El actual diseño de sarta de varillas de succión parte del principio que asume que una sarta de varillas es expuesta a una carga simple de tensión, cuyo objetivo es mantener el mismo estrés modificado en la parte superior de cada cono. La mejora que hasta ahora se había propuesto en el diseño de la varilla consistía en conseguir el mismo grado de seguridad en cada sección, utilizando una distribución dinámica de la fuerza proporcional a lo largo de toda la sarta. Sin embargo, los procedimientos disponibles no proporcionan la pre-cisión deseada para un análisis pertinente y los operadores no pudieron identificar los fenómenos específicos que se producen en los pozos de CBM. En el presente trabajo se desarrollan modelos matemáticos de las cargas las varillas y en la sarta de varillas basados en la naturaleza periódica de carga en la sarta de varillas; el método de resistencia a la fatiga es utilizado para diseñar una única sarta de varillas; y la sarta de varilla cónica está diseñada para obtener la misma tensión en cada una de las partes superiores de cada sección. Sus características de aplicación se demuestran con el ejemplo de los pozos de CBM en la Cuenca de Ordos. Las interpretaciones de los resultados muestran que el diseño anterior daba a las varillas individuales un mayor diámetro y a las varillas en la sarta un mayor porcentaje que el del método propuesto. El cálculo debería enfocarse en la inercia, la vibración y las fuerzas de fricción para ilustrar la propagación de los esfuerzos elásticos en el material de la varilla con la velocidad del sonido. La sarta única debe ser diseñada usando medidores de resistencia de fatiga debido a la tensión pulsante asimétrica de la carga de varilla; y la sarta cónica debe tener un diseño equilibrado que permita fijar una igual resistencia a la fatiga en cada sección. Una longitud de carrera más corta da un mayor porcentaje de la varilla cónica y un aumento de los resultados de la capacidad de carga a un diámetro de varilla mejorado. El diámetro de la varilla aumenta con el tamaño de la bomba y la capacidad de carga de la sarta única; y el porcentaje de la varilla cónica en las cuerdas de varillas superiores aumenta con el diámetro del émbolo para la sarta cónica. La presente investigación busca mejorar la eficiencia del sistema de bombeo, asegurar buenas condiciones de funcionamiento, y reducir los costos totales de producción.

The existing design of sucker rod string mainly focuses on the simplifying assumptions that rod string was exposed to simple tension loading. And its goal was to have equal modified stress at the top of each taper. The improved rod design was to have the same degree of safety at each section, and it used a dynamic force distribution that was proportional along the whole string. Moreover, the available procedures did not provide the desired accuracy of its pertinent analysis, and the operators could not identify the specific phenomena that occur in CBM wells. In this paper, the mathematical models of rod loads and string length were developed based on the cyclic nature of rod string loading. And the fatigue endurance method is utilized to design the single rod string, and the tapered rod string is designed to have an equal equivalent stress at the top of each section. Its application characteristics are demonstrated by the example of CBM wells in Ordos Basin. The interpretations of results show that the previous design gave the single rods a larger diameter and the top rods in the string a greater percent than the proposed method would dictate. The calculation should concern about inertial, vibration and friction forces to illustrate the elastic force waves travelling in the rod material with the speed of sound. The single string should be designed using fatigue endurance ratings due to asymmetric pulsating tension of rod loading. And the tapered string involves a balanced design by setting the fatigue endurance at each section equal. A shorter stroke length gives a greater rod taper percentage and an increased load capacity results to an enhanced rod diameter. The rod diameter increases with the pump size and load capacity for the single string, and the rod taper percentage of the top rod strings increases with plunger diameter for the tapered string. The proposed research improves efficiency of the pumping system, assures good operating conditions, and reduces total production costs.

Our objective was to investigate the distributions of six single nucleotide polymorphisms (SNPs) MS4A2 E237G, MS4A2 C-109T, ADRB2 R16G, IL4RA I75V,IL4 C-590T, and IL13 C1923T in Mauritian Indian and Chinese Han children with asthma. This case-control association study enrolled 382 unrelated Mauritian Indian children, 193 with asthma and 189 healthy controls, and 384 unrelated Chinese Han children, 192 with asthma and 192 healthy controls. The SNP loci were genotyped using polymerase chain reaction (PCR)-restriction fragment length polymorphism for the Chinese Han samples and TaqMan real-time quantitative PCR for the Mauritian Indian samples. In the Mauritian Indian children, there was a significant difference in the distribution of IL13 C1923T between the asthma and control groups (P=0.033). The frequency of IL13 C1923T T/T in the Mauritian Indian asthma group was significantly higher than in the control group [odds ratio (OR)=2.119, 95% confidence interval=1.048-4.285]. The Chinese Han children with asthma had significantly higher frequencies ofMS4A2 C-109T T/T (OR=1.961, P=0.001) and ADRB2 R16G A/A (OR=2.575, P=0.000) than the control group. The IL13 C1923T locus predisposed to asthma in Mauritian Indian children, which represents an ethnic difference from the Chinese Han population. TheMS4A2 C-109T T/T and ADRB2 R16G A/Agenotypes were associated with asthma in the Chinese Han children.

Objective: the purpose of this study was to report the authors' experience in the diagnosis, management, and clinical outcome of intestinal ischemia with pneumatosis intestinalis (PI) and hepatic-portal-mesenteric venous gas (HPMVG). Experimental design: a retrospective analysis. Method: the medical records of 12 cases of intestinal ischemia with PI and HPMVG spanning the last 10 years were reviewed. Clinical characteristics, imaging study results, surgical findings, histological findings, management, and clinical outcome were evaluated. Results: of the 12 cases that were evaluated, 9 patients presented with abdominal distension, three, with abdominal pain, five, with shock on admission, and six, with fever. Most patients (83%) had a history of diabetes mellitus. Dilated loops of bowel were identified on plain film radiography in 9 of 12 of patients. Only 3 cases were initially suspected of having abnormal gas over the RUQ or intramural intestine. All patients underwent abdominal computed tomography (CT). Nine patients were diagnosed with ischemic changes of the intestine (2 cases had colon involvement), and 3 patients were found to have a gangrenous intestine. While all patients underwent segmental resection of the intestine, ten of 12 patients died post-operatively. Conclusions: abdominal CT findings of PI and HPMVG in intestinal ischemia do not appear to either directly correlate with the gross findings or predict clinical outcome. The clinical outcome of patients affected with this condition was poor, even following surgical intervention. A positive clinical outcome may depend on the severity and extent of the underlying disease(s).