Scientists call this defense mechanism camouflage, and it is one of the most common defense strategies animals use to protect themselves from predators.Ī few animals that have excellent camouflage include: These types of animals are very difficult to see, which means that predators having trouble finding them.įor example, arctic hares are white rabbits who blend in with the snow covering the ground where they live. Some animals evolve color patterns that look almost exactly like their habitats. Some animals use camouflage to help them blend in with their surroundings and avoid detection. Many animals that rely on speed also have excellent vision or hearing, so they can detect predators before they get very close.Ī few species that use speed to escape predators include: Many animals that use speed as a defense live in open habitats, which don’t provide many places to hide from predators. This is a very common defense mechanism that many animals use because it does not require them to evolve complicated things like venom or spines. Some animals try to avoid predators by simply running, flying or swimming away as fast as they can. Some animals have only a few spines, but others are completely covered in them.Ī few animals that use spines to protect themselves include:įor some animals, speed serves as the best protection from predators. Unlike stingers, which can inject venom, spines simply work like a sharp spike that can puncture the skin of a predator. Spines are long, narrow structures that can injure attacking predators. Sharp spines serve as effective protection for many animals. Many poisonous animals have bright colors, which serve as a warning to predators.Ī few animals that use poison to protect themselves from predators include: When a predator touches a poisonous animal or tries to eat one, the poisons usually make the predator very sick. Some animals even keep a layer of poison on their bodies all the time. Instead, poisons are usually allowed to ooze out of an animal’s skin. But unlike venoms, poisons are not injected into an attacker. Poisons are somewhat similar to venoms, as they are also chemicals that are stored in special glands inside an animal’s body. Some animals have toxins on their skin that protect them from predators. Note that some animals, such as rattlesnakes and spiders, also use venom to capture their prey. Most venoms cause the predator to feel a burning pain, and some are even deadly.Ī few animals that use venom to defend themselves include: But, when an animal is threatened by a predator, the animal can inject the venom into the attacker with the help of a stinger, fangs or claws. Venoms are usually stored in a special gland inside the animal’s body. Venoms are special chemicals that some animals use to protect themselves from predators. Some animals inject special toxins called venoms into predators.
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It would go on to become Capcom's best-selling game, with the majority of sales coming from outside of Japan, a first for the series. Monster Hunter: World outsold all of its predecessors within 3 days of its release, when it hit 5 million units. 11 Books 1 Monster Hunter International Larry Correia From 5.19 2 Monster Hunter Vendetta Larry Correia Out of Stock 3 Monster hunter: Alpha Larry Correia From 4. Critics praise it for accommodating western audiences while ultimately still retaining the complex gameplay the series became known for. Monster Hunter: World received critical acclaim globally upon its release. In ’09 there was some serious interest in MHI from a couple of movie studios. All the things from myth, legend, and B-movies are out there, waiting in the shadows. Additionally, Capcom chose to implement features expected by western audiences in modern games namely a fully voiced and comprehensive tutorial and fully voiced cutscenes, a first for the series. Five days after Owen Zastava Pitt pushed his insufferable boss out of a fourteenth story window, he woke up in the hospital with a scarred face, an unbelievable memory, and a job offer. Developing for more powerful consoles also led to the series transitioning to open world gameplay rather than the series' previous layout of discrete areas separated by loading zones. These conditions led to Capcom choosing to develop Monster Hunter: World for modern consoles and PCs, and emphasizing online play rather than ad-hoc multiplayer. Many of you are already familiar with Jason’s work, but if you’re not, he is really good. It takes place in California in the 1970s. While this flourished in Japan where the conditions are ripe for such a feature, it failed to prove significant in the less densely populated west, where console gaming is generally preferred to handheld gaming regardless. This next one is called Monster Hunter Memoirs: Fever, by me and Jason Cordova. While the series began on console, it primarily became a handheld series in Japan, taking advantage of the PSP's ad-hoc multiplayer, allowing local players to drop in and out of game sessions seamlessly. While the games were generally well received critically, they consistently put up poor sales numbers as western audiences repeatedly failed to take to a series which became known its steep learning curve, complexity, and difficulty. Book 6 of 8: Monster Hunters International by Larry Correia Apr 24, 2018. While the Monster Hunter franchise had already been wildly successful in Japan its reception had been more lukewarm in the west. 1-16 of over 4,000 results for 'monster hunter book series'. The player then uses monster parts to craft more powerful weapons and armor, enabling them to hunt for more powerful monsters, leading to more powerful gear. The player takes on the role of a Hunter, and is tasked to hunt various fantastical creatures in one of several distinct open worlds. Monster Hunter: World is a fantasy third-person action RPG developed and published by Capcom for the Xbox One and PlayStation 4 on January 26, 2018, later being released on the PC on August 9, 2018. It doesn’t matter if I’m in light mode or dark mode, it won’t make it through one article until it crashes. With the new IOS 13 on an iPhone XR, TTS crashes constantly now. We're also working on a variety of pagination improvements for future releases and I've filed a request for justified text so we can keep it in consideration. Sorry for any inconvenience, the home bar hiding works on fast pagination as expected but not iBooks due to some technical differences (which I'd be more than happy to outline the specifics of if you want, just let us know at We should be able to introduce support for it for the iBooks pagination display in a future update. Also, the pagination feature to use iBooks like page turns on an iPhone 10 just doesn’t work properly, there’s a huge gap at the bottom of every page, while the top part of the screen and the text is way too close to the upper edge, I just need a simple fix, and maybe that will get fixed along with the lack of full justification, that would be so nice, that I would give it five stars again. Previous: I’ve been a huge fan of Instantpaper for many many years, I love it, but one thing that’s always bugged me, is that there is no full justified text feature to make the margins on either side balance out like you can with Kindle, Nook, iBooks, etc. See below comments with hopes those will get fixed as well as they’re still sane after 7.5.2. Update for 7.5.2 on Jan 23, 2018, which purportedly hides Home indicator when you’re in full screen mode, however, I just tried it, in full screen mode, after closing all apps and restarting, and the home indicator is still there no matter what I try. Thank you for listening, Instapaper folks. Update after developer review: they’re aware of issues and working on fixes and improvements, so that ups it to 3 stars happy to go 4 stars once the spacing issue is fixed with upper and lower borders on iPhone X in iBooks pagination mode, then 5 stars once they dim out the Home indicator. Needs fixes many fixes - used to be one of my apps ever You can manage and cancel your subscriptions by going to your App Store account settings after purchase. Your account will be charged for renewal within 24 hours prior to the end of the current period. The subscription automatically renews unless it is canceled at least 24 hours before the end of the current period. On sign up for Instapaper Premium, payment will be charged to your Apple ID account at the confirmation of purchase. Unlimited use of the speed reading feature to help you get through articles up to 3x faster. Text-to-speech Playlist to seamlessly listen to multiple articles. Full-text search for articles in your account Instapaper also offers an optional Instapaper Premium subscription for $2.99/month or $29.99/year. Sort your list of articles by popularity, date, and article length. Have your Instapaper articles narrated to you with text-to-speech. Find that great quote you want to remember and share? Instapaper makes it easy to highlight and add notes to text in any article. Control every aspect of your reading experience with a variety of font, color themes, and spacing options. Read anywhere! No internet, no problem: access your articles on airplanes, subways, elevators, or away from Internet connections. Strip away all clutter and save the content of web pages into iOS-optimized formatting. Instapaper has been inducted into the iPhone and iPad Hall of Fame, received Macworld Editor's Choice Award, and has also been featured in publications including Wired, TIME, Daring Fireball, and The Verge, among others. Instapaper also enhances the standard reading experience with features like text-to-speech. Instapaper for macOS provides an optimized text view that makes reading Internet content a clean and uncluttered experience. Save with Instapaper, then read later when you’re commuting, in a meeting, or waiting in line.Instapaper is the simplest way to save and store articles for reading: offline, on-the-go, anytime, anywhere, perfectly formatted. Great for long articles and blog posts that you find during the day and would like to read, but don’t have the time when you find them. Critically acclaimed by top blogs, newspapers, and magazines! Save web pages for later offline reading, optimized for readability on your tablet or phone’s screen. A simple tool to save web pages for reading later. I didn’t know much about F for Fake–I swear that I am going to sound like a broken record each week when I say stuff like that–when I turned it on from Hulu. So I guess it makes sense that, when Orson Welles aimed to make a documentary, one ostensibly about an art forger, he threw objective truth out the window with all kinds of glee. But again, accuracy and objective truth are difficult to pin down in any documentary. (I mentioned this on Twitter a couple of years ago: that documentary would need to be extremely long, and it would need to be directed by Ken Burns, or a Ken Burns type.) The PBS documentary wasn’t very good, in part because it offered a lot of surface-level insight to anyone with more than a passing awareness of Walt Disney.Īccuracy and objective truth are difficult to pin down in a documentary about Disney, because our takes on him are influenced by our preexisting opinions on the man. I have no doubt that there is a great documentary to be made of the life and times of Walt Disney, and the legacy he has left behind. What people are asking for when they ask for a documentary that is made objectively is either a) a film made by a series of robots or b) a film that more consistently aligns with their preexisting opinions. How can any documentary actually present objective truth? (Tumblr suggested that I let all of you answer this when I typed that sentence, and NO THANK YOU, TUMBLR.) As soon as the cameras turn on, 100% objectivity is out the window. However, the notion that a documentary should have objective truth is both eminently logical and utterly fallacious. I have, to be clear, not yet watched the show (and I’m not sure if I will, only because the recent spate of true-crime content in popular culture bores me in general). I’ve seen arguments about “objective truth” related to Making a Murderer, too, suggestions that the documentary has failed because it’s too biased. But he does, and it’s just a wild miscalculation.) Part of the problem with the documentary, for me, was that it attempts often to make declarative statements about a man who remains an enigma to so many of us. He won a Pulitzer! He writes about politics! The story of his autistic son using Disney films to communicate is fascinating! I have no idea why he appears almost as frequently as a man who wrote a literal book on Walt Disney’s life in this documentary. (For example, Ron Suskind seems like a nice guy. Some, I would argue, of the talking heads are roughly as qualified to talk about Disney’s life and career as I am. I was, however, about as surprised as those earlier viewers at the amount of talking-head interviews, especially considering how many of those interviews make a lot of leaps of logic. It’s not that the movie is a hit piece (it’s not). Now that I’ve watched the Disney documentary–a novel idea, I know–I disagree with some of those comments, but less than I would have assumed. When I read the comments initially, the tone of them basically read to me as “This documentary isn’t nice enough to Walt Disney,” which suggested that those in favor of this argument don’t get the point of a documentary, especially one that is–I should note–not officially authorized by the Walt Disney Company. (To their credit, the two men I’m referring to are among a very small group who appear in the film who did know or work with the man.) Some Disney fans took the film to task for daring to present him in a darker-than-hoped light. Some of Disney’s old co-workers–who are, to my surprise, interviewed in the documentary itself–harshly criticized the film for its reliance on talking heads who didn’t know Disney. Before I saw the documentary, I read comments on the Disney doc that were, putting it lightly, a bit critical. I won’t go into major detail about my thoughts on the Walt Disney documentary here, but I bring it up because issues of accuracy are hard to ignore within its whole. Debates of accuracy are, conveniently enough, of paramount importance to this week’s Criterion film: Orson Welles’ F for Fake. (If the subtitle, which appears on the DVD cover, but nowhere else that I could see, is confusing, I’ll be clearer: this is the 4-hour documentary that aired on PBS as part of their American Experience program back in September of last year.) And the entire Internet, it feels, is debating the success and accuracy of the new Netflix show Making a Murderer, the latest in a long, long line of true-crime documentaries or documentary-style programs that have taken hold of our attention. For an upcoming bonus episode of my podcast Mousterpiece Cinema, I watched the documentary Walt Disney: He Made Believe. A Twitter poll decided which film I would watch and write about this week, but the timing felt perfect, for a number of reasons. Territories (Puerto Rico & US Virgin Islands) and International or Contact a Local Taxpayer Advocate (LTA) in Hawaii & Pacific US Territories (Guam, American Samoa and the Northern Mariana Islands). To request Taxpayer Advocate assistance, call the Taxpayer Advocate Service toll-free numbers below or refer to Contact a Local Taxpayer Advocate (LTA) in Caribbean U.S. Other items of potential interest: International Taxpayer Advocate: For face-to-face assistance information in Puerto Rico refer to Contact Your Local IRS Office. Virgin Islands may contact the IRS toll free at 80. The IRS has multiple ways that you can track your tax refund. may also contact the IRS by mail at:īusiness taxpayers located outside the U.S. Also, how to check the status of your refund. Individual taxpayers located outside the U.S. Please send your tax forms and correspondence to the applicable address indicated below. Taxpayer service, formerly offered at the foreign posts of duty, is no longer available. Assistors are available Monday through Friday, from 7 a.m. If you are a tax professional or software provider calling about an e-file issue and it is not account related, please contact the e-help office in Austin at 51 (not toll-free). (Eastern time) for all other questionsįax: 68 (for international tax account issues only) There are some pitfalls with the service as it will work with residential and personal post office box addresses but not businesses. The service can be cancelled at any time. The app can be used on both Android and iPhones. The International Call Center is operational Monday through Friday, from: The latest check has been capped at 1,400 Credit: Getty. If you are a taxpayer with specific individual or business account questions you should contact the International Taxpayer Service Call Center by phone or fax. In order to re-enter normal operational model, simply remove and replace power to the device. Reboot the beacon into Direct Firmware Update mode.Ĭontact Radius Networks support for information on the procedure for firmware update or replacement. Press the Action Menu button and select DFU. In order to re-enter configurable mode for a RadBeacon X2, remove the front cover and switch the beacon power switch to OFF and back to ON.Ī beacon set in configurable mode will be configurable for up to 30 minutes or until you lock the device again. In order to re-enter configurable mode for a RadBeacon Tag, remove the front cover and press the configuration push button switch near the coin cell battery. In order to re-enter configurable mode for a RadBeacon USB, remove and restore power to the device. The Lock feature is a security precaution to limit the possibility of third party manipulation of your beacons once they have been installed and configured. Submit a valid PIN to prevent connections from remote Bluetooth 4.0 devices to the beacon configuration service. Press the Action Menu button and select Lock. Submit a valid PIN to reset the settings for your beacon to factory defaults. Reset the device to the original factory settings. Press the Action Menu button and select Reset. Submit a new and existing PIN to update the PIN for your beacon. Press the Action Menu button and select Update PIN. Validate the accuracy of your beacon settings by quickly verifying the ranging behavior of your device in proximity to your configured beacon. Press the Action Menu button and select Range. Update the measured power value with the results of your calibration activity and update your settings. Press the Action Menu button and select Calibrate.Ĭalibrate the measured power value of the beacon settings to ensure optimal proximity events and ranging. Submit a valid PIN to update the settings for this beacon. Press the Action Menu button and select Apply. Select any RadBeacon in the table to view it's detailed settings. Each beacon discovered is displayed with the following summary details Scan for nearby configurable RadBeacons by swiping down on the RadBeacons table. Once discovered, you can display each beacon's operating settings and make modifications to those settings. With the RadBeacon app you can scan for nearby configurable Radius Networks beacons. The RadBeacon app from Radius Networks requires an iOS iPhone, iPad or iPod touch running iOS 7.1 or higher and equipped with Bluetooth 4.0 capabilities. Either the dots dont work or the app doesnt because calibration never completes after 10 readings. The RadBeacon™ app is the configuration utility for RadBeacon proximity beacons from Radius Networks that support Apple's iBeacon™ proximity services as well as other emerging proximity services. Dee apparently owned the manuscript along with a number of other Roger Bacon manuscripts. It is very likely that Emperor Rudolph acquired the manuscript from the English astrologer John Dee (1527-1608). The codex belonged to Emperor Rudolph II of Germany (Holy Roman Emperor, 1576-1612), who purchased it for 600 gold ducats and believed that it was the work of Roger Bacon. Like its contents, the history of ownership of the Voynich manuscript is contested and filled with some gaps. Read a detailed chemical analysis of the Voynich Manuscript (8 p., pdf) History of the Collection Described as a magical or scientific text, nearly every page contains botanical, figurative, and scientific drawings of a provincial but lively character, drawn in ink with vibrant washes in various shades of green, brown, yellow, blue, and red.īased on the subject matter of the drawings, the contents of the manuscript fall into six sections: 1) botanicals containing drawings of 113 unidentified plant species 2) astronomical and astrological drawings including astral charts with radiating circles, suns and moons, Zodiac symbols such as fish (Pisces), a bull (Taurus), and an archer (Sagittarius), nude females emerging from pipes or chimneys, and courtly figures 3) a biological section containing a myriad of drawings of miniature female nudes, most with swelled abdomens, immersed or wading in fluids and oddly interacting with interconnecting tubes and capsules 4) an elaborate array of nine cosmological medallions, many drawn across several folded folios and depicting possible geographical forms 5) pharmaceutical drawings of over 100 different species of medicinal herbs and roots portrayed with jars or vessels in red, blue, or green, and 6) continuous pages of text, possibly recipes, with star-like flowers marking each entry in the margins.įor a complete physical description and foliation, including missing leaves, see the Voynich catalog record. Voynich, who acquired it in 1912-are still being debated as vigorously as its puzzling drawings and undeciphered text. Note: For the reign of Edward I, for the years 1–13 of Edward II, and for the reign of Richard II, modern scholarly editions collated all or some of the known manuscripts for those years, and these manuscripts are listed in the individual records for cases in those years.Written in Central Europe at the end of the 15th or during the 16th century, the origin, language, and date of the Voynich Manuscript-named after the Polish-American antiquarian bookseller, Wilfrid M. Catalogue of English Legal Manuscripts in Cambridge University. Many manuscript Year Books can be found in IDC’s microfiche English Legal Manuscripts and are listed in:īaker, Sir John. Suggestions, corrections, and additions are welcome. It will be completed and supplemented in future months and years. The following list has been compiled in 2003 by Susannah Vale. Some manuscripts will contain variant reports that differ markedly and provide new speeches, names of parties, and other information that have never appeared in print. Some manuscripts will contain reports that have never appeared in print, and so are not indexed in this database. Manuscripts known or believed to contain Year Book reports for a given year or reign, though not necessarily every printed case in that year, are listed in the Table below. One who is researching particular cases for which no modern scholarly edition or translation is found in the Translations/Editions field can consult manuscripts and early printed editions for the relevant regnal year. View Manuscript of the Year Books >View Table of Year Book Abridgements> Where modern editors have given manuscript references, these are included in the Manuscripts field in these database records. Manuscripts may provide variant reports of these printed cases, some longer and some shorter than the case in print. This database indexes and paraphrases Year Books in their most recent printed form, but to settle questions of interpretation and accuracy, manuscripts can often be checked. All of the Year Books were originally reported in manuscript form, and all of them circulated among the legal profession for decades and often centuries in manuscript before they were printed. The other key feature in Cop圜lip is that you can do is set it to ignore copies made from specific apps. This means you don’t have to select it and then paste - just press the right number key and you’re good to go! However, the top ten most recent clippings can be easily pasted by using the hotkey listed next to them for convenience. It looks fairly basic at first – just a collection of links or text clippings stored in the menu bar icon. Cop圜lipĪs lightweight as JumpCut but a little bit cleaner, Cop圜lip has a few special features that make it noteworthy. A free version is available, and the paid version costs $27 at the moment (one-time purchase). Overall, it offers many of the same features as Paste but in a different format, so you should pick based on which one you are most comfortable with. Additionally, you can star/favorite specific snippets, tag them, and sort the list in half a dozen different ways for maximum convenience. It also focuses on adding shortcuts you can use to paste a specific item, which is great if you need to repeat information in multiple places. It stores all your clippings in a scrolling vertical tab so that you can grab one anytime. If you’re looking for something in between JumpCut and Paste, Copy Paste Pro is a good option. Overall, Paste is one of the most convenient and clean clipboard apps available for Mac and will definitely serve you well if you’re willing to spend a little bit. You can organize everything you copy into pinboards by assigning colorful tags, or you can search for something specific using the convenient search bar.įurthermore, you can back everything up to iCloud so that your clipboard history can be accessed on any of your other devices that have Paste installed. But if you want to get something you previously copied, just press Shift + Command + V. You can use the standard Command + V shortcut if you just want to paste your most recent clipping. You’ll see a quick startup screen with a few settings, and then you’re ready to go!Īnytime you copy something, Paste will store it for you. Both versions are completely the same though. You can find it on the Mac App Store (where it’s actually called Paste 2) for $14.99, or you can get it for free with a Setapp subscription (which is what I’m using right now). If you’re looking for something a little fancier that can support more than just text, Paste is a good alternative. Jumpcut is limited to text clippings, and can’t store images for you. To use a particular clipping, just click on it, then press Command + V to paste it where you want to use it. The list shows a sample of whatever you’ve copied, like this: Once you’ve copied and pasted a few things, a list will start to form. Once installed, Jumpcut will appear as a small scissors icon in your menu bar. It looks and functions almost exactly the same, however, unlike JumpCut, you can get Fl圜ut from the Mac App Store. Note: Not comfortable with allowing JumpCut on your Mac? Fl圜ut is a “fork” of JumpCut – this means it’s a version of JumpCut built by a separate team to add additional features by building on the original application. Or you can go to Applications, locate the app, right-click and select Open. Since this is a safe app, you can go to System Preferences > General and pick “Open Anyways” to allow Jumpcut to run. This is completely normal – by default, your Mac tries to protect you from potential viruses by preventing unrecognized programs from running. When you do download it, you will probably see a message saying the app can’t be opened because it is from an unidentified developer. It’s not the fanciest app, but it has been around for a while and will work reliably. JumpCut is an open-source clipboard tool that will allow you to see your full clipboard history as needed. There are a lot of options, so here are a few of our favorites. If you want to copy multiple things, you’ll need to install a clipboard tool to accomplish this. Note: This clipboard feature is pretty limited since you can only see one thing at a time and you can’t recover old items that you’ve copied. To copy something to the clipboard, select it and then press Command + C, and to paste it press Command + V. For example, my clipboard contains a sentence of plain text, but it can also store images or files. When you do this, a small window will pop up and show you what’s being stored and what type of content it is. You can see what’s stored there by opening Finder and then choosing Edit > Show Clipboard. The clipboard is the place where your Mac stores the item you most recently copied. The arena battles could be more fun if players could drift the karts more realistically, perform different quick turns with no given pattern, as opposed to how the already implemented skids limit to. In the end, I believe that the physics used in this game are not bad, but they affect, to a small degree, the overall gameplay by making the game a bit flat with its lack of versatility. However, this game uses karts not cars and the controls and physics of each of them are different so this is a purely subjective observation. Also, while players can perform skids whenever they want with the press of a button, they don’t feel natural. Furthermore, there seems to be no difference on how the karts drive on different terrains and this makes the races feel a bit monotonous. This may have something to do with the physics used and the reduced level of particles in the game. It seem like they’re being driven through air. They feel very light and there is no friction with the road. The karts are responsive to controls, they handle pretty well through corners, but the problem here is that they don’t really feel like karts. This part of the world stays the same from the beginning to the end.Īs far as kart controlling goes, we see that they’re not difficult to control. However, this open world feels quite static since there aren’t any other things or characters to interact with and there is no plot evolution until the end. Players can go to a garage if they want to change the playable character and can drive freely to the unlocked races, choosing the order of playing them at their own will. Immediately after the cutscenes end and players choose their kart, they are spawned in a kind of village that connects all races to one place. Starting with the story mode, I can say that I like the open-world idea adopted for this purpose. So the question is: how’s the gameplay? Well…the gameplay is not bad, but not great either. Overall, the concept is quite broad and it’s apparently designed in a way so players can always stay engaged and have fun.īut, as appealing as the concept may be, it’s no good if the gameplay is not up to the expectations. Another thing worth mentioning is that the game has an add-on feature implemented where players can download custom made tracks and karts, so there’s always something to keep the players going. Some of the races, along with a few new ones can also be played online, but the online multiplayer mode is still a work in progress, by the time I write this review. The multiplayer mode features the same race types, with the exception of Easter egg hunting and they can be played locally in a split-screen environment. Along with the standard races we know from the story mode, there are time trials with no power-ups or slowdowns, races where the goal is to follow the leader and not overpass him, arena competitions where players have to use the power-ups to knock down the other karts, kart soccer, Easter egg hunting and races against one’s self – the so-called ghost races. The singleplayer mode features different race types, so players could always enjoy something new. The three-component (3C) geophone is used for direct measurements of shear waves at the seafloor. Conventional seismic surveys on land use one geophone or a group of geophones per receiver location to detect motion in the vertical direction. Geophones, unlike hydrophones, detect motion rather than pressure. The geophone is a device used in surface seismic acquisition, both onshore and on the seabed offshore, that detects ground velocity produced by seismic waves and transforms the motion into electrical impulses. A typical length of a streamer is about 4-6 km where a single receiver section is typically 75 m long and contains 96 hydrophones which are grouped in arrays of a pre-defined length, mostly 12.5 or 25 m. Hydrophones are combined to form streamers that are towed by seismic vessels or deployed in a borehole. In this way the influence of movements due to currents, wave action and so on will be minimised. The two piezoelectric elements in one hydrophone are connected and polarised so that voltages due to pressure waves (returning signal) add and voltages due to one-directional acceleration will cancel. It measures pressure variations with the aid of piezoelectric material, which generates a voltage upon deformation. The hydrophone is a device designed for use in detecting seismic energy in the form of pressure changes in water during marine seismic acquisition. Hydrophones and geophones serve as receivers for seismic signals. It includes a variety of energy sources based on varying explosive out put parameters to meet geological and climatic conditions. Dynamite can generate usable signal strengths and a bandwidth that covers a wide spectrum of seismic energy. It is customary to drill a hole to load dynamite and fill it with heavy mud before shooting. It provides an impulsive energy that can be converted into ground motion. When dynamite ignites, a shock wave propagates with a speed of 3,000–10,000 m/s. The detonator helps to ignite the explosives. Dynamite a combination of explosive and detonator, is used as a seismic source. The recorded data are then convolved with the original sweep to produce a usable signal. A vibrator source sends a controlled-frequency sweep into the ground. A vibrator is an adjustable mechanical source that delivers vibratory seismic energy into the ground. An air-gun is a device that releases highly compressed air (at typically 2,000–5,000 psi) into the water surrounding the gun. In marine environments seismic energy is normally generated using arrays of air-guns, whereas in land seismic one often uses explosives or vibrators. Different seismic sources are usually used in land and marine acquisitions. |
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