Location Of Blockages Research Articles

Research on Method for Detecting Pipeline Blockages Based on Fluid Oscillation Theory

To address the problem of pipeline blockage detection, a mathematical model of pipeline blockage detection is established based on fluid oscillation theory. This paper proposes a governing equation of the water hammer of fluid motion in a pipeline with a blockage point, and The Dirac function is introduced for dimensionlessness and linearization. The amplitude of the harmonic of each component in different periods is expressed by a Fourier series. The blocking position can be determined by the ratio of the two-component harmonics, and the blocking magnitude can be determined by the blocking attenuation parameters of each component’s harmonics. The numerical simulation and experimental results show that the application of fluid oscillation theory to detect the location and magnitude of pipeline blockages is effective, and the accuracy of the detection method is verified, which lays a theoretical foundation for the application of the proposed method in engineering practice.

Modeling of transient flows in viscoelastic pipe network with partial blockage

Abstract In this study, transient flow and partial blockage in polyethylene (PE) pipe network are investigated experimentally and numerically using the method of characteristics in the time domain considering pipe-wall viscoelasticity. The experiments were conducted on a PE pipe network with and without partial blockage. The experimental pressure signals were damped during a short period of time in the blockage-free case. The numerical model was calibrated by the inverse transient analysis (ITA). The hydraulic transient solver calibrated with one Kelvin–Voigt element showed good consistency with the experimental results. Partial blockages with different lengths and sizes were examined at different locations of the pipe network. Results reveal an increase in head loss, pressure signal damping, and phase shift with increase in blockage. In addition, the location and characteristics of blockages with different sizes were determined using the ITA in the pipe network.

The Correlation between Lymphocyte Platelet Ratio and Gensini Score in Coronary Heart Disease Patients

The lymphocyte platelet ratio (LPR) is an inflammatory marker that can be used to identify the severity of coronary heart disease (CHD). This study aims to determine the correlation between the lymphocyte platelet ratio and Gensini scores in CHD patients. This research used correlative analytical research with a cross-sectional design . The sample was selected by consecutive sampling technique and obtained 51 respondents. The calculation of the LPR was carried out by dividing the number of platelets and lymphocytes in the volume unit of 10 3 /mm 3 . Meanwhile, the Gensini score assessment was carried out by multiplying the percentage of blockages and location of blockages based on the result of coronary angiography. Based on the Gensini score, the sample in this study was classified as mild atherosclerosis with the Gensini score <25 points, and severe atherosclerosis with the Gensini score ≥25 points. The data were analyzed using the Pearson correlation test. The result showed that the average LPR value in samples with severe atherosclerosis was 124.6 and 115.3 in mild atherosclerosis. Based on the result of statistical analysis using the Pearson test, the p-value was 0.107. It can be concluded that there is no significant correlation between the lymphocyte platelet ratio and Gensini scores in CHD patients.

PATIENT-SPECIFIC BIOFIDELIC HUMAN CORONARY ARTERY SURROGATES

Coronary artery disease (CAD) is the number one killer for both men and women in the United States. To date, unavailability of human coronary arteries due to ethical and biosafety issues has not allowed for many experimental studies on understanding the pathophysiology of CAD. Also, patient-specific arterial blockage conditions are very difficult to estimate using 2D imaging, which prevents the development of effective surgical mitigation steps. Additionally, to date, a majority of stent surgery failures (over 50%), mainly attributed to poor stent design (such as an oversized stent causing local damage of arterial wall and subsequent growth of scar tissue through the stent leading to re-blocking the artery, or in-stent restenosis), are impossible to evaluate. In the current work, a methodology to fabricate patient-specific three-layer biofidelic coronary artery surrogates was developed. This novel method involves the generation of a true-scale MRI-based patient-specific 3D arterial lumen model, which is 3D printed. A four-part silicone material system is developed, which precisely mimics the nonlinear biomechanical behavior of arterial layers, namely the intima (innermost), media (middle) and adventitia (outer). Using the 3D printed arterial lumen model as a positive mold, thin layers ([Formula: see text][Formula: see text]mm) of the layer-specific silicone-based materials are deposited, and subsequently pulled out once cured. The final product is a three-layer coronary artery model which is exactly of the same size and dimensions, and similar mechanical property as that of the actual coronary artery of a patient. Such surrogate models would be extremely helpful for cardiologists and heart surgeons to understand patient-specific atherosclerotic conditions (based on the location and size of blockages), simulate CAD-based surgeries and also evaluate stent implantation procedures. Additionally, these coronary artery surrogate models will allow stent manufacturers to design better and more reliable stents in the future to avoid stent oversizing-based arterial damage conditions and improve stent deployment techniques.

A New Method To Detect Partial Blockage in Gas Pipelines

Summary Because of its efficiency, cleanliness, and reliability, natural gas is an important sector in global energy consumption. It supplies nearly one-fourth of all energy used in the United States and is expected to increase 50% within the next 20 years. More gas-delivery infrastructure is being constructed to meet the transportation requirement of the ever-increasing demand for natural gas, while at the same time, the existing gas infrastructure is aging. Ensuring natural-gas-infrastructure reliability is one of the critical needs for the energy sector. Operators prefer to capitalize on the transportation capacity of these old pipeline systems to reduce the cost for building new pipelines, but they run a high risk of encountering partial blockage in the pipeline, which can cause operating pressure to exceed the safety specification. Therefore, the reliable and timely detection of a partial blockage in a gas pipeline is critical to ensuring the reliability of the natural-gas infrastructure. To design proper pigging tools, it is important to detect the location and size of partial blockages. Physical inspection and mathematical-model simulation are used to identify partial blockage in gas pipelines. Generally, the physical method can result in an accurate detection of the location and size of the partial blockage, but at the expense of production shutdown and high cost/long time to run the physical detection, which is a very expensive measure in a long-distance gas pipeline. The mathematical simulation detects partial blockage through numerical modeling, which could provide a quick evaluation at a much lower cost, but with higher uncertainties. Our literature review indicates that a simple, practical, and reliable method to detect partial blockage without a recorded inlet or outlet pressure is in great demand. In this study, we develop a multirate test method to detect partial blockage in a gas pipeline. By conducting multirate tests, the location and size of the partial blockage can be evaluated. The new method can be applied under the conditions of no measured inlet or outlet pressure, which have not been investigated before. It is worth locating a partial blockage under these conditions because as oil and gas exploration and production move to harsh environments, no pressure gauge being installed at the inlet or outlet of the pipeline can be a common circumstance in the fields. Even for onshore fields or fields with easy access, pressure is not transferred to the central office in real time. In addition, the metering equipment and pressure gauges installed in the pipeline may not be working. Therefore, our method provides a practical, quick, and low-computational-cost approach to estimate partial blockages corresponding to these conditions. The partial blockages in a single pipeline and in parallel/looped pipelines were evaluated in this project by use of the proposed method. Considering that most of the complicated pipeline systems under operation can be decomposed into basic units, such as single pipeline and parallel/looped pipelines, the proposed model can realistically and feasibly identify partial blockage in a complex pipeline network. Furthermore, existing studies assume only single partial blockage in the pipeline, which limits the application of available models because the detection will be misleading if there is more than one partial blockage in the pipeline. To fill this gap, we developed a model to differentiate the single-partial-blockage scenario from the multiple-partial-blockage scenario on the basis of multirate tests. The identification is critical because it guides partial-blockage detection in the right direction.

Prediction of highway blockage caused by earthquake-induced landslides for improving earthquake emergency response

Earthquake emergency response (EER) supported by the prompt assessment of seismic impact is an effective way to reduce seismic casualties and losses after an earthquake. However, in mountainous areas, highway blockages due to earthquake-induced landslides can delay EER, which, to date, EER planning has not included in assessments to identify. This paper proposes a set of rules to predict the location of highway blockages caused by these landslides. Such predictions would promote rapid implementation of traffic control plans and the prompt clearing of the blocked highways to help keep emergency efforts efficient. We propose a procedure based on the decision tree method to correlate the potential highway blockages with the earthquake-induced landslide susceptibility (ELS), which integrates the classification and quantification aspects of the ELS. Using correlation analysis, a set of rules that judge whether a highway section is likely to be blocked is proposed. These rules are based on the preexisting ELS database for China. This set of rules has been applied in a case study of the 2014 Ludian earthquake to predict the highway blockages caused by the earthquake-induced landslides. The results from this case study showed good agreement with the actual highway blockages as determined by the interpretation of unmanned aerial vehicle images. The predicted results were used to make suggestions about traffic control and blocked highway clearing for EER. The proposed set of rules appears to be effective.

Effects of different LAD-blocked sites on the development of acute myocardial infarction and malignant arrhythmia in a swine model.

To explore the effects of various left anterior descending (LAD) artery-blocked sites on the development of acute myocardial infarction (AMI) and malignant arrhythmia in a swine model. Twenty-two pigs underwent occlusion of the coronary artery with balloon angioplasty were randomly divided into three groups according to the blocked site of the balloon: middle-site-blocked LAD group, bottom-third-blocked LAD group and control group. Then, the development of AMI and malignant arrhythmia, including ventricular tachycardia and ventricular fibrillation during the process of model creation, were recorded. Changes of the hemodynamics, blood gas analysis, electrocardiography, and myocardial enzymes were analyzed in each group before and after occlusion. Middle-site-LAD blockage resulted in a larger infarction size and the corresponding incidence of ventricular fibrillation was significantly higher than that of the bottom-third-blocked group (P<0.05). After the occlusion, the QTc interval of the Middle-site-blocked LAD group was significantly longer than that in the other groups (P<0.01). Moreover, mean arterial blood pressure (MAP), left ventricular ejection fraction (LVEF), and partial pressure of oxygen (PaO2) were significantly lower, but partial pressure of carbon dioxide (PaCO2) increased, in the Middle-site-blocked-LAD group compared with that in the bottom-third-blocked group (P<0.01). Compared with the control group, the two LAD-blocked groups showed significantly higher levels of Mb, CK-MB, LDH, AST and cTnT (P<0.01) four hours after the artery occlusion. However, these indexes were not significantly different between the two LAD-blocked groups (P>0.05). Location of LAD blockages in swine models may affect the development of AMI and malignant arrhythmia.

ACOUSTIC SENSORS TO DETECT CLOGS IN SEWER PIPELINES

Blockages in sewage pipelines are difficult to be cleaned or extracted. In order to manage sewer blockage proactively sewer managers needs to be able to identify the location of blockages precisely. As of now, only humans do this sully job of cleaning the sewages. Many human right organizations have been advocating to stop this inhuman activity. Even the highest court in the land has admonished the government to stop forth with this job of cleaning. Respective government’s corporation is adapting cleaning machines to suck the clogs and sewage water from respective blockage points. As an alternative solution, using modern technology, we present our paper on how an acoustic based sensor could be used to detect the blockages automatically as well as transmitting this information using the wireless sensor network to the centrally monitored server system. This will help in taking immediate action of removing the clogs instantly. This will not only save cost but also enable instant solution.

Rapid detection of sewer defects and blockages using acoustic-based instrumentation

Sewer flooding incidents in the UK are being increasingly associated with the presence of blockages. Blockages are difficult to deal with as although there are locations where they are more likely to occur, they do occur intermittently. In order to manage sewer blockage pro-actively sewer managers need to be able to identify the location of blockages promptly. Traditional closed-circuit television (CCTV) inspection technologies are slow and relatively expensive so are not well suited to the rapid inspection of a network. This is needed if managers are to be able to address sewer blockages proactively. This paper reports on the development of an acoustic-based sensor. The sensor was tested in a full scale sewer pipe in the laboratory and it was shown that it is able to find blockages and identify structural aspects of a sewer pipe such as a manhole and lateral connection. Analysis of the received signal will locate a blockage and also provide information on its character. The measurement is very rapid and objective and so inspections can be carried out at much faster rates than using existing CCTV technologies.

A description of gender differences in angiographic findings in a single-center Iranian hospital

Coronary angiography is one of the most common hospital procedures, though there is limited information on the location and extent of coronary artery blockages other than for predominately White patients. This study examined the location and magnitude of coronary artery blockages in patients admitted to a leading tertiary heart hospital in Iran with symptoms of coronary artery disease (CAD). This retrospective descriptive study aimed to review angiography records of all patients with symptoms of CAD undergone diagnostic coronary angiography between February 2002 and September 2004. A total of 94 consecutive angiographic records were analyzed to determine the culprit coronary arteries and the severity of CAD. The findings of the study showed that double- vessel disease was the commonest type of CAD. The left anterior descending (LAD) artery was the most common culprit artery (84%), followed by RCA (64%), CX (37%), OM (13%) and LMS (3%). Our study showed a relatively high angiographic prevalence of LAD blockages. The results of this study provide additional support for the significance of ethnicity in the extent of coronary artery blockages.

Testing in the Noninvasive Vascular Laboratory

The circulatory system is made up of the heart and blood vessels. The heart is the pumping organ that circulates blood through the vessels. There are 3 major types of blood vessels: arteries, which carry oxygen-rich blood to the organs and limbs; veins, which return blood from the organs and the limbs to the heart to be resupplied with oxygen by the lungs; and the lymphatics, which return fluid from the skin and tissues to the veins. Disorders of the blood vessels are common, and there are many different vascular disorders (Table 1). After a doctor’s physical examination, testing in the vascular laboratory is often the first step in diagnosing vascular disease. View this table: TABLE 1. Common Disorders of Blood Vessels The most common disorder of the arteries is atherosclerosis, or clogging of the arteries with cholesterol-rich plaque, and it can occur in almost any artery of the body. The symptoms of atherosclerosis depend on the location of the blocked arteries. Aneurysm, or severe enlargement of a blood vessel, is another common disorder of arteries. The most common location for an aneurysm is the abdominal portion of the aorta. This abnormality is known as abdominal aortic aneurysm. The aorta is the largest artery that delivers blood from the heart to the rest of the body through its branches. There are also many disorders of the veins. Deep vein thrombosis is a serious disorder that usually requires immediate treatment. Deep vein thrombosis most frequently occurs in the veins of the legs, but it also can develop in the veins of the arms or the abdomen. Varicose veins are bulging veins that appear on the legs, may be unsightly, and may cause discomfort. Venous insufficiency is the term used to describe damaged veins that allow backward flow of blood down the …

Characterizing holes in duct walls using resonance frequencies.

The current paper demonstrates that the technique recently used by de Salis and Oldham for the sizing and location of blockages in ducts using resonance and antiresonance value shifts [J. Sound Vib. 221(1), 180-186 (1999)] may be successfully applied to the detection, location, and sizing of small holes in duct walls. It is shown that when the blockage area function reconstruction process is applied using resonance and antiresonance frequencies determined from a single measurement of sound pressure within a duct, the position of a hole in the duct wall is revealed as the beginning of an apparent gradual expansion. This expansion is termed the effective expansion function and emanates from an initial positive dc shift. Once the hole has been located, a simple impedance model of the duct incorporating the hole location and the measured wave number at the first-order duct resonance may be derived which allows the determination of the radius of the side hole from a simple quadratic equation. This hole-sizing technique is also successfully applied to thin slits in duct walls using an equivalent radius approach, and is shown to be highly accurate for slit-shaped holes with cross-sectional length to width aspect ratios of up to 28:1.

DNA sequence specificity of mitoxantrone.

An in vitro transcription assay was used to determine the sequence specificity of binding of mitoxantrone to a 497 bp fragment of DNA containing the lac UV5 promoter. Transcriptional blockages of the E. coli RNA polymerase were observed dominantly prior to 5'-CpA sequences (64% occurrence), and to a lesser extent 5'-CpG sequences (29%). Overall, 93% of all blockage sites were prior to pyrimidine (3'-5') purine sequences. An effect of flanking sequences was evident since the blockage sites contained an A/T base pair 5' prior to the consensus CpA and CpG intercalation sites. The consensus sequences for the preferred mitoxantrone intercalation sites are therefore 5'-(A/T)CA and 5'-(A/T)CG. The location of transcriptional blockages one base pair prior to the intercalation site is consistent with the fact that the mitoxantrone side chains lie in the major groove.

Determination of blocking locations and cross-sectional area in a duct by eigenfrequency shifts

A theoretical determination of the location and size of blockages in the one-dimensional duct has been carried out. It is found that the blockage cross-section area function can be calculated from the measured eigenfrequencies obtained using two boundary conditions, i.e., closed–closed (or open–open) and closed–open ends. When the blockages are small, the area function of the blocked duct can be expressed as a one-dimensional spatial Fourier transform, whose spatial frequencies are related to the eigenfrequency shifts caused by the blockages in the duct. The method developed can be applied to the detection of the multiple blockages. The experimental results show that the accuracy of the calculated blockage area function is dependent on the number of the eigenfrequencies used. The agreements between the calculated blockage area and the actual blockage are excellent when the half-wavelength of the eigenfrequency used is greater than the length of the blockage.