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Unileg-type thermoelectric generators have proven to be a good choice for hightemperature applications, because their composition from a single thermoelectric material avoids different thermal expansion coefficients, giving the structure good mechanical strength and increased lifespan during thermal cycling. These structures are usually composed of a thermoelectric pellet with metallic electrical conductors joining the hot and cold ends of consecutive pellets. The novel unileg structure described herein is designed to deal with one of the main issues with traditional devices, viz. the physical and chemical stability of the solder between the pellet and the conductor at the hot side. The material for which this structure is proposed is a p-type Ca 3 Co 4 O 9 semiconductor oxide, due to its chemical stability at high temperature and good machinability. This final requirement is related to the main innovation of the structure, viz. a partial cut that divides the pellet longitudinally, leaving two legs joined by an uncut section, forming a section similar to the letter . The metallic conductor stripe usually employed in unileg thermoelectric generator manufacturing is replaced by a coating of conductive material, in this case silver, on one of the legs resulting from the cut. Due to these operations, one of the legs is practically short-circuited and acts as an electrical conductor for the unileg structure, eliminating the need for soldering at the hot end of the pellet.

Hydraulic fracturing in multi stage horizontal unconventional wells is perhaps one of the most important if not the most important in the drilling and completion cycle of these wells. It's also the most applied technique repeatedly in multiple formations throughout the world and yet the question that looms large over us, do we understand the fracture geometry in these unconventional environments.Year on year most unconventional formations seem to fall in line with the industry trend of increasing lateral lengths and pumping more stages to improve production and recovery. Again, we need to ask ourselves if this is sustainable. Introspection of data available from public data seems to indicate that a significant chunk of these wells buck the trend of increased lateral lengths and stages and we still continue to apply these techniques especially in a price sensitive oil market. What if we could challenge this paradigm through a systematic engineering process that could relate the impact of fracture geometry and well spacing? We selected one of the up and coming plays in Canada that is on the road to development called the Duvernay.The Duvernay Formation is a unit of the Woodbend Group and is considered as the source rock for prolific reservoirs such as the Leduc reefs. Duvernay formation holds an estimated 443 trillion cubic feet of gas and 61.7 billion barrels of oil.This paper is an attempt to model and understand complex hydraulic fractures in a multi well pad environment coupled with production modelling to understand drainage patterns. Public data from the IHS database was used to construct and build a geocellular model and wells that had petrophysical and geomechanical data were used to build a representative well pad model. Using the model built complex fractures using the unconventional fracture models were simulated in a multi well pad environment. Impact on reservoir drainage has been assessed with various simulations by changing different parameters with respect to hydraulic fracturing. The results of these various simulations are presented in the paper and these simulations act as a tool to understand when possible interference may occur in these pads. Spacing of wells and frac sizes can be adjusted to minimize competitive drainage between wells.

Ca 2.93 Sr 0.07 Co 4 O 9 bulk textured samples have been successfully prepared by hot uniaxial pressing, followed by a thermal treatment at 800ºC under air between 0 and 1532 h. The microstructural, thermoelectric and mechanical properties as well as density of all the samples were evaluated as a function of the thermal treatment length. Scanning electron microscope characterization has shown that samples are mainly composed by Sr-doped Ca 3 Co 4 O 9 thermoelectric (TE) phase, accompanied by minor amounts of Sr-free Ca 3 Co 2 O 6 secondary phase. After an initial decrease of density after the first aging treatment, it remains practically constant for longer times. This behaviour is reflected in the mechanical properties, which slightly decrease after 12 h thermal treatment, when compared with the as-hot pressed ones, and remain practically constant for larger times. However, TE properties are not affected by the aging process, and are within the typical errors, independently of the aging time. Moreover, power factor values at 850ºC are between the highest obtained so far in this kind of materials (> 0.60mW/K 2 m) 2

There are three principal sources of noise and vibration in electrical machines: electromagnetic sources, mechanical sources, and aerodynamic sources. Nowadays, one of the major advantages of permanent-magnet synchronous machines is their torque density. This density is achieved through a high magnetic flux density in the air gap, which is achieved through hard magnets. Unfortunately, in these machines, electromagnetic forces have been identified as the main source of vibration and noise, and high magnetic flux densities make these vibrations and noises more significant. With the aim of better understanding the relationship between electromagnetic forces and design variables, this article, which is the continuation of previous work, firstly describes a study of the sources of magnetic forces in permanent-magnet synchronous machines. Subsequently, an analytical model for the computation of the radial forces originating from electromagnetic sources in permanent-magnet synchronous machines is stated. This model analyzes the forces on both the rotor surface and the base of the stator tooth. The analytical results were corroborated through simulations using the finite element method (FEM) and also by experimental tests performed over two prototypes. The results achieved by the analytical model show good agreement with both FEM results and experimental measurements.

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