Improved outdoor monitoring of photovoltaic modules

The Centre for Renewable Energy Systems Technology (CREST) has been operating an outdoor measurement facility for testing photovoltaic (PV) modules since 1998. The facility is used to continuously measure the performance of a range of commercial and prototype modules, by scanning full I-V characteristics every ten minutes with synchronous measurements of ambient and module temperatures and broadband and spectral irradiance. The trend for increasingly high power PV modules and increased demand for channels has precipitated the next stage of development for the CREST system. A number of lessons have been learned from the past system which are indicated in this paper with a thorough system analysis, along with a description of the standard measurement cycle currently in operation. Then follows a full technical description of the new system, including the hardware design and software development

The LightSail 2 Controlled Solar Sailing Demonstration Mission

The LightSail 2 mission is the culmination of a decade-long program sponsored by The Planetary Society to advance solar sailing technology. The objective of LightSail 2 is to demonstrate controlled solar sailing in Earth orbit using a CubeSat platform. The LightSail 2 attitude is controlled using a single-axis momentum wheel and magnetic torque rods. During solar sailing operations, two 90 degree slews are performed each orbit to harness momentum from solar photons. Flight data show that LightSail 2 is successfully controlling its orientation relative to the Sun, and the controlled thrust from solar radiation pressure is measurably reducing the rate of orbital decay. The Planetary Society declared LightSail 2 mission success on July 31, 2019. This paper provides an overview of the LightSail 2 mission implementation, including the design of the flight system and flight software, and the pre-launch testing program. A summary of LightSail 2 mission operations is provided, including a description of the ground system. Solar sailing performance is presented, and anomalies encountered during the mission are discussed. The flight team continues to refine solar sailing performance and conduct on-orbit imaging for engineering purposes and to engage public interest. The LightSail program is entirely donor-funded, with over 50,000 contributors around the globe

Investigating the seasonal performance of amorphous silicon single- and multi-junction modules

The seasonal performance fluctuations observed in amorphous silicon solar cells are investigated. The dominant forces driving the increased efficiency in summer are identified, from long-term measurements, to be thermal annealing and spectral variations. A method for correcting for changes in the incident spectrum is applied in order to correct for the seasonal changes. In a second step, the fill factor is investigated in order to establish the magnitude of thermal annealing seen by these devices. The magnitude of each effect is investigated

Small-x QCD studies with CMS at the LHC

The capabilities of the CMS experiment to study the low-x parton structure and QCD evolution in the proton and the nucleus at LHC energies are presented through four different measurements, to be carried out in Pb-Pb at sqrt(s_NN) = 5.5 TeV: (i) the charged hadron rapidity density $dN_{ch}/d\eta$ and (ii) the ultraperipheral (photo)production of Upsilon; and in p-p at sqrt(s) = 14 TeV: (iii) inclusive forward jets and (iv) Mueller-Navelet dijets (separated by $Delta\eta\gtrsim$ 8).Comment: Quark Matter'06 Proceedings. To appear in J.Phys.

Impact of spectral effects on the electrical parameters of multijunction amorphous silicon cells

The influence of spectral variation on the efficiency of single-, double- and triple-junction amorphous silicon cells has been investigated. The average photon energy (APE) proves to be a useful device-independent environmental parameter for quantifying the average hue of incident spectra. Single-junction devices increase in efficiency as light becomes blue shifted, because more of the incident spectrum lies within the absorption window and less in the redlinfra-red tail; this is denoted the primary spectral effect. Double- and triple-junction devices also exhibit a secondary spectral effect due to mismatch between the device structure and the incident spectrum. These both reach a maximum efficiency, which drops off as light is red or blue shifted. The effect is more pronounced for triple-junction than double-junction devices, as mismatch between junctions is statistically more likely

Modeling and optimization of bistable composite laminates for piezoelectric actuation

Adaptive structures that allow large deformations under the application of a low and noncontinuous energy input are gaining increasing interest in the aerospace industry. One potential mechanism of realizing shape control is piezoelectric actuation of asymmetric composite laminates. This article presents an optimization study for the design of bistable laminates for a reversible snap-through enabled by two orthogonal piezoelectric layers. The formulation optimizes the load-carrying capability of the structure subject to deflection and actuation limits through a variation in ply orientations and laminate geometry. We find the problem to be multimodal with the multiple optima to be dependent on the loading and snap-through directions and the complex constraint boundary interactions. A reduction in the total actuation voltage is achieved through the simultaneous use of the positive and negative working ranges of the two piezoelectric layers. </jats:p

The PAX5 oncogene is expressed in N-type neuroblastoma cells and increases tumorigenicity of a S-type cell line

Neuroblastoma is a neural crest-derived neoplasm of infancy with poor outcome in patients with advanced disease. The oncogenic transcription factor PAX5 is an important developmental regulator and is implicated in the pathogenesis of several malignancies. Screening of neuroblastoma cell lines revealed PAX5 expression in a malignant subset of neuroblastoma cells, so-called ‘N-type' cells, but not in the more benign ‘S-type' neuroblastoma cells. PAX5 expression was also detected in small cell lung cancer, an aggressive tumor of neural crest origin. Based on this observation we hypothesized that there could be a relationship between PAX5 expression and the more malignant phenotype of N-type cells. Stable PAX5 expression was established in several clones of the S-type cell line CA-2E. A noticeable difference in morphology of these transfectants was observed and there was also a significant increase in the proliferation rate. Moreover, PAX5 expressing clones gained the ability to form colonies in a soft agar assay, a marker of tumorigenicity. Down-regulation of PAX5 in several N-type cell lines and one small cell lung cancer cell line utilizing small interfering RNA resulted in a significant decrease in growth rate. Taken together we propose PAX5 as an important factor for the maintenance of the proliferative and tumorigenic phenotype of neuroblastoma. Our data, together with a recent study on the role of PAX genes in cancer suggest that PAX5 and other PAX transcription factors might be valuable targets for cancer therap

Dystrophin Gene Mutation Location and the Risk of Cognitive Impairment in Duchenne Muscular Dystrophy

Contains fulltext : 88828.pdf (publisher's version ) (Open Access)BACKGROUND: A significant component of the variation in cognitive disability that is observed in Duchenne muscular dystrophy (DMD) is known to be under genetic regulation. In this study we report correlations between standardised measures of intelligence and mutational class, mutation size, mutation location and the involvement of dystrophin isoforms. METHODS AND RESULTS: Sixty two male subjects were recruited as part of a study of the cognitive spectrum in boys with DMD conducted at the Sydney Children's Hospital (SCH). All 62 children received neuropsychological testing from a single clinical psychologist and had a defined dystrophin gene (DMD) mutation; including DMD gene deletions, duplications and DNA point mutations. Full Scale Intelligence Quotients (FSIQ) in unrelated subjects with the same mutation were found to be highly correlated (r = 0.83, p = 0.0008), in contrast to results in previous publications. In 58 cases (94%) it was possible to definitively assign a mutation as affecting one or more dystrophin isoforms. A strong association between the risk of cognitive disability and the involvement of groups of DMD isoforms was found. In particular, improvements in the correlation of FSIQ with mutation location were identified when a new classification system for mutations affecting the Dp140 isoform was implemented. SIGNIFICANCE: These data represent one of the largest studies of FSIQ and mutational data in DMD patients and is among the first to report on a DMD cohort which has had both comprehensive mutational analysis and FSIQ testing through a single referral centre. The correlation between FSIQ results with the location of the dystrophin gene mutation suggests that the risk of cognitive deficit is a result of the cumulative loss of central nervous system (CNS) expressed dystrophin isoforms, and that correct classification of isoform involvement results in improved estimates of risk

Characterization of hARD2, a processed hARD1 gene duplicate, encoding a human protein N-α-acetyltransferase

BACKGROUND: Protein acetylation is increasingly recognized as an important mechanism regulating a variety of cellular functions. Several human protein acetyltransferases have been characterized, most of them catalyzing ε-acetylation of histones and transcription factors. We recently described the human protein acetyltransferase hARD1 (human Arrest Defective 1). hARD1 interacts with NATH (N-Acetyl Transferase Human) forming a complex expressing protein N-terminal α-acetylation activity. RESULTS: We here describe a human protein, hARD2, with 81 % sequence identity to hARD1. The gene encoding hARD2 most likely originates from a eutherian mammal specific retrotransposition event. hARD2 mRNA and protein are expressed in several human cell lines. Immunoprecipitation experiments show that hARD2 protein potentially interacts with NATH, suggesting that hARD2-NATH complexes may be responsible for protein N-α-acetylation in human cells. In NB4 cells undergoing retinoic acid mediated differentiation, the level of endogenous hARD1 and NATH protein decreases while the level of hARD2 protein is stable. CONCLUSION: A human protein N-α-acetyltransferase is herein described. ARD2 potentially complements the functions of ARD1, adding more flexibility and complexity to protein N-α-acetylation in human cells as compared to lower organisms which only have one ARD