Selecting pipe and piping materials

Steel Pipes
Steel pipes are the most commonly used pipes in water supply systems. They are also used in pipelines for natural gas, and sewerage systems. Although comparatively expensive to other pipes, they hold the advantage of being able to withstand high pressures and are available in more convenient lengths, and can also be welded easily, thereby resulting in lower installation and transportation costs. These types of pipes are highly efficient and can be used in small diameters as needed and are 100% recyclable compared to other materials. The pipes can further be melted down and turned into other usable material in industry. Furthermore, the high strength of these pipes and resistance to damage caused by human errors, tree roots, and extreme weather conditions make these pipes the ideal choice for most water and sewerage supply systems.

The disadvantages of steel pipes include thermal conductivity, which is very poor as there is a difference in heat transfer. These types of pipes are usually bonded with aluminum or copper alloy to increase thermal conductivity and improve heat transfer. Cost is another issue, as these pipes are expensive and this is guided by the misconception of being a one-time purchase. However, steel pipes are difficult to fabricate and lack the malleable qualities that other materials have, therefore repairs and replacements of steel pipes are extra difficult.

Basic material properties

Steel is strong, rigid, and has a low coefficient of thermal expansion. It is also heavy (multiple workers may be needed to transport it) and is subject to corrosion. Sometimes it is called carbon steel or black special steel to differentiate from stainless and galvanized steel. All steel, by definition, contains carbon.

Steel often is used for closed hydronic systems because it is inexpensive, especially when compared with other materials in systems with high pressures, and corrosion is relatively easily controlled in these systems. It also is a good choice for steam and steam-condensate systems because it handles high temperatures and pressures well, and corrosion is normally not an issue in steam pipes. However, corrosion is an issue in steam-condensate pipes, and many engineers specify schedule 80 steel pipe simply because it takes about twice as long to rust through as schedule 40 pipe.

If amines (commonly cyclohexylamine, morpholine, or diethylethanolamine (DEAE) are fed properly to neutralize condensate pipe pH, condensate pipes can last the life of the building. Some building owners do not want these chemicals in steam that may be used for humidification because of health concerns; however, not using these amines might require a change to stainless steel(SS) piping or adding a separate “clean steam” system for humidification and for sterilization of medical instruments.

Rigidity is important because it determines the distance between hangers. Steel pipe is manufactured in 21-ft lengths, and the hangers can be spaced that widely for large-diameter pipe. More flexible materials, however, may require hangers on as close as 4-ft centers or even continuously. Consult ANSI/MSS SP-58: Pipe Hangers and Supports – Materials, Design, Manufacture, Selection, Application, and Installation for details about hangers and hanger spacing.

A low coefficient of thermal expansion minimizes the need for expansion loops and expansion joints. However, the high rigidity of steel means that although it expands less, it exerts very high forces on anchors.

Galvanized steel pipe is steel pipe that is dipped into a pool of zinc (see Figure 1). Galvanizing has two methods of corrosion reduction:

It coats the surface like paint, and under most circumstances it forms a very adherent oxide layer like aluminum and SS.
It provides a sacrificial anode (zinc) to receive corrosion instead of the steel corroding.
Galvanized steel pipe has all the advantages of steel pipe, and is used in insulated and coated piping, plus improved corrosion resistance in most environments, although at a slightly higher cost. Galvanizing works almost perfectly in applications where it is wetted and dried periodically (e.g., road signs and guard rails). It can fail in environments with high sodium (e.g., softened water that started out very hard) because the sodium makes the adherent oxide film detach and react more like steel pipe where the oxide flakes off. If galvanized pipe is being welded, the welder needs to be careful to grind down to the raw steel. Repairing galvanizing on the inside of the pipe is difficult or impossible. If the interior needs a continuous galvanized layer, consider mechanical couplings. (More information is available via the American Galvanizers Association.)

Copper pipe often is used in both hydronic and domestic applications, especially for 2-in. and smaller pipe sizes. However, some contractors propose replacing galvanized steel domestic-water pipe with copper up to 6-in. in size, especially in the Midwest. Copper is an expensive material but has the advantage of weighing less than steel and may require fewer employees to install, depending on weight and union restrictions. Also, copper is generally more noble and corrosion-resistant than steel or galvanized steel pipe fittings.

Stainless steel is widely considered to be resistant to all corrosion. This is true in many circumstances, but not all. Anaerobic and chloride corrosion can affect SS. The most common alloy is 304 SS, which adds 18% chromium and 8% nickel to steel. 304L has reduced carbon content to minimize the tendency for SS to corrode at welds. SS with the L designation is recommended for all SS that will be welded and might have corrosion issues, like fume exhaust and some pipe systems. 316 and 316L add molybdenum to reduce susceptibility to chlorides.

In the past decade, we have seen thinner SS being proposed as an alternative to galvanized seamless steel tube and pipe and larger-diameter copper pipe, primarily for domestic potable-water piping. There is one potential problem with this if done incorrectly (see, “Mixing materials may equal trouble”).

SS requires some oxygen to build an adhering oxide layer, like aluminum car wheels. This is normally not a problem in hydronic heating/cooling systems or domestic-water systems, but a large chilled-water-storage system could have oxygen levels become low enough to have issues with microbially influenced corrosion (known as MIC).

There are many grades of SS. In general, 300 series alloys are the most corrosion-resistant and are nonmagnetic. 400 series are harder, more resistant to abrasion, withstand higher temperatures, and are magnetic. 200 series alloys are used in sinks and applications where less corrosion resistance is acceptable.

Selecting Carbon Black for Paints, Coatings and Inks

Adding carbon black (CB) particles to elastomeric polymers is essential to the successful industrial use of rubber in many applications, and the mechanical reinforcing effect of CB in rubber has been studied for nearly 100 years. Despite these many decades of investigations, the origin of stiffness enhancement of elastomers from incorporating nanometer-scale CB particles is still debated. It is not universally accepted whether the interactions between polymer chains and CB surfaces are purely physical adsorption or whether some polymer–particle chemical bonds are also introduced in the process of mixing and curing the CB-filled rubber compounds. We review key experimental observations of rubber reinforced with CB, including the finding that heat treatment of CB can greatly reduce the filler reinforcement effect in rubber. The details of the particle morphology and surface chemistry are described to give insights into the nature of the CB–elastomer interfaces. This is followed by a discussion of rubber processing effects, the influence of CB on crosslinking, and various chemical modification approaches that have been employed to improve polymer–filler interactions and reinforcement. Finally, we contrast various models that have been proposed for rationalizing the CB reinforcement of elastomers. 

Natural rubber composite has been continuously developed due to its advantages such as a good combination of strength and damping property. Most of carbon black (CB)/Natural Rubber (NR) composite were used as material in tyre industry. The addition of CB in natural rubber is very important to enhance the strength of natural rubber. The particle loading and different structure of CB can affect the composite strength. The effects of CB particle loading of 20, 25 and 30 wt% and the effects of CB structures of N220, N330, N550 and N660 series on tensile property of composite were investigated. The result shows that the tensile strength and elastic modulus of natural rubber/CB composite was higher than pure natural rubber. From SEM observation the agglomeration of CB aggregate increases with particle loading. It leads to decrease of tensile strength of composite as more particle was added. High structure of CB particle i.e. N220 resulted in highest tensile stress. In fact, composite reinforced by N660 CB particle shown a comparable tensile strength and elastic modulus with N220 CB particle. SEM observation shows that agglomeration of CB aggregates of N330 and N550 results in lower stress of associate NR/CB composite.

Carbon black is a highly engineered form of carbon widely used in paints as paint carbon black, coatings and inks to achieve a spectrum ranging from gray to deep black. Over the time, the properties of carbon black pigment have been modified to achieve required properties in the final product, such as increased tinting strength, improved the level of jetness or blue undertone and conductivity.

Explore the different carbon black production processes and the properties to consider while selecting the right carbon black for your formulations.

Properties and End-uses of Carbon Black
Carbon black is used in many products and articles we use and see around us on a daily basis, such as: rubbers, plastics, coatings, tires, ink carbon clack.

Thus, the requirements for the carbon black are different for each application and influence the specific properties in the final application.

For the coating carbon blacks market, there is a wide range of carbon black grades available. This can make it difficult to choose the most suitable carbon black for your final application. For example, when aiming for automotive paint with a blue undertone, the carbon black of choice will have a high jetness. However, normally these types of carbon black grades are the most difficult to disperse correctly into the desired particle size.

The carbon black producers are addressing these issues by developing specialty carbon black grades that have been surface-modified and/or are pre-treated to overcome these difficulties.

How Carbon Black is Produced?
The properties of the carbon black are influenced by the method of preparation. The different processes used for channel carbon black production are discussed below.

Furnace Black Process: It is the most common method which uses (aromatic) hydrocarbon oil as the raw material. Due to its high yield and possibility to control the particle size and structure, it is most suitable for mass production of carbon black.

In the reactor the conditions (e.g. pressure and temperature) are controlled to provide a number of reactions. The most important reactions include: particle nucleation, particle growth, aggregate formation. Water injection rapidly reduces the temperature and ends the reaction. The primary particle size and structure of the carbon black is controlled by tuning the conditions in the reactor and the time allowed before the reaction is quenched.

Thermal Black Process: It is the most common method used for carbon black production after the furnace black process. It is a discontinuous or cyclical process.

This process uses natural methane gas as raw material. When the natural gas is injected into the furnace at an inert atmosphere, the gas decomposes into carbon black and hydrogen. The carbon black produced using this method has the largest particle size and the lowest degree of aggregates or structure. Due to the nature of the raw material, this carbon black is the purest form available on the industrial scale.

Channel Process: This process uses partially combusted fuel which is brought into contact with H-shaped channel steel. It is not the most used method anymore because of its:

The benefit of this process is that it provides carbon black with a lot of functional groups.

Acetylene Black Process: This process uses acetylene gas as raw material. It produces mainly high structure and higher crystallinity, making this type of carbon black suitable for electric conductive applications.

Lampblack Process: It is the oldest industrial process for making carbon black. It uses mineral/vegetable oils as its raw material.

Recovered Carbon Black from End-of-life Tires

Recovered carbon black or ®CB is a fast-expanding market. Recovered high purity carbon black is obtained through the pyrolysis process of end-of-life tires. The importance of companies in the production and use of recovered carbon black is three-fold:

The growing global problems arising with end-of-life tires (ELT)
Companies shifting strategy to fulfill the targets ensuring a green economy
Price changes of regular carbon black due to fluctuations in oil pricing

Depending on the composition, the content of carbon black in tires can be up to 30%. Next to carbon black, the tires consists:

Rubber processing additives
Fillers such as silica

The amount of silica depends on the type of tire, for example winter or summer tire, racing tire, or tire for agricultural vehicles, and will not be separated from the carbon black during the pyrolysis process, which will result in higher ash content.

In a typical car tire, up to 15 different types of conductive carbon blacks can be used, each attributing to the different properties required. This blend of environmental carbon blacks will then also be the make-up of the final ®CB composition. Besides tires, other sources that can be used are rubber conveyor belts or other technical rubber products.

The main differences in the properties of recovered carbon black are:

The ash content is higher for ®CB caused by the fillers being used in tire production.
A blend of rubber carbon black properties as a result of the carbon black used in the tire.
Residual hydrocarbons on the carbon black surface, depending on the quality of the pyrolysis process.

To understand how the properties of ®CB influence the final applications and to know which plastic carbon black is used in which category, we need to understand the fundamental differences between the available carbon blacks.

Selecting elements of sublists or reshaping a list of lists

I have this list

{{{0.05792, 0.31744}, 0., 0., 0., 0.,    0.}, {0., {0.28832, 0.49024}, {0.17173, 0.386393}, 0., 0.,    0.}, {0., {0.17173, 0.386393}, {0.104, 0.352}, 0., 0., 0.}, {0., 0.,    0., {0.30752, 0.38464}, {0.322232, 0.260264}, {0.214663,     0.107331}}, {0., 0.,    0., {0.322232, 0.260264}, {0.392, 0.496}, {0.277128,     0.415692}}, {0., 0.,    0., {0.214663, 0.107331}, {0.277128, 0.415692}, {0.2, 0.4}}} 

or in the matrix form: enter image description here

I would like to convert this list to a list of two matrices, each of the same size as the input matrix, i.e. 6 by 6, where the non-zero entries for the first matrix are given by the first element of the lists in the input matrix and the same for the second matrix.

If it helps I can also create a matrix where the zeros are replaced by a list of two zeros to match the dimension.

How to get a value-only flat array from $wpdb->get_results when selecting a single column, without foreach()?

My query is:

$  var = $  wpdb->get_results("SELECT field FROM {$  wpdb->prefix}table", ARRAY_A); var_dump($  var); 

it returns someting like array(2) { [0]=> array(1) { ["field"]=> string(5) "test1" } [1]=> array(1) { ["field"]=> string(t) "test2" }. I.e. each item is a row with a single name-value pair.

What I want is array(2) { [0]=> string(5) "test1" [1]=> string(5) "test2" }

Currently I achieve it like this:

$  var = $  wpdb->get_results("SELECT field FROM {$  wpdb->prefix}table"); foreach($  var as $  v_key => $  v_val) $  var[$  v_key] = $  v_val['field']; var_dump($  var); 

Is there a shorter way to do this?

Selecting a record based off conditions CLOB

I have a table with a column storing JSON data as a CLOB. The JSON has a ‘miscData’ field that is made up of an array of JSON objects. Each object has 2 keys which are always the same, but the values are different.

. . . "otherKeys" : "otherValues", "miscData": [         {             "miscType": "date",             "miscText": "2020-07-09T10:01:10.450Z"         },         {             "miscType": "Comment",             "miscText": "Comment body"         },         {             "miscType": "CORRECT_TYPE",             "miscText": "SELECT_ME"         }     ], "confirmationNumber" : "123456789qwerty", . . . 

I need to

SELECT      CLOB_COL.miscData.miscText  WHERE     CLOB_COL.miscData.miscType = 'CORRECT_TYPE'  AND      CLOB_COL.confirmationNumber = 'xxxx'; 

But I am having trouble since miscData is an array of objects which all contain miscType and miscData keys and I can’t guarantee the array will be the same size, or in the same order.

Unable to create dynamic button link after selecting product

This is my website- I used WPForms to create form across all the websites. After submitting information the user will redirect to this page- When the user selects a specific product he will redirect to the Amazon review page. The review link will be different for every product. My question is how can I add a dynamic button link for each product? I’m using the Elementor page builder to create this button. Thanks guys for your help!

Why is my view selecting hundreds of duplicates?

This view selects 696 entries. The CSV file has 48 entries.

CREATE OR REPLACE VIEW insert_3_char_abts AS SELECT     ext.construct_id,     n_term,     enz_name,     c_term,     cpp,     mutations,     ext.g_batch,     ext.p_batch,     emptycol,          c_batch,     abts5_mean,     abts5_SD,     abts5_n,     abts5_method,     abts5_study_id,     abts7_mean,     abts7_SD,     abts7_n,     abts7_method,     abts7_study_id,     pur.pk_purified_enz_id FROM EXTERNAL ((        construct_id NUMBER(10),       n_term VARCHAR2 (50),       enz_name VARCHAR2 (50),       c_term VARCHAR2 (50),       cpp VARCHAR2 (50),       mutations VARCHAR2 (50),       g_batch VARCHAR2 (50),       p_batch VARCHAR2 (50),       emptycol VARCHAR2(50),        c_batch VARCHAR2 (50),       abts5_mean NUMBER (5, 2),       abts5_SD NUMBER (5, 2),       abts5_n NUMBER (3),       abts5_method VARCHAR2 (50),       abts5_study_id VARCHAR2 (8),       abts7_mean NUMBER (5, 2),       abts7_SD NUMBER (5, 2),       abts7_n NUMBER (3),       abts7_method VARCHAR2 (50),       abts7_study_id VARCHAR2 (8))            TYPE ORACLE_LOADER     DEFAULT DIRECTORY data_to_input     ACCESS PARAMETERS (         RECORDS DELIMITED BY NEWLINE          SKIP 1         BADFILE bad_files:'badflie_view_before_insert_char_abts.bad'         FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'         MISSING FIELD VALUES ARE NULL          )      LOCATION ('CHAR_ABTS.CSV')     REJECT LIMIT UNLIMITED) ext  INNER JOIN purified_enz pur ON ext.p_batch = pur.p_batch INNER JOIN produced pr  ON pr.pk_produced_id = pur.fk_produced_id; ; 

If I finish this statement with

AND pr.fk_construct_id = ext.construct_id; 

It selects 46 out of 48 records, which is better, but not great.

Selecting n elements from array in sublinear time using indices?

Are GPUs or CPUs capable of selecting n elements from an array in sublinear time using indices? If so, what would be some good alternatives to achieve this?

Lets say I have an array A = {1, 5, 6, 3, 6, 2} and indices I = {2, 5, 2, 4, 1, 0}. The resulting array should be: B = {6, 2, 6, 6, 5, 1}. The time complexity for this should be sublinear with respect to the length of I.

header > img not selecting working

On my website, I can't select a particular image (in order to style it to width: 180px). Note that it is currently the right size because I was forced to use inline style, but I want it be controlled with CSS.

It is an img inside of a header parent, but:

header > img

doesn't select it. Neither does img#logo (an id I put on it).

Weirdly, this works perfectly both when directly opening the site from my C: drive and while opening it using my ampps local host, also on my…

header > img not selecting working