In this study, the effect of cell temperature on the photovoltaic parameters of mono-crystalline silicon solar cell is undertaken. The experiment was carried out employing solar cell simulator with ...varying cell temperature in the range 25-60 êC at constant light intensities 215-515 W/m2. The results show that cell temperature has a significant effect on the photovoltaic parameters and it controls the quality and performance of the solar cell. The open circuit voltage, maximum power, fill factor and efficiency are found to be decreased with cell temperature. The reverse saturation current increases with cell temperature and a slight increment is observed in the short circuit current. The temperature coefficient of the open-circuit voltage, fill factor and maximum output power is found to be negative while positive for the short circuit current. The relative change study of photovoltaic parameters with temperature is also undertaken. The relative changes are found from -0.0022/êC to -0.0025/êC, 0.002/êC, -0.0013/êC and -0.002/êC for open circuit voltage, short circuit current, fill factor and maximum output power respectively. The results are in good agreement with the available literature.
Abstract Intermediate-mass black holes (IMBHs) are believed to be the missing link between the supermassive black holes (BHs) found at the centers of massive galaxies and BHs formed through stellar ...core collapse. One of the proposed mechanisms for their formation is a collisional runaway process in high-density young star clusters, where an unusually massive object forms through repeated stellar collisions and mergers, eventually collapsing to form an IMBH. This seed IMBH could then grow further through binary mergers with other stellar-mass BHs. Here we investigate the gravitational-wave (GW) signals produced during these later IMBH–BH mergers. We use a state-of-the-art semi-analytic approach to study the stellar dynamics and to characterize the rates and properties of IMBH–BH mergers. We also study the prospects for detection of these mergers by current and future GW observatories, both space-based (LISA) and ground-based (LIGO Voyager, Einstein Telescope, and Cosmic Explorer). We find that most of the merger signals could be detected, with some of them being multiband sources. Therefore, GWs represent a unique tool to test the collisional runaway scenario and to constrain the population of dynamically assembled IMBHs.
The temperature induced optical and structural properties of thermally evaporated CdTe thin films have been investigated in the present work. The deposited films were annealed at 150 °C, 250 °C and ...350 °C in air atmosphere and subjected to the UV–Vis spectrophotometer, XRD, source meter, SEM and EDAX for optical, structural, electrical, morphological and elemental analysis. The films are found to be crystallized in cubic zinc-blende structure with preferred orientation (111) and crystallinity is improved with annealing temperature. The optical absorbance is found to increase with annealing while energy band gap is observed to decrease. Different optical parameters like extinction coefficient, refractive index, relative density, dielectric constant and energy loss functions have been calculated using dielectric theory, Swanepoel model and Herve-Vandamme model. The surface morphology shows that the films are homogeneous, smooth and free from defects. The current-voltage characteristics show that the electrical conductivity is increased with annealing and resistivity is observed to decrease. The results confirm that films annealed at 350 °C may be used as absorber layer to fabricate CdTe/CdS solar cell devices.
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•Enhancement of physical properties of vacuum evaporated CdTe thin films has been investigated.•Structural analysis reveals that the films are crystallized in cubic zinc-blende structure.•Optical band gap is found in the range 1.57–1.87 eV and observed to decrease with annealing temperature.•Electrical resistivity is observed to decrease with annealing.•Morphology studies show that the films are uniform, homogeneous and free from defects.
The physical properties of electron beam evaporated and chlorine-passivated CdTe thin films are investigated and the influence of NH4Cl treatment on these properties is studied. X-ray diffraction, ...UV–Vis spectrophotometry, energy-dispersive spectroscopy, atomic force microscopy, and a source meter were used to investigate the physical properties, which were optimized by varying the temperature of the treatment after NH4Cl activation. Structural analysis reveals that the crystallinity is increased at lower annealing temperature while a partial phase transition and oxidation are observed at higher annealing temperature. The absorbance is high in the visible region, and a red shift is observed at higher wavelength, while the direct bandgap is tuned by chlorine activation. The deposition of thin films and chlorine treatment were confirmed by elemental analysis. Surface topographical study reveals that the average roughness is increased with an annealing temperature up to 320 °C, while the I-V characteristics indicated ohmic nature of the contacts. The optimized results show that the NH4Cl-treated CdTe films annealed at 320 °C may be applicable as an absorber layer in solar cells.
The graphical representation of processes like film fabrication, NH4Cl heat treatment and optimized physical properties is shown in Fig. 1. Display omitted
•Physical properties of NH4Cl-treated CdTe thin films are studied.•The films are polycrystalline, having cubic and hexagonal phases.•Absorbance is increased and the bandgap changes with NH4Cl treatment.•Surface roughness and grain size are maximum for NH4Cl-treated CdTe thin films annealed at 320 °C.•NH4Cl-treated CdTe thin films may be used as an absorber layer.
The energy demand of the world is rapidly increasing and to cater this, there is a need to explore new renewable energy resources. CdSe thin film solar cells may be promising alternative to the CdTe ...solar cells which are extensively studied and used in solar cell technology. The pre/post deposition chlorine based treatments (viz. CdCl2, MgCl2, NH4Cl) are the important steps to enhance the performance of Cd-based thin film solar cells. Therefore, a study on MgCl2 activation treatment to CdSe thin films for solar cell applications as absorber layer is undertaken. Different physical properties of e-beam evaporated CdSe films (thickness 550 nm) grown on glass and ITO substrates are investigated and found to be strongly dependent on the post-chlorine treatment. The films have cubic zinc-blende structure and phase transformation from cubic (111) to hexagonal (002) is achieved with the MgCl2 treatment while the optical band gap is reduced. I-V characteristics reveal the linear relation between voltage and current as well as the surface roughness is varied with treatment and improved homogeneity. The deposition of CdSe thin films is confirmed by elemental analysis where Cd and Se were found to be rich with treatment. The investigated results suggest that CdSe thin films treated by MgCl2 and annealed at 320 °C may be a viable alternative absorber layer to the Cd-based solar cells.
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•First ever study on post-MgCl2 treatment to the CdSe thin films is carried out.•Films show phase transition from cubic to hexagonal at higher annealing.•Absorbance is increased upto 70% and band gap is decreased with MgCl2 treatment.•Surface roughness is found maiximum for films annealed at 320 °C.•MgCl2 treated CdSe thin films at 320 °C may be used as an absorber layer.
This paper presents a study on impact of temperature on the performance of series and parallel connected mono-crystalline silicon (mono-Si) solar cell employing solar simulator. The experiment was ...carried out at constant light intensity 550 W/m2with cell temperature in the range 25-60 oC for single, series and parallel connected mono-Si solar cells. The performance parameters like open circuit voltage, maximum power, fill factor and efficiency are found to decrease with cell temperature while the short circuit current is observed to increase. The experimental results reveal that silicon solar cells connected in series and parallel combinations follow the Kirchhoff's laws and the temperature has a significant effect on the performance parameters of solar cell.
Aims
The aim of this study was to use a sensitive method to screen and quantify 57 Vibrionaceae strains for the production of acyl‐homoserine lactones (AHLs) and map the resulting AHL profiles onto a ...host phylogeny.
Methods and Results
We used a high‐performance liquid chromatography–tandem mass spectrometry (HPLC‐MS/MS) protocol to measure AHLs in spent media after bacterial growth. First, the presence/absence of AHLs (qualitative analysis) was measured to choose internal standard for subsequent quantitative AHL measurements. We screened 57 strains from three genera (Aliivibrio, Photobacterium and Vibrio) of the same family (i.e. Vibrionaceae). Our results show that about half of the isolates produced multiple AHLs, typically at 25–5000 nmol l−1.
Conclusions
This work shows that production of AHL quorum sensing signals is found widespread among Vibrionaceae bacteria and that closely related strains typically produce similar AHL profiles.
Significance and Impact of the Study
The AHL detection protocol presented in this study can be applied to a broad range of bacterial samples and may contribute to a wider mapping of AHL production in bacteria, for example, in clinically relevant strains.
Various facts demonstrated that UVB is harmful to organisms. Sunscreen compounds are usually used to prevent the excessive damage caused by UVB. However, certain photosynthetic organisms have evolved ...mechanisms to counteract the toxicity of ultraviolet radiation by synthesizing UV screening compounds such as mycosporine-like amino acids (MAAs). MAAs provide UV protection to primary and secondary consumers through food chain and to non-biological materials by photostabilizing action. Information related to the ecological consequence of MAAs and their spatial distribution from a wide range of organisms is accumulating. Hence, our studies seek a potent class of natural sun protective compounds to understand their relationship with environment and to develop a protocol for large-scale industrial production of these compounds so that they can find application as UV-protecting cosmetics.
Background
We tested the hypothesis that specific molecular sensitization patterns correlate with the clinical data/manifestation in a European peanut‐allergic population characterized under a common ...protocol.
Methods
Sixty‐eight peanut‐allergic subjects and 82 tolerant controls from 11 European countries were included. Allergy to peanut and lowest symptom‐eliciting dose was established by double‐blind placebo‐controlled food challenge in all but anaphylactic subjects. Information of early or late (before or after 14 years of age) onset of peanut allergy was obtained from standardized questionnaires. IgE to peanut allergens rAra h 1–3, 6, 8–9, profilin and CCD was determined using ImmunoCAP.
Results
Seventy‐eight percent of peanut allergics were sensitized to peanut extract and 90% to at least one peanut component. rAra h 2 was the sole major allergen for the peanut‐allergic population. Geographical differences were observed for rAra h 8 and rAra h 9, which were major allergens for central/western and southern Europeans, respectively. Sensitization to rAra h 1 and 2 was exclusively observed in early‐onset peanut allergy. Peanut‐tolerant subjects were frequently sensitized to rAra h 8 or 9 but not to storage proteins. Sensitization to Ara h 2 ≥ 1.0 kUA/l conferred a 97% probability for a systemic reaction (P = 0.0002). Logistic regression revealed a significant influence of peanut extract sensitization and region on the occurrence of systemic reactions (P = 0.0185 and P = 0.0436, respectively).
Conclusion
Sensitization to Ara h 1, 2 and 3 is usually acquired in childhood. IgE to Ara h 2 ≥ 1.0 kUA/l is significantly associated with the development of systemic reactions to peanut.
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