The buckling behavior of rod strings in wellbore is one of the key issues in petroleum engineering. The slender rod strings in vertical wellbore were selected as research objects. Based on the energy method, the critical load formulas of sinusoidal and helical buckling were derived for the string with the bottom of the wellbore pressure. According to the sinusoidal and helical buckling’s geomet...

This paper presents a new approach for hinterland modelling based on the results of port choice modelling. The paper follows the idea that the shippers’ port choice is a trade-off between various objective and subjective factors. The presented model tackles the problem by applying the AHP method in order to obtain ports’ preference rates based on subjective factors, and combine them with object...

background iodinated x-ray contrast media are the most commonly used contrast agents in the world with an annual application of 40-50 million. new non-ionic con- trast agents are subdivided into low osmolar agents such as iopromide and iso-osmolar agents such as iodixanol. regarding different biochemical characteristics, these agents are different in the allergic reactions and contrast enhancem...

BACKGROUND Recently, single-port video-assisted thoracic surgery (VATS) has been proposed as an alternative to the conventional three-port VATS for primary spontaneous pneumothorax (PSP). The aim of this study is to evaluate the early outcomes of the single-port VATS for PSP. METHODS VATS was performed for PSP in 52 patients from March 2012 to March 2013. We reviewed the medical records of th...

Let f be a number-theoretic function. A finite set X of natural numbers is called f -large if card(X) ≥ f(min(X)). Let PHf be the Paris Harrington statement where we replace the largeness condition by a corresponding f -largeness condition. We classify those functions f for which the statement PHf is independent of first order (Peano) arithmetic PA. If f is a fixed iteration of the binary lengt...

Micro and nanoscale mobile agents capable of self-propulsion in low Reynolds number fluids would have a great technological impact in many fields. Few known mechanisms are able to propel such devices. Here we describe helical nanobelt (HNB) swimmers actuated by an electric field-generated electro-osmotic force. These HNB swimmers are designed with a head and a tail, similar to natural micro-org...

PURPOSE The present study was conducted to investigate the proportion and clinical outcomes of breast cancer patients who did not receive postoperative radiotherapy (PORT) after breast-conserving surgery (BCS). METHODS This retrospective study included all breast cancer patients received curative BCS without PORT between 2003 and 2013. In the PORT omission group, characteristics and local rec...

BACKGROUND We conducted a study of participants' abilities to place a laparoscopic port for in vivo biosensor use. Biosensors have physical limitations that make port placement crucial to proper data collection. A new port placement algorithm enabled evaluation of port locations, using segmented patient data in a virtual environment. METHODS Port placement scoring algorithms were integrated i...