Looking for "PVC cijevi"?
Articles about PVC cijevi
What articles can you find on Google about PVC cijevi:
Plastics are also called synthetic resins and are broadly classified into two categories: thermosetting resins and thermoplastic resins.
The thermosetting resins include phenolic resin and melamine resin, which are thermally hardened and never become soft again. Thermoplastic resins include PVC, polyethylene (PE), polystyrene (PS) and polypropylene (PP), which can be re-softened by heating.
Usually, thermoplastics are supplied in the form of pelletised material (compounds) with additives (antioxidants, etc.) already blended in it. However, PVC resin is often supplied in powder form and long term storage is possible since the material is resistant to oxidation and degradation. Various additives and pigments are added to PVC during the processing stage, and the blend is then converted into PVC products.
PVC is sometimes known as ‘Vinyl’ in Europe and predominantly so in North America. In Europe, ‘Vinyl’ usually refers to certain specific flexible applications, such as flooring, decorative sheets and artificial leather.
PVC is a thermoplastic made of 57% chlorine (derived from industrial grade salt) and 43% carbon (derived predominantly from oil / gas via ethylene). It is less dependent than other polymers on crude oil or natural gas, which are nonrenewable, and hence can be regarded as a natural resource saving plastic, in contrast to plastics such as PE, PP, PET and PS, which are totally dependent on oil or gas. This chlorine gives to PVC excellent fire resistance.
Premature ventricular contractions (PVCs) are the most common cause of irregular heart rhythms.
The heartbeat is created by an electrical signal that originates in an area of specialized cells in the heart’s upper right chamber, the right atrium. The electrical signal moves down through the heart to the atrioventricular (AV) node, a cluster of specialized cells in the center of the heart. From the AV node the signal passes along special fibers embedded in the heart walls to the ventricles, the lower chambers. When the electrical current arrives in the ventricles, it causes them to contract and pump oxygen-rich blood out to the body.What are premature ventricular contractions?
A premature ventricular contraction (PVC) is a too-early heartbeat that originates in the ventricles and disrupts the heart’s normal rhythm. The pattern is a normal beat, an extra beat (the PVC), a slight pause, then a stronger-than-normal beat. The heart fills with more blood during the pause following the PVC, giving the next beat extra force. This pattern may occur randomly or at definite intervals.Who is at risk for PVCs?
Almost everyone has PVCs at some time, from childhood through adulthood. In a study of healthy members of the military, the incidence of PVCs was 0.5% among those under the age of 20 and 2.2% in those over the age of 50. This study shows the rise in PVCs – as in all types of abnormal heart rhythms – that occurs with age. PVCs occur more commonly in older people and in individuals with underlying heart disease, including a history of heart attack. People with a family history of cardiac arrhythmias (abnormal heart rhythm) also have a higher risk for PVCs.What causes PVCs?
Healthy people of any age can experience PVCs. In most cases of occasional PVCs the underlying cause cannot be identified.
PVCs that occur frequently or for longer periods of time are more likely to be related to heart disease, an injury to the heart or other, non-cardiac conditions such as a chemical imbalance in the body. Certain medications, alcohol, illegal drugs and high levels of adrenaline due to stress, exercise or caffeine also can cause PVCs.
Watch video about PVC cijevi
What can you find on YouTube:Kako napraviti vazdusnu pucaljku od PVC cijevi