The tilted ferroelectric SmC* phase of three structurally different series having three aromatic rings in the core structure connected by ester groups with different end alkyl chain lengths, all of which are derived from lactic acid, have been observed by broadband dielectric spectroscopy. Introduction of structural variations within the liquid crystalline compounds has led to the formation of chiral nematic N*, or the paraelectric orthogonal SmA* phase at higher temperatures. The dielectric spectra strongly depend both on the temperature as well as the specific molecular structure of the self-assembling compounds possessing the ferroelectric polar order. The results reveal a strong Goldstone mode in the ferroelectric SmC* phase with ~kHz relaxation frequency. In the SmC* phase, the real and imaginary parts of the complex permittivity increase up to certain temperature near the SmC*-N*/SmA* transition and then decrease with increasing temperature, perhaps due to the disruption of the molecular domains at the onset of the SmA*/N* phase transition. The dielectric strength attains a maximum value in the SmC* phase and then decreases near the SmA*/N* phase transition. The dielectric strength is also influenced by the lengths of the alkyl chain and the nature of the connecting unit of the constituent molecules. The relaxation time and the relaxation frequency are found to vary with the molecular structure of the studied ferroelectric compounds.
It is a well-known fact that automotive industries in every country are shifting towards electric vehicles (EVs) and in the days to come it is expected that the industry will become dominated by them, along with hybrid electric vehicles (HEVs). Unfortunately, the acceptance of EVs for mobility is affected by its poor range per charge. Thus, energy optimization and waste energy recuperation are currently in need. A promising method to recover energy that is lost during vehicle deceleration is regenerative braking, which extends the range of a vehicle by recovering the kinetic energy from braking and using it to recharge the battery. However, the intensity of the charging–discharging rate and the operating temperature of lithium–ion (Li–ion) batteries make them vulnerable to failure, making the rate of current delivered to the battery by regenerative braking a serious concern. Therefore, the focus of this review article is on how regenerative braking affects battery life and the precautions being taken to safeguard the battery against increased charge during regenerative braking. In this review paper, various research articles are referred to in order to examine how regenerative braking affects battery life. It is concluded that charging current obtained from long-term regenerative braking is the prominent factor in battery deterioration, regardless of the current intensity. Additionally, the rate of lithium plating is increased if the temperature and state of charge (SOC) are outside of the ideal range. By lowering the depth of discharge (DOD) and using shorter recharging times, higher levels of regenerative braking will extend a battery’s lifecycle even at high SOC and temperature.
Among the various advanced technological materials in the modern era; Liquid Crystals (LCs) have become one of the most important self-organizing molecular materials with their growing applications in the various field of science. The research associated with the Ferroelectric Liquid Crystals (FLCs) has become a subject of most intense area during the past few decades owing to their valuable intrinsic fundamental properties. At present their successful utilization in flat television screens, fast electro-optical switching devices etc. makes them extremely demandable in the commercial field. The fulfilment of this promise depends greatly on an improved understanding on the physical properties of the FLC materials. However, no single materials can exhibit all the desired properties for different applications. In order to fulfil all the requirements of the device manufacturer; preparation of suitable binary mixtures is one of the most simple and elegant way in the field of LC Research. Keeping this in mind some mixtures have prepared by using pure chiral FLC compounds and investigated in the light of the static dielectric permittivity (ε), dielectric anisotropy (∆ε), spontaneous polarization (Ps), response time (τ), torsional bulk viscosity () and dielectric spectroscopy. The temperature variation of Ps of the studied mixtures provides a preliminary idea about the order of the associated phase transitions namely SmA*-SmC* and N*-SmC*. The activation energy of all the mixtures have been determined from the best fitted Arrhenius plot. This assignment mainly contributes to the preparation and investigation of some smart multifunctional FLC mixtures aimed for optoelectronic and photonic applications.
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