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Sunday, August 23, 2020
Ocean sound: The Oregon Coast rules when it comes to ambient noise
NEWPORT, Ore. - For more than a year, scientists at Oregon State University's Hatfield Marine Science Center deployed a hydrophone in 50 meters of water just off the coast of Newport, Ore., so they could listen to the natural and human-induced sounds emanating from the Pacific Ocean environment.
Their recently published analysis has a simple conclusion: It's really noisy out there.
There are ships, including container shipping traffic, commercial fishers and recreationalists. There are environmental sounds, from waves pounding the beach, to sounds generating by heavy winds. And there are biological sounds, especially the vocalizations of blue whales and fin whales. And not only is Oregon's ocean sound budget varied, it is quite robust.
"We recorded noise generated from local vessels during 66 percent of all hours during the course of a year," said Joe Haxel, an OSU doctoral student who is affiliated with both the Cooperative Institute for Marine Resources Studies (CIMRS) and NOAA's Pacific Marine Environmental Laboratory acoustics program at the Hatfield center. "In fact, there is an acoustic spike during the opening of the commercial crabbing season related to the high number of boats working the shallow coastal waters at the same time.
"But, at times, the biggest contributor to the low-frequency sound budget is from the surf breaking on the beach a few kilometers away," he added. "That's where Oregon trumps most other places. There haven't been a lot of studies targeting surf-generated sound and its effect on ambient noise levels in the coastal ocean, but the few that are out there show a lot less noise than we have. Our waves are off the charts."
The year-long study of noise, which was published in the Journal of the Acoustical Society of America, was supported by the Department of Energy, the Oregon Wave Energy Trust, NOAA and OSU.
The study is about more than scientific curiosity, researchers say. The research was carried out in support of OSU's Northwest National Marine Renewable Energy Center and will play an important role in determining whether testing of wave energy devices off the Oregon coast may have environmental impacts.
Scientists must know what naturally occurring sounds exist, and at what levels, so when new sounds are introduced, there is some context for evaluating their intensity and impact.
Documenting marine noises for an entire year isn't easy, the researchers pointed out. First, the equipment must withstand the rugged Pacific Ocean, so the OSU researchers deployed the hydrophone near the seafloor in about 50 meters of water so violent winter storms wouldn't destroy the instrumentation. They focused on low-frequency sounds, where the majority of noise emitted by wave energy converters is expected to occur.
After combing through an entire year of data, they determined that Oregon's low-frequency noise budget is often dominated by the constant sounds of breaking surf. These weren't necessarily the loudest noises, though.
"The strongest signal we got during the course of the year came from a boat that drove right over our mooring," said Haxel, who is pursuing his doctorate through OSU's College of Earth, Ocean, and Atmospheric Sciences. "The second loudest sound came from the vocalizations of a blue whale, which can be incredibly loud. We were told by colleagues at the Marine Mammal Institute that blue whales have been sighted close to shore in recent years and it was probably within several kilometers of the hydrophone."
Haxel said the OSU researchers also recorded numerous vocalizations of fin whales and humpback whales, but a startling omission was that of gray whales, one of the most common West Coast whales.
"We didn't document a single gray whale sound during the entire year, which was really surprising," Haxel said. "Even during times when gray whales were visually sighted from shore within close proximity of the hydrophone, we never recorded any vocalizations. One theory is that they are trying to keep as quiet as possible so they don't give away their location to orcas, which target their calves."
Another unusual source of noise was the wind. Even at 50 meters below the surface, the hydrophone picked up sound from the wind - but not in the way one might think. It wasn't the howling of the wind that was noticeable, Haxel said, but the ensuing waves, known as "whitecaps" or "wind chop," and the clouds of bubbles that were injected into the water column.
Haxel compared his data on Oregon sounds to a handful of studies in the literature associated with high-energy environmental conditions to see how the region fared. All of the other studies were limited: a Monterey Bay, Calif., survey focused only on surf noises. A study off the Florida coast examined wind-generated sounds. And a study of the Scotia Shelf in Canada looked at wind and surf.
Oregon noise levels were similar to other regions for frequencies above 100 Hz, Haxel said, but rose sharply for frequencies affected by surf-generated noise - generally below 100 Hz.
"The bottom line is that the Pacific Ocean in the Northwest can be a remarkably loud environment and our wave climate in particular is amazing," Haxel said. "That's why wave energy is being targeted for this region in the first place. The study will provide some valuable information as the wave energy industry goes forward.
"We will be able to measure noise levels from the testing, or even the loading and unloading of equipment from the vessels, and compare those measurements with the range of background ambient sound levels already occurring in the area," he added.
"It is a balancing act as some noise from the testing sites may serve as a warning signal for whales and other animals to avoid the area, helping to reduce the risk for collision or entanglement," Haxel said. "But adding too much noise can be harmful, disrupting their communication or navigation."
CREDITS TO SOURCE:
Joe Haxel, 541-867-0282; joe.haxel@oregonstate.edu
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Wednesday, August 19, 2020
Understanding Fastener Notation
Understanding Fastener Notation
Basic Identification
Below is an example of a full fastener description. This notation includes all of the information needed to identify the fastener.
| Fastener description: | Machine screw | Phillips pan | Stainless steel 18-8 | 1/4 - 20 x 2" | |
| Fastener type | Head | Material | Size |
Fastener Type
Fastener Type is the general type of fastener, such as wood screws, hex bolts, machine screws, hex nuts or carriage bolts.
Head
Head types contain up to two parts:
Example:
| Phillips | Pan |
| Drive type | Head style |
Drive Type
Drive type describes the type of tool used to install the fastener. Common examples are phillips, slotted, and square drives.
Some fasteners, such as carriage bolts, do not have a drive and therefore no drive type is specified.
In certain other cases, such as with hex bolts, the head and drive type (hexagonal) is implied by the fastener type.
Head Style
Head style describes the shape of the head. Common examples are pan, flat, truss, and hex.
A few fastener types, including set screws and some anchors, do not have a head and the head property will therefore not be present.
Material
The most common parts of a material description are:
| Example: | Zinc plated | Grade 8 | Steel |
| Plating | Grade | Material |
Plating
Many fasteners, especially steel fasteners, are plated or coated for corrosion resistance or decorative purposes. Common platings include zinc plating, galvanizing, and chrome plating.
Grade
Some materials, such as steel, come in various grades. The grade specifies an exact set of mechanical properties. Examples of common steel grades include grade 2, grade 8, and class 8.8.
Material
This is the basic underlying material. The most common fastener material is steel (including stainless steels), often further specified with a grade (grade 8, etc.). However, many other materials are used including, brass, bronze, and nylon.
This property will always be present even if no grade or plating is specified. Thus, a full material description for a fastener might simply be: Brass.
Other Information
Occasionally the material description will contain other information. Examples include fasteners with painted heads, colored platings such as yellow zinc, or polished finishes.
For more information on materials see our Materials page.
Size
For most fasteners, the size consists of two or three parts. For example:
| Example: | 1/4" | - 20 | x 3" |
| Diameter | Thread count | Length |
Diameter
Diameter is typically measured on the outside of the threads. For US fasteners this is measured in inches (except for small diameters, where diameters are numbered), and for metric fasteners it is measured in millimeters (abbreviated mm or prefixed by M).
For more information on how to measure the diameter of specific fastener types see our Measuring Fastener Diameter page.
Thread Count/Pitch
Only machine threaded fasteners (nuts, and screws/bolts that could take a nut) specify a thread count or thread pitch.
US fasteners specify threads per inch (TPI), commonly called thread count, so 20 would represent 20 threads per inch. Metric fasteners instead specify a thread pitch which is the distance between the threads. Therefore, a 1.5 pitch would have 1.5 millimeters between each thread.
For more information see our Thread Pitch and Thread Count page.
Length
Fastener length is usually measured from where the surface of the material is presumed to be when the fastener is installed, to the end of the fastener. US fasteners are measured in inches, while metric fasteners are measured in millimeters (mm). For more information on how to measure specific fastener types see our Measuring Fastener Length page.
Order and Symbols
Diameter, Thread count/pitch, and Length should always be specified in this order. In addition, slightly different notation is used for US fasteners and Metric fasteners.
In US fasteners, a dash should be used to separate the diameter and thread count (if there is a thread count), while an x is used to seperate them from the length. A double quote (") may or may not be present to indicate the measurement is in inches. A number sign (#) indicates a numeric diameter used with smaller screws. Dropping the number sign for these sizes should be avoided as it can easily result in confusion between US and Metric sizes.
In Metric fasteners, an x is used to seperate each of the parts of the size. Each part (including the thread pitch) is a measurement in millimeters, so each may be followed by the abbreviation mm. Often this is left off from the thread pitch. Sometimes it is also left off of the other parts of the size. This should be avoided as it can lead to confusion with US fastener sizes. To shorten metric sizes many people use a capital M in front of the diameter, and then leave the units off of the other parts of the size. This method results in a shortened size that is still clearly a metric size.
Examples:
US Machine thread US Non-machine thread | Metric machine thread Metric non-machine thread Metric alternative |
Other Properties
Some fasteners have additional special properties. Some examples are special point types (thread cutting, piercing, dog point), integrated washers (neoprene sealing washers, fixed lock washers), special thread locking systems (nylon patch, pre-applied thread locker), and vented screws. These properties are included with the rest of the identification.
Nuts and Washers
Nuts and washers lack many of the properties of other fasteners.
Nuts and washer sizes are the same as the diameter of the fastener they are meant to work with. Thus, a 1/4" washer fits a 1/4" bolt/screw.
Example of a washer description:
| Example: | Flat washer | Stainless steel | 1/4" |
| Type | Material | Size |
Example of a nut description:
| Example: | Hex Nut | Stainless steel | 1/4" - 20 |
| Type | Material | Size |
Types, materials, and sizes are specified as above with the noted exceptions.
Order of Properties
While Bolt Depot uses the order seen at the top of this page, other suppliers may use a different order for the parts that make up the description.
Example:
Instead of
Type Head type Material Size
You might see
Material Type Size Head type
or
Size Material Head type Type
In other cases these various elements may be seperated on a label or ordering sheet. As long as all elements are present the fastener can be easily identified.
Abbreviations
Because fastener descriptions can become quite long, abbreviations are often used.
Examples:
WS = Wood Screw
MS = Machine Screw
Phil = Phillips
S/S = Stainless Steel
G8 = Grade 8 Steel
Thus you may see something like this:
Example: WS Phil. Flat S/S #12 x 2
Despite being greatly shortened this contains the full fastener specification.
Many common abbreviations can be found on our Fastener Abbreviations page.
Note: In addition to abbreviations many people will leave out parts of the fastener description that they expect to either be the 'standard' or that they do not care about. For example, leaving off the thread density because they just want 'standard' (coarse) thread, or not specifying a material grade. It is always better to try to obtain this information prior to making a purchase to avoid errors.
Shop Talk
More Info
Our Printable Fastener Type Chart is a comprehensive illustrated guide to fastener types, drive types, head styles and more.
Our Printable Fastener Type Chart is a comprehensive illustrated guide to fastener types, drive types, head styles and more.Everyone who works with fasteners eventually starts using their own abreviations and terminology. Shouting "Grab me some railing anchors" is a lot easier than "Grab me some three eighths sixteen by four inch stainless steel stud anchors". Often this 'Shop Talk' gets handed down to people who never knew another name for the fastener and sometimes even becomes industry or regional slang.
For those times when you can't identify a fastener by name, we have created a Printable Fastener Type Chart. This type chart, in addition illustrations in our catalog, are designed to help guide you through identifying what you need right down to the specific size.
For help locating a fastener please feel free to contact our customer service department at 866-337-9888
FOR CREDITS PLEASE VISIT: https://www.boltdepot.com
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r/S10plus
exactly make sure the camera lens is super clean sometimes even if you wipe it on your shirt the grease is still there just make a super clean before you try taking pictures if it persists I would recommend replacing it under warranty
Wipe off the lense the clear some sticky moisture on it
At night it normally takes longer for a photo to be taken as camera should be using a wider aperture - try holding your phone still for a bit longer.
That's not blur due to low light (the person would be much more blurred as well). Its lens flare...I'd suggest making sure the camera lens is clean.
Same problem dude
have you tied with night mode?
Wipe your lens
Wipe your damn lens, I never had such light streaks even without night mode.
I have the same problem. I cleaned my lens and its still there. I tried night mode as well and nothing happened.
Did you ever find a solution to this? Hate this camera.