No abstract

Ni rich LiNi0.8Mn0.1Co0.1O2 (NMC811) is one of the most promising cathode materials for high energy all solid-state batteries. However, its poor ionic and electronic conductivity along with high interfacial instability with thiophosphate-based solid electrolytes result in severe capacity loss with cycling. In this paper, a polyacrylonitrile (PAN) coating is applied on the surface of NMC811 followed by a simple heat treatment in air. The PAN coating layer not only helps to improve the electronic conductivity of the cathode composite but also prevents the direct contact of NMC811 active material with the solid electrolyte, reducing the decomposition of the electrolyte and formation of passivating layers with low ionic conductivity. Compared to pristine NMC811, the electrochemical properties of PAN-NMC composites are significantly improved. When cycled at 0.1C rate, the PAN-NMC composite shows an initial capacity of 192.16 mAh g-1 and capacity retention of 68.5% over 100 cycles compared to the lower capacity of 173.06 mAh g-1 and retention 58.68% for the pristine NMC811. These results indicate that the PAN coating greatly improves the conductivity and cycling performance of NMC811.

Chlorinated polyethylene elastomers, a relatively new series of polymers, are derived from a high density polyethylene backbone which has been chlorinated via a free radical aqueous slurry process. Polymers are available which vary in percent chlorine (36-48%), in molecular weight, and in inherent crystallinity. Unfortunately, these basic polymer properties are inadequate to describe the performance of chlorinated polyethylene elastomers on a practical basis. The current study characterizes chlorinated polyethylene elastomers as general purpose oil, heat and ozone resistant elastomers. Reference is made to more familiar rubbers for comparative purposes only. Once the polymer's position within the above frame of reference is established, the technology with which one compounds chlorinated polyethylene for specific properties is investigated. Because of the saturated polymer chain, the necessity of free radical curing systems is outlined. Both black and non-black filler systems are introduced. This flexibility gives the compounder an excellent balance of properties including a realistic service temperature from —60° F to 300° F.

In this study, a glass reinforced vinyl ester (GRV) liner was systematically designed to produce a corrosion resistant, toughened, liner with superior corrosion resistance and strength characteristics. This GRV liner system was designed as an alternative to previously tested glass reinforced epoxy systems [1]. The composite liner could theoretically be used in conjunction with standardized oil and gas production tubing to alleviate the effects of corrosion in offshore exploration applications. This particular system was designed using netting analysis for filament wound pressure vessels and tested in accordance with ASTM D2290 split-disk procedures. To ensure that the finalized design would be capable of withstanding the immense pressures and temperatures seen during use in offshore oil and gas production, the project used an API controlled steel alloy already employed by industry as a benchmark for determining the necessary yield stress and internal yield pressure required for the proposed application. To further define the physical characteristics of the proposed system, tests were conducted to verify the coefficient of thermal expansion (CTE) of the composite material. The CTE data was then used to evaluate the potential for interfacial thermal stresses induced when bonding dissimilar materials at elevated temperatures. Furthermore, the vinyl ester composite was environmentally conditioned in accordance with ASTM G202 rotating cage procedures, and evaluated to assess the proposed system's susceptibility to degradation caused by corrosive fluids. The study was conducted with the intent to utilize the design principles of filament wound pressure vessels to produce an oil and gas production liner that emulates the strength characteristics of its steel counterpart, while retaining the corrosion resistance associated with vinyl ester matrix.

In recent years, an industry-wide demand for increased drilling efficiency has led to the development of technologies and methods focused on multi-well pad development and the minimization of the transportation of drilling rigs between locations. Studies have indicated the potential for improving drilling cycle efficiency through improvements in rig design and procedural documentation but have given limited consideration to the unitization and mobilization practices surrounding ancillary components such as mud pumps, light plants, bulk fluid storage and other systems that comprise modern land rigs. This study examines current unitization practices, as well as offers alternative methods of integrating ancillary system components to improve current transport configurations. Specifically, ancillary systems whose transport dimensions and weight exceed the federal and state requirements for commercial vehicles operating within the National Highway Freight Network (NHFN). In this study, the application of transport logistics software is used to demonstrate that there exists the potential for significant reduction in land rig mobilization costs through revised unitization of drilling rig ancillary systems. Permit data from proposed wells located in the Permian, Bakken, and Marcellus are utilized to develop transport scenarios whose focus is to quantify the impact of ancillary system unitization on the total fee structure associated with rig mobilization between geographical regions. Within each scenario, ancillary systems from currently active rigs are compiled and itemized according to their weight, transport dimensions, and degree of component unitization. The resulting schedule is then processed through transport logistics software to identify fee schedules associated with oversize permits, overweight permits, civilian and police escorts, driver rate/fuel costs, and associated service fees for the individual loads. Following the conclusions derived from the analysis of the existing rig systems, the series of transport scenarios are repeated using revised component configurations. The revised system employs a combination of divisible and non-divisible loads whose components are either integrated as part of dedicated transport trailers or located within ISO containers loaded onto commercially available transport trailers. The fee schedules from active rigs, as well as the results from the proposed unitization, are explored in detail to identify critical areas for improvement regarding unitization practices for active rigs and future builds.