WORK Site Topo Crack
The high alpine meadows of Yosemite National Park contain huge granite domes. Because of the higher elevation, climbing in Tuolumne is perfect to get away from the heat (and crowds!) of the Valley. The clean domes are the perfect place to work on your slab and crack climbing skills.
WORK Site Topo Crack
Many living tissues achieve functions through architected constituents with strong adhesion. An Achilles tendon, for example, transmits force, elastically and repeatedly, from a muscle to a bone through staggered alignment of stiff collagen fibrils in a soft proteoglycan matrix. The collagen fibrils align orderly and adhere to the proteoglycan strongly. However, synthesizing architected materials with strong adhesion has been challenging. Here we fabricate architected polymer networks by sequential polymerization and photolithography, and attain adherent interface by topological entanglement. We fabricate tendon-inspired hydrogels by embedding hard blocks in topological entanglement with a soft matrix. The staggered architecture and strong adhesion enable high elastic limit strain and high toughness simultaneously. This combination of attributes is commonly desired in applications, but rarely achieved in synthetic materials. We further demonstrate architected polymer networks of various geometric patterns and material combinations to show the potential for expanding the space of material properties.
a Existing elastomers and hydrogels (equilibrium-swollen in water) exhibit a negative correlation between two properties: elastic limit strain and toughness. The TPNs synthesized in this work simultaneously achieve high elastic limit strain and high toughness. b In a fascicle of an Achilles tendon, staggered collagen fibrils are embedded in a proteoglycan matrix. c Schematic illustration of TPNs. Hard blocks adhere to a soft matrix through topological entanglement of polymer networks. d Mechanical principle of a staggered-patterned TPN for high elasticity and high toughness. e TPN hydrogels prepared by sequential polymerization and photolithography.
The soft and hard phases must adhere strongly. Interfacial adhesion is the critical challenge for the design of composite materials. We attain strong interfacial adhesion by topological entanglement of polymer networks. The strong adhesion helps to smoothly transfer the stress between the phases. In all the mechanical measurements of TPNs, we have not observed any interfacial fracture.
TPNs further expand the space of material properties by geometric patterns, material combinations, and multilayers (Fig. 4). TPNs of various patterns are readily fabricated by designing photolithographic masks (Fig. 4a). Polymer networks of various characteristics are available to construct TPNs. For example, we fabricate TPNs in which the hard phases are neutral, cationic, and anionic polymers, and find improvement in elastic limit strain and toughness compared with their corresponding hard gels (Fig. 4b). Furthermore, we fabricate bilayer TPNs by stacking two staggered-patterned scaffolds orthogonally and polymerizing the third network (Fig. 4c). In a peel test of the bilayer TPN gel with a crack at the interface between the layers, we observe cohesive fracture in the bulk gel, but not adhesive fracture at the interface (Supplementary Movie 5). This observation confirms that strong adhesion induced by topological entanglement also forms between the layers. The multilayer TPNs can potentially integrate diverse polymers to mimic the structures and functions of lamellar tissues, such as skins and blood vessels.
In summary, we have developed a class of polymer network morphology, the topoarchitected polymer networks (TPNs), which greatly expand the space of material properties. The TPNs integrate diverse polymers and patterns by sequential polymerization, photolithography, and stacking. The TPNs resolve a longstanding challenge in fabricating architected materials with strong adhesion through topological entanglement. As a demonstration, we fabricate tendon-inspired TPNs that simultaneously achieve high elastic limit strain and high toughness. We further fabricate TPNs of various geometric patterns, material combinations, and multilayer stacks. We have fabricated TPNs using mask photolithography, but TPNs can also be fabricated using other methods, such as stereolithography35. In addition to hydrogels, the TPN principle also applies to other polymer materials, including plastics and elastomers. It is hoped that the TPN technology will be soon developed to enable breakthroughs in material properties.
Cracking the password for WPA2 networks has been roughly the same for many years, but a newer attack requires less interaction and info than previous techniques and has the added advantage of being able to target access points with no one connected. The latest attack against the PMKID uses Hashcat to crack WPA passwords and allows hackers to find networks with weak passwords more easily.
The first downside is the requirement that someone is connected to the network to attack it. The network password might be weak and very easy to break, but without a device connected to kick off briefly, there is no opportunity to capture a handshake, thus no chance to try cracking it.
Rather than relying on intercepting two-way communications between Wi-Fi devices to try cracking the password, an attacker can communicate directly with a vulnerable access point using the new method. On Aug. 4, 2018, a post on the Hashcat forum detailed a new technique leveraging an attack against the RSN IE (Robust Security Network Information Element) of a single EAPOL frame to capture the needed information to attempt a brute-force attack.
Similar to the previous attacks against WPA, the attacker must be in proximity to the network they wish to attack. The objective will be to use a Kali-compatible wireless network adapter to capture the information needed from the network to try brute-forcing the password. Rather than using Aireplay-ng or Aircrack-ng, we'll be using a new wireless attack tool to do this called hcxtools.
Once the PMKID is captured, the next step is to load the hash into Hashcat and attempt to crack the password. This is where hcxtools differs from Besside-ng, in that a conversion step is required to prepare the file for Hashcat. We'll use hcxpcaptool to convert our PCAPNG file into one Hashcat can work with, leaving only the step of selecting a robust list of passwords for your brute-forcing attempts.
It's worth mentioning that not every network is vulnerable to this attack. Because this is an optional field added by some manufacturers, you should not expect universal success with this technique. Whether you can capture the PMKID depends on if the manufacturer of the access point did you the favor of including an element that includes it, and whether you can crack the captured PMKID depends on if the underlying password is contained in your brute-force password list. If either condition is not met, this attack will fail.
In this command, we are starting Hashcat in 16800 mode, which is for attacking WPA-PMKID-PBKDF2 network protocols. Next, we'll specify the name of the file we want to crack, in this case, "galleriaHC.16800." The -a flag tells us which types of attack to use, in this case, a "straight" attack, and then the -w and --kernel-accel=1 flags specifies the highest performance workload profile. If your computer suffers performance issues, you can lower the number in the -w argument.
If you've managed to crack any passwords, you'll see them here. In our test run, none of the PMKIDs we gathered contained passwords in our password list, thus we were unable to crack any of the hashes. This will most likely be your result too against any networks with a strong password but expect to see results here for networks using a weak password.
While the new attack against Wi-Fi passwords makes it easier for hackers to attempt an attack on a target, the same methods that were effective against previous types of WPA cracking remain effective. If your network doesn't even support the robust security element containing the PMKID, this attack has no chance of success. You can audit your own network with hcxtools to see if it is susceptible to this attack.
Because these attacks rely on guessing the password the Wi-Fi network is using, there are two common sources of guesses; The first is users picking default or outrageously bad passwords, such as "12345678" or "password." These will be easily cracked. The second source of password guesses comes from data breaches that reveal millions of real user passwords. Because many users will reuse passwords between different types of accounts, these lists tend to be very effective at cracking Wi-Fi networks.
Chinese lawmakers said that these restrictions are to "safeguard the security of China's geographic information". Song Chaozhi, an official of the State Bureau of Surveying and Mapping, said "foreign organizations who wish to carry out mapping or surveying work within China must make clear that they will not touch upon state secrets or endanger state security". Critics outside of China point out that the laws close critical sectors of the Chinese economy to foreign companies, and assist with cracking down on dissent.
Any way to straighten the Huddart map? I just made one like it and I'd like the map to be level. My next idea was to download PDF with extra space on all sides. convert to JPG, then straighten. Alas, I can't get the "custom" layer to be included on the PDF. Thanks so much for your work. I just found your site yesterday and am still pretty amazed at all that you've designed.
Imagine a task that does not have any prerequisites and is not a blocker for any other tasks. It can be performed at any time regardless of whether other tasks have been completed or not. Thus, it is valid for these nodes to appear in any position in a topologically sorted array. It will depend on the implementation of the algorithm where they eventually end up.