?
$$
If so, $Q(\xi,\zeta)$ is the moment of $P$ with respect to the pair of lines $\xi = 0$, and
$\zeta = 0$ and $Q$ is (up to a multiple) the quadratic form that defines the Binet ellipsoid. There is a large body of literature on this, but perhaps Routh's book http://gallica.bnf.fr/ark:/12148/bpt6k997227 is a good place to start.


Determining the paleoelevation of mountain ranges

Question: In New Delhi, a lot of people say that the
Aravali range  used to be as tall as the Himalayas. How do scientists know that some mountain range used to be a lot taller millions of years ago, and what is the process by which mountains erode in general?
Answer: I'll begin with your second question, as to how mountains erode.
To simplify things, there are two methods:

Physical weathering, where the rocks are broken down by weather. For example, there are cracks in rocks that get filled by water which freezes and expands. This maker the cracks bigger and breaks down the rock. Also wind, earthquakes and any other process that breaks it down.
Chemical weathering, where the rocks are not broken by are altered to softer and weaker types of "rock". For example, take granite, a common rock in mountain ranges. It contains minerals from the feldspar family which are solid and hard. However, give some time and water and they convert to minerals from the clay family (aka "dust").

The first process is more relevant for tall mountains.
Now, how do we know the rate? This is a competition between uplift (the rising of the mountains) and the weathering (the breaking down of mountains). I'll give one example to illustrate it. Let's say that on the mountain top you find limestone with a certain fossil that you know existed 5 million years ago. So you know this used to be at the sea floor, let's say 300 meters below the water, but now it's 2000 meters up in the sky. So it had to rise 2300 meters in 5 million years. You can calculate the average uplift rate from that. Also, let's say that you know that in the past 10 years, a certain amount of rock was eroded from the mountain. You can calculate the rate of weathering. This way you can know the total rate.
There are new modern methods which rely on cosmogenic isotopes to get a much more accurate picture of this process, but that's for another question.
Comment: See below for why this answer is incorrect.
Comment: @KnobScratcher actually, no. Details in comments to your own answer. While your answer covers part of the story, it does not invalidate mine, and I really don't understand the down vote.
Comment: Your stated technique is so unreliable, that even with recently uplifted  fossils, isotope geochemistry (at the very least) must be used to put constraints on the position of sea level over time.
Comment: @KnobScratcher are you ignoring the words "example", "average" and most importantly "new modern...isotopes...more accurate" that all appear in my answer? The OP is obviously a non-specialist and a figure like the one in the other answer may be too complex. A simplified answer that one can easily visualise in their head is what's required here. Enjoy life.
Answer: Determining an uplift rate for rocks is not easy, but certain techniques will produce far more reliable results than others. There are also qualitative techniques that provide estimates so rough as to be almost useless. For example, this technique, from the 'answer', above:

So you know this used to be at the sea floor, let's say 300 meters
below the water, but now it's 2000 meters up in the sky. So it had to
rise 2300 meters in 5 million years. You can calculate the average
uplift rate from that.

...fails to account for the time this sediment spent lithifying, or "turning into stone" which would certainly have involved deep burial for some unknown time, at an unknown depth, yielding an upper, or lower bound on no more than a wild guess.
Uplift rates of basement rocks (mountain cores) are best quantified using "fission track dating"; a thermochronometry technique whereby the helium track lengths, produced by the radioactive decay of uranium into thorium, are analyzed. The technique depends on careful selection of appropriate mineral crystals, within the host rock, containing radioactive elements. Even this technique requires understanding an uncertain history of annealing temperatures. For example, in this paper:
Exhumation of basement-cored uplifts: Example of the Kyrgyz Range quantified with apatite fission track thermochronology
the following figure illustrates the complexity of the problem:

Schematic illustration of the affect of differing total annealing temperatures (Ta) on complex cooling paths. The four vertical elevation profiles represent a sequence of exhumation (cooling) and burial (reheating) events. (top) Evolving temperature history and (bottom) distribution of apatite fission
track ages in a vertical profile at the corresponding time step. Each profile shows the cooling path of apatites that are more (solid line) and less (dashed line) resistant to annealing. The base of the partial annealing zone (PAZ) for each type of apatite is considered to be the respective Ta. Exhumation and
burial events are (unrealistically) depicted as instantaneous for clarity. The geothermal gradient is assumed to remain constant and advection of isotherms is neglected for simplicity.
The above paper is an excellent analysis of the history of uplift of the Kyrgyz mountains, in which constraints were made on the age of uplifting as the range grew laterally. Mountains don't just grow vertically!
Comment: _fails to account for the time this sediment spent lithifying, or "turning into stone" which would certainly have involved deep burial for some unknown time, at an unknown depth, yielding an upper, or lower bound on no more than a wild guess._ and your answer fails to account for it as well. Also, what if the rocks were lithified to begin with? Also, uplift rates are not _best_ quantified, but it's one of the methods. Other methods include cosmogenic isotopes (which I mentioned) and a variety of other methods, not all geochemical.
Comment: Fission track dating results in thermochronologic data: i.e. time and heat. Heat does not always equal burial depth. Again, this in conjuction with other method can provide uplift history of the rock. There's also the requirement that suitable minerals are actually present in the rock. What if you don't have apatite? Tough luck. Another thing that your answer completely fails to address is the erosion rate, which is not equal to the uplift rate and is critical to the overall paleoelevation of mountains, which is exactly what was asked in this question.
Comment: Regardless of the problems I just outlined, I will upvote your answer because it shows another aspect of the anwser that was not addressed in mine. However, it is not the only answer, and together with my own answer provides a more complete answer to the question asked by OP.
Comment: I didn't address erosion rates because without so much as a basic understanding of uplift rate, there can be no sensible calculation of erosion rate, and thus mountain elevation over time.


Writing Sound for a movie

Question: Hi. i would like to know if there is any particular format for WRITING sound for a film. I am working on a film with a friend and he handed over me the script and it just put me in a fix. I have made out a list of basic sounds that i might use like the ambient sounds, birds chirping, crowd etc etc. but i am not sure about how to go about the script. This is the first film that i am working on. Its a part of my college project. it would be a great help if i would know a format that sound designers follow to give the movie a particular sonic personality.
Answer: Hi, I don't know about any formats. Randy Thom actually started a project/discussion on the 'sound-article-list' @ yahoo groups.
But from my experience, the best thing to do is to sit down with the director and talk about the way he feels it should/could sound. You will most likely run into unconceivable sound concepts.
I remember a animator/director asking for an 'emphatic' sound. I explained to him that this was an impossible assignment, unless he could help me visually. After going through all his ideas, my vision of the sound design was much clearer. I was able to visualize this to him just by explaining in 'normal' language.
I never handed him a written sound design, but he did have a good idea about what it was and adapted his script to make things better sound wise.
So best thing to do is first listen to the director, try to distil a design principle out of that and work yourself down the script with him. Keep communicating and stay open to ideas, this will get you closer as a team and helps the project.
Good luck!
Answer: There is another format the script can take and it is called and AV script.  Celtx (free script writing program) has a mode for it.  Check out this video http://www.ehow.com/video_4442031_learn-av-script-editor-celtx.html
Also, google image search AV script format to see a visual.  Basically you draw a line down the page and the shot description goes on the left and the audio description goes on the right. The AV script can describe the exact shot and at the same time tell what the characters are saying.
See if your director is willing to adapt the script to this format.  It will not only help you and the director discuss sound before you get to work the the film but it will also help him talk through the film with his camera person and editor.
If the director is not interested in adapting the script, splice up the script you have into the descriptions and dialog and then add in the sound design descriptions on the audio side as needed.
Answer: David Sonnenschien has done a lot in this area of putting together paradigms on how to attack a script for sound design. I find his ideas very useful when dissecting a script into emotional, transition, environmental areas of the film and helping me build a sonic philosophy around the narrative. Great stuff. Also, Randy Thom has a great essay on filmsound.org which discusses the importance of how to emotionally and theoretically wrap your head around a script in preparation for a sound design.
With the ideas existing in these pieces, I have been able to improve on my verble interpretation of a script when consulting with the director and other members of the sound crew.
I hope that this answers your question.
Answer: Everyone works differently, so this is just my opinion. And I do a lot more work that is artsy fartsy and am called upon much more for designing original soundscapes and fx, rather than working with or mixing the "normal" sounds of a film. I've never done any dry dialog, ADR or anything like that. Never done anything with much of a budget either.
So that said, I've never had much luck with a script alone. I'd always prefer to have the writer and/or director of the work give me their vision of it in plain English, and any notes they feel are important, and just start brainstorming from that. At that early stage, it's probably beneficial to also make notes for the "boring stuff"; incidentals, interior, exterior, scene ambiences etc. All you can really do is prepare some "maybes", as I call them. Stuff you already have that might come in handy in the scenes you know about.
Beyond that, nothing beats sitting down and watching footage with your own eyes, in my opinion. I've never seen footage that really looked anything like it did in my head as it was being described to me or as I read a script. That's the problem/beauty of human interpretation. Hopefully the director gets things shot that look the way they see it in their heads though, that's the important part. So, in a nutshell, I pretty much design/compose sound to picture in realtime, one scene at a time.
It's probably a very slow way to work. I'm sure that folks who work with major motion pictures etc have some much more valuable workflow tips to share.
Answer: @britt. thanks for the link .. i have downloaded celtx. the way that i have started working is i have started recording basic sound samples scene wise and am making the director listen to them as i am proceeding. plus also jotting down the scenes where the director wants me to use sounds that have a SPECIFIC character.

Writing Sound for a movie


How to translate menu items?

Question: Is there a way for the menu to be translated when I choose the website language? Does anyone have a solution to do it without using the plugin?
Comment: I recently wrote code which switched between two different menus depending on the language the user was browsing in. It wasn't that easy! A plugin might help, but I couldn't recommend one from experience. I know WPML is popular, might do what you need...
Answer: You can create a menu use another language. Then you use conditional code to switch the menu. or you can use title attribute of menu.
if($language=='us'):
wp_nav_menu(menu1);
else:
wp_nav_menu(menu2);
endif;

Answer: you could use Polylang plugin which will create different template for each language, and integrate different menu for each language.
start reading here and dig in: https://wordpress.org/plugins/polylang/
Answer: I just wrote a simple hook to use the normal translation functions, which I just added into my theme's functions.php file.
/** Translate menu items. */
function translate_menu_item_frontend($item_output, $item) {
    if (property_exists($item, 'title')) {
        $parts = explode('|', $item->title);
        $context = count($parts) > 1 ? $parts[0] : null;
        $text = end($parts);

        return preg_replace(
            '/(<.*?>).*(<\/.*?>)/s', '$1' . _x($text, $context) . '$2', $item_output, 1);
    }

    return $item_output;
}
add_filter('walker_nav_menu_start_el', 'translate_menu_item_frontend', 20, 2);
add_filter('megamenu_walker_nav_menu_start_el', 'translate_menu_item_frontend', 20, 2);

This means you can, for example, set a menu item navigation label to 'Home' and it will be translated with the builtin core translations. You can also specify a context separated with |, so for example 'Theme starter content|Contact' would use the builtin core translations for the word 'Contact'.
This can easily be adapted to support custom domains if you want to provide your own translations too.
Comment: On a related note, if you want the site to automatically change language based on the user's browser settings, I wrote a small plugin for that here: https://wordpress.org/plugins/preferred-locale/

How to translate menu items?


Any way to reply to a bunch of people in the comments?

Question: I've posted a question and 4-5 people have given me good pointers, and I went back and tried to work on their pointers. It does not work as I expected, Now I want to reply to all in one comment saying that I tried this this this and it did not work. Why does SO stop me from doing that?
Comment: Because you should not be able to spam everyone in a comment thread; by limiting you to *one* name per comment you are also rate limited by the 'at least 15 seconds between comments' rule.
Comment: You could edit the question to add the various ideas and the results. That would make the question more complete.
Comment: @MartijnPieters You have a very good point. But, If i have to spam, I'd create multiple comments anyhow. that would be a good feature from my point of view.
Answer: I agree with @PatriciaShanahan's comment to your question: you should edit your question to reflect the solutions you tried and the results of those attempts. This helps future visitors understand the problem better.
Providing feedback to individual users can be useful, but what you really want is to ask the community for additional help, which is what questions are for.
Comment: Note also that an edit will bump the question back up to the front page, so it will still get exposure after the edit
Answer: I think this might stem from a misunderstanding as to what purpose comments serve.
They're second-class citizens, only really meant as a way to gain more information/insight into the problem, as opposed to a lite forum in which one is going back and forth with others, giving feedback/info on the question.
Your question should be able to stand alone, and this includes anything new that you've tried that's been exposed in the comments through requests for clarification.


Joseph and Chanukkah

Question: The Parshiot about Joseph always fall right before or during Chanukkah.  It their a relationship between the Joseph stories and the Chanukkah stories?  It there something to be learned from the fact that they are so closely linked together?
Answer: Rabbi J B Soloveitchik writes that "Joseph wanted to be powerful in a political sense, to attain wealth and prosperity, .....; but he also wanted to be great spiritually, to be loved .... by people because of the greatness of his wisdom and his kindness."
"Apparently, Joseph thought that he could combine both. This is the meaning of the ketonet ha-passim—multicolored, not monochromatic, not one monotonous color."
"That synthesis is exactly what the Hasmoneans stood for. They were excellent warriors, but the very moment they laid down their swords, their interests centered around kedushah, holiness, around the oil for the menorah which burned in the Temple, of "purification of the entire Temple and the dedication of the altar" (II Macc. 2:19)."
Answer: Off of Aish's website:

Chanukah is commonly viewed as a celebration of the Jewish People defeating the army of Antiochus and reclaiming political, along with spiritual, sovereignty. What is less well known is that Chanukah also highlights a delicate interplay between conflicting emotions, attitudes and intentions that that are expressed both in interpersonal relationships and in one's relationship with God. The pathway to unlocking Chanukah's hidden message leads us through the Torah portion Vayeshev, which is typically read on or immediately before the holiday of Chanukah.
...
A parallel can now begin to be drawn to Chanukah. The assault of Antiochus on the Temple is viewed by many as being the outward manifestation of a more insidious invasion -- that of Hellenistic ideals into the minds of practicing Jews. Faith and belief were replaced by empirical rationalism. The pursuit of physical pleasure no longer served as an instrument of spiritual health; it became an end unto itself. The concept of God was both splintered and reduced from a unique, transcendent Being, to a pantheon, decidedly human in character. By the time Antiochus defiled the Temple, Jewish sensibilities had themselves degraded and lost their clarity.
...

That is only a snippet of the article.

Joseph and Chanukkah