1, Corrosion-resistant. Polyethylene is an inert material, except for a few strong oxidant, can withstand a variety of chemical media erosion.2, Without leak. Polyethylene welded steel pipe mainly welded connection (hot melt connection or fused connection), ensure that the interface material, structure and management body’s own identity in essence, to achieve the integration of joint and pipe. Test confirmed that the tensile strength and burst strength of the interface was higher than the pipe body, can effectively resist the tensile stress in the pressure generated hoop stress and axial direction.3, High toughness. Polyethylene coating steel pipe is a high toughness of the pipe, which is generally more than elongation at break of 500%, based on the pipe’s ability to adapt to uneven settlement is very strong. It is an excellent seismic performance of the pipeline.4, With excellent flexibility. Polyethylene flexible polyethylene tube can be coiled, and a longer length of the supply does not need all kinds of connecting pipe opponent, and it is easy to process in accordance with the requirements of the construction changes, but also changes in the pre-construction pipe shape, old tube inserted to restore the original size and dimensions.5, With a good ability to resist scratches. Studies have shown, PE80 grade polyethylene pipe has better resistance to SCG ability and scratch-resistant capability. PE100 polyethylene pipe materials are having a better ability to resist scratches.6, Good resistance to rapid crack pass. Polyethylene has excellent ability to transfer resistance to rapid crack. For the lower the temperature, the greater the diameter and wall thickness, the higher working pressure, rapid crack the plastic pipe the greater the risk characteristics. The polyethylene pipe, especially PE100 pipe more suitable for big diameter mild steel pipe. Currently, the standard polyethylene gas pipe foreign (IS04437-1997 and EN1555) has resistance to rapid crack growth (RCP) being included in the standard.7, Long service life. ≤60 under the conditions can be used for more than 50 years.
Identification the Fake of Thick Walled Steel Pipes
1. Shoddy thick-walled steel pipe prone to folding.2. Bad thick-walled steel pipe surface prone to scarring.3. Pseudo-inferior material surface is easy to crack.4. Fake thick-walled mild steel pipe easy to scratch.5. Shoddy thick-walled steel pipe without metallic luster, pale red or similar pig iron color.6. Counterfeit thick-walled steel tube of fine and low cross-ribs, often appear dissatisfied with the phenomenon.7. Fake thick-walled steel pipe cross-section was oval.8. Fake thick-walled steel pipe material containing impurities, steel density is too small.9. Forged thick-walled steel pipe diameter size fluctuations.10. Quality control of the trademark and printing are more standardized.11. Three large diameter pipe diameter 16 or more, the spacing between the two trademarks are above the IM.12. Shoddy steel The longitudinal reinforcement of rebar is often wavy.13. Counterfeit thick-walled structural steel pipe manufacturers do not drive, so packaged more loose. The sides are oval.
Blocks Important Enzymes
Antibiotics were once a “secret weapon” for humans to fight many diseases. In the late 19th and early 20th centuries, due to the discovery of a series of antibiotics, human lifespan was greatly improved. But it was less than a century since it was invented. Because of the increasing resistance of bacteria to antibiotics, antibiotics have gradually stepped down from the “sacred altar” and even become a major challenge in the field of medical and health care in the future.
The effectiveness of antibiotics is generally declining. The reason is that antibiotic-resistant bacteria are spreading rapidly, and resistant bacteria are not killed by certain antibiotics, and then they are no longer restricted and their resistance is even transmitted. Because of the resistance to antibiotics, some common pathogens are becoming so-called “super bacteria”. Once antibiotics fail, our lives are fraught with danger-minor abrasions can lead to death, and minor ear infections can cause deafness.
The problem of antibiotic resistance has increasingly become a problem that plagues countries around the world. The World Health Organization has published a report saying that by 2050, bacterial resistance to antibiotics will kill 10 million people every year, equivalent to one person losing their life every 3 seconds, and the harm will exceed cancer. At the same time, the most worrying thing is that this harmfulness is increasing year by year. For example, the treatment of E. coli is usually effective with ordinary antibiotics, but in recent years, many countries have reported that some patients even use the most powerful antibiotics to no avail. At present, approximately 25,000 people are killed each year in Europe, causing 1.5 billion euros in annual medical costs and economic losses in the EU. Globally, about 700,000 people die from various drug-resistant infections every year, and 230,000 Newborns died as a result.
Antibiotic resistance has become one of the world’s difficult problems. But recently, good news came from the Technical University of Munich, Germany. A team of chemists at the school proposed a new method: they have identified important enzymes in the metabolism of S. aureus. Breaking these enzymes can starve the pathogen.
“Many bacteria have developed resistance to broad-spectrum drugs, and an important goal of this research is to find new points of attack.” Professor Stephan Sieber of the Technical University of Munich, together with his doctoral student Annabelle Hoegl and others, developed an isolation And the method of metabolizing enzymes, which can control the metabolic process, and if they are blocked, they can “starve” the pathogen more or less.
Their latest study tested S. aureus. This bacterium is made up of thousands of proteins and is ubiquitous in the world, and some S. aureus species are resistant to antibiotics. Stephan Sieber said that being able to isolate needles with characteristic properties in a haystack, identifying them, and investigating their functionality is a real challenge.
In this experiment, researchers used vitamin B6 to accelerate intracellular chemical reactions. A key component of vitamin B6 is pyridoxal phosphate (PLP). Without pyridoxal phosphate-dependent enzymes, the bacterial metabolism would Interruptions can cause bacteria to starve to death.
The team then used chemically modified pyridoxal phosphate to detect PLP-dependent enzymes, and the labeled molecules were placed in the nutrient solution of S. aureus. Because the nutrient solution does not contain natural pyridoxal phosphate, PLP-dependent enzymes will bind to these labeled molecules, and the researchers will then use an ultrasonic device to break down these bacteria and pick out the enzymes that carry the label. The basic principle of molecular selection is also called “protein profiling”. This is not a new technology, but scientists at the Technical University of Munich have used this method for the first time to investigate and analyze PLP-dependent enzymes.
Stephan Sieber said: “We can confirm that this method is very effective and feasible. Many important enzyme substances in staphylococci rely on pyridoxal phosphate. We selected and isolated 73% of the enzymes and identified them by mass spectrometry.
In addition, the researchers discovered previously unknown PLP-dependent enzymes and deciphered their function. Stephan Sieber sees the search for new antibiotic targets as a treasure trove.
This discovery can be used to develop new antibacterial active drugs. In the next step, researchers hope to study the functionality of enzymes in more detail and determine how to block the metabolism of bacteria in a targeted manner without harming the health of human cells.