Steady State Analysis Of Single Phase IPM Motors By D-Q Harmonic Balance Method

A concise steady-state analysis of a single-phase line-start permanent magnet (SPLSPM) machine is conducted from a developed d-q model using the d-q harmonic balance technique. The d-q model was developed in rotor reference frame from a phase variable model of the machine. SPLSPM whose performance indices were characterized by high torque ripples has detailed analysis docile mostly in computer simulations quite unlike the three-phase types. The main cause is not far-fetched, it was due to nonexistence of precise mathematical model in d-q rotor frame of the motor due to the unbalanced field winding, the rotor saliency and the presence of the capacitor in the auxiliary windings. Even after model has been developed, the simple traditional procedure of setting all time varying component to zero for steady-state analysis fails because the rotor position dependence on the inductance expressions could not be eliminated. The d-q harmonic-balance technique was then applied. An important feature of the harmonic balance technique was that it decoupled all equations to simple sine waveforms in a style that resembled Fourier series. Results yield torque pulsation, current and load characteristics in the steady state

Microplastics in silver catfish (Chrysichthys nigrodigitatus) from new Calabar River in Niger Delta, Nigeria

This study investigated the ingestion of microplastics by silver catfish (Chrysichthys nigrodigitatus) from New Calabar River in Niger Delta, Nigeria. Microplastics from the guts of 45 fish were examined with microscope after dissolution with potassium hydroxide. Microplastics, mostly fragments were found in about 56% of the samples at an average of 3.87±5.97 particles per fish. This study highlights the consequences of plastic pollution in freshwater environment and the potential risk to aquatic and human life. This also shows a potential threat to public health and therefore needs attention from health and environmental policy makers

A gaming simulation approach to understanding blue ocean strategy development as a transition from traditional competitive strategy

Blue Ocean Strategy (BOS) has attracted a resurgence of interest following various market discontinuities, including digital disruption, the growth of the sharing economy and the development of ecosystems. BOS is a combination of value innovation and new markets, driving sustained higher performance through specific marketing activities, but it is difficult to conceive and implement. We outline five cases that use various transition paths to BOS through white spaces - with product extensions in the existing market. An important part of this transition are ‘blue ocean droplets’ which drive profitable growth through the transition and then onto a successful deployment of a blue ocean strategy. Blue ocean droplets drive profitable growth - simultaneously increasing volume sales, maintaining/increasing prices and maintaining/decreasing costs. We then use an inductive qualitative approach in a multi-team gaming simulation to examine drivers of firm performance. Higher than average performance is driven by repositioning in white spaces and execution of the three blue ocean droplets. Finally, we discuss implications for firms: execute a number of real options to follow one of several transition paths to a full BOS. This approach involves less downside risk than a full BOS approach, but can still be sustainably profitable, while also breaking the traditional value/cost trade-off