[en] The rapid development of electric vehicles (EVs) increases the power demand, which causes an extra burden on the public grid increasing the load fluctuations, therefore, hindering the high penetration of EVs. A real-time rule-based algorithm for electric vehicle (EV) charging stations empowered by a DC microgrid is proposed to deal with the uncertainties of EV users' behaviour considering its arbitrary and random choices through the human-machine interface, meanwhile considering most of the users' choices. The simulation results obtained under MATLAB/Simulink verify the feasibility of the proposed management strategy that presents a good performance in terms of precise control. In addition, EV shedding and restoration optimization algorithms (SROA) for battery charging power can be used to meet user needs while maintaining EV charging station power balance, taking into consideration the intermittency of the photovoltaic (PV) source, the capacity limitation of the storage, and the power limitation of the public grid. The simulation results show that compared with rule-based algorithm, the proposed SROA respect the user's choice while reducing total charging time, increasing the full rate, and maximizing the available power utilization, which shows the feasibility and effectiveness of SROA. Furthermore, a PV based charging station for EVs can participate to solve some peak power problems. On the other hand, vehicle to grid (V2G) technology is designed and applied to provide ancillary services grid during the peak periods, considering the duality of EV battery 'load-source'. So, a dynamic searching peak and valley algorithm, based on energy management, is proposed for an EV charging station to mitigate the impact on the public grid, while reducing the energy cost of the public grid. Simulation results demonstrate the proposed searching peak and valley algorithm effectiveness, which can guarantee the balance of the public grid, meanwhile satisfy the charging demand of EV users, and most importantly, reduce the public grid energy cost. (author)

[en] Preliminary results of the measurement of the cosmic ray muon zenith angle distribution are obtained using scintillation counter hodoscopes. This method takes advantage of better angular resolution. The telescope array consists of two 4 by 4 scintillation counter hodoscopes formed by 256 telescope units. Data for ten angles can be obtained simultaneously. Data taking and processing is performed with an on-line microcomputer

[en] We proposed that much lower forward martensitic transformation temperature (M_s) and lower yield strength were responsible for lower improvement of shape memory effect (SME) at room temperature (RT) in Co-based alloys than that in Fe-Mn-based alloys by Si alloying. To prove our opinion, the SME and martensitic transformation were investigated in Co-xNi-6Si (x = 15, 20, 25 wt%) alloys with higher Si content. The results confirmed that the Si addition could significantly improve the SME of Co-Ni-based alloys after adjusting the M_s temperature to around RT. The Co-20Ni-6Si alloy with M_s temperature close to RT showed the highest shape recovery of 80% after bent by 2.7%. This value was much higher than the ones in the Co-15Ni-6Si and Co-25Ni-6Si alloys whose M_s temperatures were much far from RT. The reduction in the M_s temperature by the Si addition augmented with increasing the Ni content.

[en] The (e, 2e) triple differential cross sections (TDCSs) of Ar (3s) are calculated by using distorted-wave Born approximation under coplanar asymmetric geometry. The incident electron energy is 113.5 eV, and the scattering electron angle θ₁ is −15°. The ejected electron energy is set at 10 eV, 7.5 eV, 5 eV, and 2 eV, respectively. The polarization effects have been discussed and the polarization potential V_pol changing from a second-order to a fourth-order term has been analyzed. Our calculated TDCSs have been compared with reported experimental and theoretical results, and the calculated TDCSs of polarization potential up to the fourth order could give a good fit with experimental results in the binary region, but fail to predict the correct recoil-to-binary ratio in most cases. (atomic and molecular physics)

[en] We have previously developed an online adaptive replanning technique to rapidly adapt the original plan according to daily CT. This paper reports the quality assurance (QA) developments in its clinical implementation for prostate cancer patients. A series of pre-clinical validation tests were carried out to verify the overall accuracy and consistency of the online replanning procedure. These tests include (a) phantom measurements of 22 individual patient adaptive plans to verify their accuracy and deliverability and (b) efficiency and applicability of the online replanning process. A four-step QA procedure was established to ensure the safe and accurate delivery of an adaptive plan, including (1) offline phantom measurement of the original plan, (2) online independent monitor unit (MU) calculation for a redundancy check, (3) online verification of plan-data transfer using an in-house software and (4) offline validation of actually delivered beam parameters. The pre-clinical validations demonstrate that the newly implemented online replanning technique is dosimetrically accurate and practically efficient. The four-step QA procedure is capable of identifying possible errors in the process of online adaptive radiotherapy and to ensure the safe and accurate delivery of the adaptive plans. Based on the success of this work, the online replanning technique has been used in the clinic to correct for interfractional changes during the prostate radiation therapy.

[en] Highlights: • Conjugate heat transfer analyses were performed for a film-cooled vane to reveal the effects of swirl and hot streak. • Swirl worsens the attachment of film coolant and its effects are susceptible to swirl orientations and positions. • Negative swirl aligned to vane is preferred for reducing heat load of vane leading edge. • Heat transfer coefficient on suction side is elevated due to the effect of transportation of swirl. Conjugate heat transfer (CHT) analyses were conducted on the film-cooled first stage vane of GE-E³ engine to reveal the influences of inlet swirl and hot streak (HS) on vane film cooling. Two cases with only HS and four cases considering with combined HS and swirl were studied, including the effects of HS/swirl to vane clocking positions (HS/swirl aligned to passage or vane) and swirl orientations (positive/negative). The results indicate that the variations of incidence angle combined with effects of radial transportation of the swirl vortex worsen the film coolant attachment, decrease the film cooling efficiency and increase the heat load onto vane surface. However, for film holes with radial angles toward the outer endwall, negative incidence near hub endwall is beneficial to the leading edge film coolant attachment. Therefore, a negative swirl aligned to the vane leads to lowering the temperature at the leading edge and the pressure side than the other three cases with combined swirl and HS. Heat transfer coefficient (HTC) on the suction surface (SS) is increased due to upwash and downwash of boundary layer fluids caused by swirl. The temperature on SS is therefore increased because the heat energy transferred from fluid to solid is increased.

[en] Highlights: • Low temperature processed ZnO based single & mixed organic cation perovskite device. • 37% higher PCE in mixed cation perovskite solar cells (PSCs) than single cation ones. • Mixed cation PSCs exhibit significantly reduced photocurrent hysteresis. • Mixed cation PSCs demonstrate three fold higher device stability than single cation PSCs. • Electronic properties are analyzed using Electrochemical Impedance Spectroscopy. - Abstract: The present work reports a comparative study between single and mixed organic cation based MAPbI₃ and MA_0.6FA_0.4PbI₃ perovskite devices fabricated in conjunction with low temperature processed (<150 °C) ZnO electron transport layers. MA_0.6FA_0.4PbI₃ perovskite devices demonstrate 37% higher power conversion efficiency compared to MAPbI₃ perovskite devices developed on the ZnO ETL. In addition, MA_0.6FA_0.4PbI₃ devices exhibit very low photocurrent hysteresis and they are three-fold more stable than conventional MAPbI₃ PSCs (perovskite solar cells). An in-depth analysis on the charge transport properties in both fresh and aged devices has been carried out using electrochemical impedance spectroscopy analysis to comprehend the enhanced device stability of the mixed perovskite devices developed on the ZnO ETL. The study also investigates into the interfacial charge transfer characteristics associated with the ZnO/mixed organic cation perovskite interface and concomitant influence on the inherent electronic properties.

[en] Highlights: • Effect of pure CsI ETL in PTB7:PC₇₁BM polymer solar cell is studied. • CsI/ZnO bi-layer ETL is incorporated instead of CsI or ZnO ETL. • CsI layer modifies energy level alignment at ITO/ZnO interface. • New ETL improves both device efficiency and UVO stability. - Abstract: Polymer solar cells (PSCs) have gained immense research interest in the recent years predominantly due to low-cost, solution process-ability, and facile device fabrication. However, achieving high stability without compromising the power conversion efficiency (PCE) serves to be an important trade-off for commercialization. In line with this, we demonstrate the significance of incorporating a CsI/ZnO bilayer as electron transport layer (ETL) in the bulk heterojunction PSCs employing low band gap polymer (PTB7) and fullerene (PC₇₁BM) as the photo-active layer. The devices with CsI/ZnO interlayer exhibited substantial enhancement of 800% and 12% in PCE when compared to the devices with pristine CsI and pristine ZnO as ETL, respectively. Furthermore, the UV and UV-ozone induced degradation studies revealed that the devices incorporating CsI/ZnO bilayer possess excellent decomposition stability (∼23% higher) over the devices with pristine ZnO counterparts. The incorporation of CsI between ITO and ZnO was found to favorably modify the energy-level alignment at the interface, contributing to the charge collection efficiency as well as protecting the adjacent light absorbing polymer layers from degradation. The mechanism behind the improvement in PCE and stability is analyzed using the electrochemical impedance spectroscopy and dark I–V characteristics.

[en] Purpose: Intensity-modulated radiation therapy (IMRT) is a promising treatment modality for patients with head and neck cancer (HNC). The dose distributions from IMRT are static and, thus, are unable to account for variations and/or uncertainties in the relationship between the patient (region being treated) and the beam. Organ motion comprises one such source of this uncertainty, introduced by physiological variation in the position, size, and shape of organs during treatment. In the head and neck, the predominant source of this variation arises from deglutition (swallowing). The purpose of this study was to investigate whether cinematographic MRI (cine MRI) could be used to determine asymmetric (nonuniform) internal margin (IM) components of tumor planning target volumes based on the actual deglutition-induced tumor displacement. Methods: Five head and neck cancer patients were set up in treatment position on a 3 T MRI scanner. Two time series of single-slice, sagittal, cine images were acquired using a 2D FLASH sequence. The first time series was a 12.8 min scan designed to capture the frequency and duration of deglutition in the treatment position. The second time series was a short, 15 s scan designed to capture the displacement of deglutition in the treatment position. Deglutition frequency and mean swallow duration were estimated from the long time series acquisition. Swallowing and resting (nonswallowing) events were identified on the short time series acquisition and displacement was estimated based on contours of gross tumor volume (GTV) generated at each time point of a particular event. A simple linear relationship was derived to estimate 1D asymmetric IMs in the presence of resting- and deglutition-induced displacement. Results: Deglutition was nonperiodic, with frequency and duration ranging from 2.89-24.18 mHz and from 3.86 to 6.10 s, respectively. The deglutition frequency and mean duration were found to vary among patients. Deglutition-induced maximal GTV displacements ranged from 0.00 to 28.36 mm with mean and standard deviation of 4.72±3.18, 3.70±2.81, 2.75±5.24, and 10.40±10.76 mm in the A, P, I, and S directions, respectively. Resting-induced maximal GTV displacement ranged from 0.00 to 5.59 mm with mean and standard deviation of 3.01±1.80, 1.25±1.10, 3.23+2.20, and 2.47±1.11 mm in the A, P, I, and S directions, respectively. For both resting and swallowing states, displacement along the S-I direction dominated displacement along the A-P direction. The calculated IMs were dependent on deglutition frequency, ranging from 3.28-4.37 mm for the lowest deglutition frequency patient to 3.76-6.43 mm for the highest deglutition frequency patient. A statistically significant difference was detected between IMs calculated for P and S directions (p=0.0018). Conclusions: Cine MRI is able to capture tumor motion during deglutition. Swallowing events can be demarcated by MR signal intensity changes caused by anatomy containing fully relaxed spins that move medially into the imaging plane during deglutition. Deglutition is nonperiodic and results in dynamic changes in the tumor position. Deglutition-induced displacements are larger and more variable than resting displacements. The nonzero mean maximum resting displacement indicates that some tumor motion occurs even when the patient is not swallowing. Asymmetric IMs, derived from deglutition frequency, duration, and directional displacement, should be employed to account for tumor motion in HNC RT.

[en] In this article, we attempt to demonstrate a way of tackling one of the biggest challenges in the path of commercialization of organic solar cells, the initial photo-degradation of the cells known as “burn-in”. The “burn-in” phenomenon is most prominent during the first few hours of device operation under illumination and responsible for losing 25% or more fraction of the initial efficiency. To address this major issue, we have studied photo degradation of inverted organic solar cells with plain Zinc Oxide (ZnO) and Aluminum doped ZnO (AZO) as an electron transport layer over a short time period of 5 h during which the degradation is most severe. The study has been done on two different device structures containing both crystalline and amorphous polymers (Poly(3-hexylthiophene-2,5-diyl) and Poly({4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl}{3-fluoro-2-[(2 ethylhexyl)carbonyl]thieno[3,4-b]thiophenediyl}), respectively). Application of an AZO layer as the electron transport layer resolves the issue of photo-degradation in both cases, regardless of the polymer used in the active layer. AZO layer is found to provide less charge accumulation and better charge extraction at cathode/active layer interface. Mott-Schottky analysis shows modification of cathode interfacial layer work function and enhancement of open-circuit voltage due to the introduction of doped ZnO as electron transport layer. The exaltation persists even after the ageing of the devices. The devices with AZO layer retain their initial efficiency (almost 100%) even after photo-degradation while the device with pristine ZnO layer loses up to 60% of the initial efficiency. - Highlights: • Burn-in loss is one of the major degradation issues in organic solar cells. • Optimum doping of ZnO with Aluminum (AZO) reduces the burn-in loss significantly. • The optimum amount of Aluminum doping varies with respect to the polymer used. • Near 100% PCE is retained in AZO devices after continuous illumination of 5 h. • Impedance and Mott-Schottky analysis revealed underlying charge transport properties.