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Copyright of Revista Facultad de Ingeniería - UPTC is the property of Universidad Pedagogica y Tecnologica de Colombia, Facultad de Ingenieria and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

High-pressure and low-temperature conditions in deep-water development are probably going to cause serious hydrate deposition problems. Current studies on hydrate migration and deposition are mainly centered on through-diameter conditions, and relatively few studies have been carried out for reduced-diameter conditions. Meanwhile, the effect of heat transfer between the particle-fluid-wall in the pipe on hydrate particle deposition is usually neglected, resulting in discrepancies between results and reality. Here, an improved hydrate deposition-stripping model is developed based on hydrate particle adhesion and rebound as well as deposition and stripping criteria, and combined with the inter-phase heat transfer characteristics. The effects of several important parameters, such as thermophoretic force and pipeline structure, on the deposition characteristics of micron-sized hydrate particles were investigated, and the deposition mechanism of hydrate in special pipelines was revealed. Also, the combination of calculation results provides new ideas for the design of oil and gas pipes. Based on the enhanced mechanism of hydrate particle deposition in the reduced-diameter pipe proposed in this paper, a new parameter of hydrate particle deposition enhancement rate (ξ h) is defined to characterize the integrated enhancement effect of reduction structure and heat transfer in the pipe on hydrate particle deposition, and a new correlation calculation method is provided for it. The results can provide a valuable reference for efficient and accurate calculation of hydrates. • An improved hydrate deposition-stripping model considering particle-fluid-wall heat transfer was developed. • The reduction of pipe resulted in an enhanced temperature gradient, which triggered a thermophoretic effect on the deposition of micron-sized hydrate particles. • The circular transition was less efficient in heat transfer and hydrate particle deposition than the straight-angle transition. • Three enhanced mechanisms for hydrate particle deposition in heat-transfer pipes with diameter reduction were proposed. • An empirical formula for hydrate particle deposition enhancement rate was developed. [ABSTRACT FROM AUTHOR]

Copyright of Special Oil & Gas Reservoirs is the property of Special Oil & Gas Reservoirs Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The details of making technology of porous permeable material with use of wire are allowed to carry out the analytical research of structure and structural characteristics of wire winding body. Its permit for prognostication the final properties of material, that is produced by the following deformation treatment (diameter reduction). Due to the regular organized arrangement of wire, the coil of winding body is considered as a multispan continuous beam, but a contact of coils - as interaction of two cylinders. Possibility of exactly calculation of the contacts between coils is allowed to go over the single fragment displacements into deformation of whole winding body. During research of deformation processes in regards of winding body geometry and used wire mechanical properties, the structural characteristics of porous permeable wire material are expected. The optimal number of winding layers, eliminating the distortion of organized final structure, is established. The material pressure-compactness relation is obtained in order to control the technological conditions of winding and drafting for guarantee the product required properties.

The details of making technology of porous permeable material with use of wire are allowed to carry out the analytical research of structure and structural characteristics of wire winding body. Its permit for prognostication the final proper-ties of material, that is produced by the following deformation treatment (diameter reduction). Due to the regular orga-nized arrangement of wire, the coil of winding body is considered as a multispan continuous beam, but a contact of coils – as interaction of two cylinders. Possibility of exactly calculation of the contacts between coils is allowed to go over the single fragment displacements into deformation of whole winding body. During research of deformation processes in regards of winding body geometry and used wire mechanical properties, the structural characteristics of porous permea-ble wire material are expected. The optimal number of winding layers, eliminating the distortion of organized final struc-ture, is established. The material pressure–compactness relation is obtained in order to control the technological condi-tions of winding and drafting for guarantee the product required properties.

Chemical machining is one of the oldest nontraditional machining processes. It applies chemical etchant to machine material. The method is very basic and economical to produce complex geometrical parts from thin sheet materials. The application of this method to cylindrical parts is not common. In this study, chemical machining process was employed to machine rod as cylindrical part. The selected material was St37 with diameter of 10 mm. The experimental study implemented ferric chloride, which is known a universal chemical etchant for ironbased materials, at three different etchant solutions in two chemical machining temperatures (30 °C and 50 °C). The experimental setup is based on upright drilling machine that has three different spindle speed values (250, 500, and 1500 rpm). It was observed that lower etchant concentration provided higher diameter reduction, surface roughness, and cylindricity. Moreover, the effect of chemical machining temperature is examined and increase of this value produced faster machining. [ABSTRACT FROM AUTHOR]

Chemical machining is one of the oldest nontraditional machining processes. It applies chemical etchant to machine material. The method is very basic and economical to produce complex geometrical parts from thin sheet materials. The application of this method to cylindrical parts is not common. In this study, chemical machining process was employed to machine rod as cylindrical part. The selected material was St37 with diameter of 10 mm. The experimental study implemented ferric chloride, which is known a universal chemical etchant for ironbased materials, at three different etchant solutions in two chemical machining temperatures (30 °C and 50 °C). The experimental setup is based on upright drilling machine that has three different spindle speed values (250, 500, and 1500 rpm). It was observed that lower etchant concentration provided higher diameter reduction, surface roughness, and cylindricity. Moreover, the effect of chemical machining temperature is examined and increase of this value produced faster machining. [ABSTRACT FROM AUTHOR]

Copyright of Management Systems in Production Engineering is the property of Sciendo and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Abstract: One major limitation of the electrospinning technique for generating polymer fibers is the large average diameter and the broad diameter variability of electrospun fibers. Improved methods of controlling fiber diameter and variability will have implications for many applications ranging from filtration to cell and tissue engineering. Here we report an effective method of reducing the diameter and variability of fibers prepared from three different polymers, poly(ethersulfone), poly(caprolactone), and poly(caprolactone-co-ethyl ethylene phosphoester), by doping polymer solutions with a positively charged amphiphile, octadecyl rhodamine (R18) or octadecyltrimethylammonium bromide (OTAB) at 5000:1 to 20:1 of polymer to amphiphile weight ratio. This is due to the combined effect of field-driven surface partitioning of positively charged amphiphiles and surface tension reduction. This method of diameter reduction can be applied easily without modifying the electrospinning setup or changing the polymer–solvent system. [Copyright &y& Elsevier]

Abstract: The tube has high bending and torsional rigidity considering its weight. Thus, tubular products are effective industrial parts to reduce their weight and their employments volume is increasing. Spinning is a very effective and flexible manufacturing technology for short production runs in a variety of sizes and shapes. Spinning is widely applied to the tube forming corresponding to the increasing usage of the tubular parts. Magnesium and its alloys have many good properties as strength to weight ratio, vibration absorbability and excellent recyclability. It is very difficult to form the magnesium alloy to various shaped products. But, it is easy to form the alloys at high temperature. Therefore, authors have invented new Computer Numerical Control (CNC) spinning machine, which has roller tools with heaters. The heated tools heat and form the magnesium tubes into various shapes by the spinning. The forming possibility of magnesium tube and the properties of formed tube are made clear in this paper. [Copyright &y& Elsevier]

Although nanotheranostics have displayed striking potential toward precise nanomedicine, their targeting delivery and tumor penetration capacities are still impeded by several biological barriers. Besides, the current antitumor strategies mainly focus on killing tumor cells rather than antiangiogenesis. Enlightened by the fact that the smart transformable self-targeting nanotheranostics can enhance their targeting efficiency, tumor penetration, and cellular uptake, we herein report carrier-free Trojan-horse diameter-reducible metal-organic nanotheranostics by the coordination-driven supramolecular sequential co-assembly of the chemo-drug pemetrexed (PEM), transition-metal ions (Fe III ), and antiangiogenesis pseudolaric acid B. Such nanotheranostics with both a high dual-drug payload efficiency and outstanding physiological stability are responsively decomposed into numerous ultra-small-diameter nanotheranostics under stimuli of the moderate acidic tumor microenvironment and then internalized into tumor cells through tumor-receptor-mediated self-targeting, synergistically enhancing tumor penetration and cellular uptake. Besides, such nanotheranostics enable visualization of self-targeting capacity under the macroscopic monitor of computed tomography/magnetic resonance imaging, thereby realizing efficient oncotherapy. Moreover, tumor microvessels are precisely monitored by optical coherence tomography angiography/laser speckle imaging during chemo-antiangiogenic therapy in vivo , visually verifying that such nanotheranostics possess an excellent antiangiogenic effect. Our work will provide a promising strategy for further tumor diagnosis and targeted therapy.

Electrospinning is one of the most facile and versatile techniques to prepare polymer fibers ranging from micrometers to nanometers. Although several parameters can be tuned to control the sizes and morphologies of electrospun fibers, many obstacles are still encountered as the target sizes of the fibers are getting smaller; for example, the sizes of the fibers can be effectively reduced by lowering the polymer solution concentrations but beaded or beads‐on‐string structures are usually formed. To overcome such obstacles, here a simple technique to prepare alignment‐improved and diameter‐reduced fibers without bead formation by hot‐stretching electrospun fibers at temperatures higher than the glass transition temperatures of the polymers is developed. Polystyrene and poly(methyl methacrylate) are both used in this work as model materials. The relationship between the draw ratio and diameter of the fibers is quantitatively analyzed, demonstrating the control of the fiber diameters. Moreover, higher degrees of alignment improvement at the middle part of the fibers than those at the end part is observed, which results in lower water contact angles at the middle part of the fibers. This work provides a useful post‐treatment technique to control the sizes and orientations of electrospun polymer fibers. [ABSTRACT FROM AUTHOR]