What is DV/DRV hydraulic adjustable flow control valve?
DV/ DRV Hydraulic adjustable flow control valve controls the flow of fluid by adjusting the hand wheel to achieve different size of throttling orifice, it is like a needle pin screwed in the valve. DV/ DRV hydraulic adjustable flow control valve are the throttle valve and throttle check valves.
When should I use DV/DVF series valves?
Use DV/DVF series valves in locations where the use of a separate pressure vacuum breaker (PVB) or a double-check valve is required by city codes to protect against back flow. Check your local city codes to determine what type of valves are required.
Why rain bird DV/DVF valves?
The Rain Bird DV/DVF valve is the premium valve product chosen by more professionals than any other valve on the market. Its long history of reliable performance makes it the natural choice for your landscape.
What is valve flow coefficient (Cv)?
Valve Flow Coefficient (Cv) is a valve’s capacity for a liquid or gas to flow through it. It is technically defined as “the volume of water at 60°F (in US gallons) that will flow through a valve per minute with a pressure drop of 1 psi across the valve.”. In simpler terms, the larger the opening in a valve, the larger the Cv.
What is ductus venosus flow?
The ductus venosus is a shunt that allows oxygenated blood in the umbilical vein to bypass the liver and is essential for normal fetal circulation. [1] Blood becomes oxygenated in the placenta and travels to the right atrium via umbilical veins through the ductus venosus, then to the inferior vena cava.
What is DV in NT scan?
Background: The ductus venosus (DV) is an intrahepatic end-part of the umbilical vein. Inappropriate first trimester DV Doppler blood flow patterns correspond to a higher risk of chromosomal abnormalities.
What is the importance of ductus venosus?
The ductus venosus allows oxygenated and nutrient-rich venous blood to flow from the placenta to the myocardium and brain. Increased impedance to flow in the fetal ductus venosus is associated with fetal aneuploidies, cardiac defects and other adverse pregnancy outcomes.
What does ductus venosus a wave negative mean?
The presence of absent or reversed flow in the ductus venosus during atrial systole (absent/reversed a-wave) is associated with poor perinatal outcomes and implies failure of fetal compensatory mechanisms to preferentially supply vital organs with well oxygenated blood (Baschat et al., 2003).
What is the normal range of ductus venosus?
Ductus venosus S wave and A wave velocities increased linearly from a mean of 38.30 at the first trimester to 61.68 at the third trimester and from a mean of 11.38 at the first trimester to 30.71 at the third trimester respectively.
How do you calculate ductus venosus PI?
DV-PIV was calculated using the formula of Kessler et al. 14: PI = (Vs − Va)/Vmax, where Vs = peak velocity during ventricular systole, Va = minimum velocity during atrial contraction and Vmax = time averaged maximum velocity.
What happens if ductus venosus does not close?
After birth, the ductus venosus closes due to changes in intracardiac pressures and a decrease in endogenous prostaglandins. Failure of the ductus venosus to close may result in galactosemia, hypoxemia, encephalopathy with hyperammonia, and hepatic dysfunction.
What keeps the ductus venosus open?
They showed that, as for the ductus arteriosus, prostaglandin acts to keep the ductus venosus open, and cytochrome P450 haemoprotein and thromboxane A2 promote its closure.
What does the ductus venosus become in adults?
“The umbilical vein and the ductus venosus become completely obliterated between the second and fifth days after birth, and ultimately dwindle to fibrous cords, the former becoming the round ligament of the liver, and the latter the fibrous cord, which in the adult may be traced along the fissure of the ductus venoms” ...
What is DV HR in ultrasound?
What is Ductus Venosus (DV) Screening. In your un-born baby, the ductus venosus provides approximately half of the blood flow of the umbilical vein directly to the inferior vena cava. This allows oxygenated blood from the placenta to bypass the liver.
How many mm is normal nuchal translucency?
A baby with an NT of 1.3mm is within the normal range. The baby with an NT of 2.9mm is also within the limit of normal range. Anything less than 3.5mm is considered within the normal range, meaning the likelihood of Down syndrome is low .
What is the normal NT measurement at 13 weeks?
During the routine first trimester screening at 13 weeks of gestation, NT was measured at 3 mm. The normal range of NT for this age is 1.6-2.4 mm.
How do I read NT scan report?
For example, if the result of your scan shows you have a one in 1,000 chance, it means that for every 1,000 babies with your level of likelihood, one will have Down's syndrome. The higher the second number, the smaller the chance. A chance of one in 150 (or a number lower than 150) is considered high.
Can we know baby gender in NT scan?
There were no relations between fetal gender and FHR and also NT. Conclusions: Gender can be detected with great accuracy in gestations between 11 to 13 weeks and 6 days by using AGD. CRL and gestational week (GW) were determined as nonsignificant predictors of fetal gender by AGD measurement.
What is normal range for nuchal translucency at 12 weeks?
First trimester measurement of NT at 12 weeks of gestation was 3.2 mm during the routine first trimester screening. The normal range of NT for this age is 1.1-3 mm.
What is a good NT measurement?
A baby with an NT of 1.3mm is within the normal range. The baby with an NT of 2.9mm is also within the limit of normal range. Anything less than 3.5mm is considered within the normal range, meaning the likelihood of Down syndrome is low .
What is DV plan?
The DV plan documents the timing and requirements for the DV testing including what tests will be performed, the order they will be performed in. The plan includes the following:
What is the analysis step of DV?
The analysis step of DV verifies that the design meets the safety and project requirements along with determining what additional test may be required. As can be seen in ISO26262 tables above this includes:
What is the first step in DV?
Once the design and safety requirements are fully determined the first step of DV is developing the design verification plan (DVP) f rom the design and safety requirements. The DVP includes acceptance criteria for the tests to show that the design meets the requirements. This acceptance criteria is usually included in the test specifications called out by a customer or industry standard.
What is DFMEA in Dana?
As the Table 1 above shows, design failure mode effects analysis (DFMEA) is an inductive method used to analyze what the effects of a failure would be and what could cause those failures. DFMEA drives how to determine what components and subsystems require special attention in testing to determine the system will be robust enough to meet the requirements. The DFMEA process is used in most Dana projects.
Why do designers need to do DV?
These tests stress the design to reveal deficiencies that cause the design to not meet requirements or cause premature failures. Discovery during DV allows these deficiencies to be addressed before the design goes to production.
What is FTA analysis?
FTA – Fault tree analysis is a deductive method to determine what faults could happened and what lower level events could lead to those faults.
What is domestic violence?
Domestic violence is the willful intimidation, physical assault, battery, sexual assault, and or other abusive behavior as part of a systematic pattern of power and control perpetrated by one intimate partner against another. It includes physical violence, sexual violence, psychological violence, and emotional abuse. The frequency and severity of domestic violence can vary dramatically; however, the one constant component of domestic violence is one partner’s consistent efforts to maintain power and control over the other.
What is the most common form of domestic violence?
Physical and sexual assaults, or threats to commit them , are the most apparent forms of domestic violence and are usually the actions that make others aware of the problem. However, regular use of other abusive behaviors by the abuser, when reinforced by one or more acts of physical violence, makes up a larger scope of abuse. Although physical assaults may occur only occasionally, they instill fear of future violent attacks and allow the abuser to control the victim’s life and circumstances.
How does domestic violence affect people?
Domestic violence is an epidemic affecting individuals in every community, regardless of age, economic status, sexual orientation, gender, race, religion, or nationality. It is often accompanied by emotionally abusive and controlling behavior that is only a fraction of a systematic pattern of dominance and control. Domestic violence can result in physical injury, psychological trauma, and in severe cases, even death. The devastating physical, emotional, and psychological consequences of domestic violence can cross generations and last a lifetime.
Do domestic violence victims have self confidence?
Victims of domestic violence do not bring violence upon themselves, they do not always lack self-confidence, nor are they just as abusive as the abuser. Violence in relationships occurs when one person feels entitled to power and control over their partner and chooses to use abuse to gain and maintain that control. In relationships where domestic violence exists, violence is not equal, even if the victim fights back or instigates violence in an effort to diffuse a situation. There is always one person who is the primary, constant source of power, control, and abuse in the relationship.
Can anyone be a victim of domestic violence?
Anyone can be a victim of domestic violence. There is NO “typical victim.” Victims of domestic violence come from all walks of life, varying age groups, backgrounds, communities, cultures, ethnicities, religions, education levels, economic levels and lifestyles.
Is domestic violence physical or emotional?
It is important to note that domestic violence does not always manifest as physical abuse. Emotional and psychological abuse can often be just as extreme as physical violence. Lack of physical violence does not mean the abuser is any less dangerous to the victim, nor does it mean the victim is any less trapped by the abuse.
What is derivative DV/DY?
The derivative dv/dy is called the velocity gradient.
What is fluid viscosity?
Fluid Viscosity, sometimes referred to as dynamic viscosity or absolute viscosity, is the fluid's resistance to flow, which is caused by a shearing stress within a flowing fluid and between a flowing fluid and its container.
How to measure viscosity?
Viscosity can be measured by timing the flow of a known volume of fluid from a viscosity measuring cup. The timings can be used in a formula to estimate the kinematic viscosity value of the fluid in Centistokes (cSt).
How to determine if a flow is laminar or turbulent?
To determine whether the flow is laminar or turbulent requires that you calculate the Reynold's number of the flowing fluid. Laminar flow will occur where the Reynold's number is less than 2300.
How to determine kinematic viscosity?
The kinematic viscosity can also be determined by dividing the dynamic viscosity by the fluid density.
What is Valve Flow Coefficient (Cv)?
Valve Flow Coefficient (Cv) is a valve’s capacity for a liquid or gas to flow through it. It is technically defined as “the volume of water at 60°F (in US gallons) that will flow through a valve per minute with a pressure drop of 1 psi across the valve.”
What happens to the CV of a valve when it is fully open?
In simpler terms, the larger the opening in a valve, the larger the Cv. As a valve is opening, the Cv increases until the valve is fully open, where it reaches its highest possible Cv, or 100% open Cv.
What is the maximum CV for a Kimray back pressure regulator?
As the stem opens, the CV increases. The maximum Cv for the 2-inch valve is 47; the maximum for the 3-inch valve is 117.
