Parallel soiling measurements for 4 mirror samples during outdoor exposure with TraCS

The upgraded version of the Tracking Cleanliness Sensor, the so-called TraCS4, which determines the realtime cleanliness and soiling rate of four mirror samples simultaneously is presented. Using this device, different materials can be intercompared at the site of interest which is the main advantage as the performance of anti-soiling-coatings is usually dependent on local weather conditions. A detailed uncertainty analysis of the TraCS4 device results in a cleanliness measurement uncertainty of about 0.019 cleanliness points. The uncertainty for the intercomparison of different materials is derived to be 0.012 cleanliness points. Exemplary soiling measurements with different anti-soiling and reference coatings at PSA are presented

SIGLEC1 (CD169): a marker of active neuroinflammation in the brain but not in the blood of multiple sclerosis patients

We aimed to evaluate SIGLEC1 (CD169) as a biomarker in multiple sclerosis (MS) and Neuromyelitis optica spectrum disorder (NMOSD) and to evaluate the presence of SIGLEC1(+) myeloid cells in demyelinating diseases. We performed flow cytometry-based measurements of SIGLEC1 expression on monocytes in 86 MS patients, 41 NMOSD patients and 31 healthy controls. Additionally, we histologically evaluated the presence of SIGLEC1(+) myeloid cells in acute and chronic MS brain lesions as well as other neurological diseases. We found elevated SIGLEC1 expression in 16/86 (18.6%) MS patients and 4/41 (9.8%) NMOSD patients. Almost all MS patients with high SIGLEC1 levels received exogenous interferon beta as an immunomodulatory treatment and only a small fraction of MS patients without interferon treatment had increased SIGLEC1 expression. In our cohort, SIGLEC1 expression on monocytes was-apart from those patients receiving interferon treatment-not significantly increased in patients with MS and NMOSD, nor were levels associated with more severe disease. SIGLEC1(+) myeloid cells were abundantly present in active MS lesions as well as in a range of acute infectious and malignant diseases of the central nervous system, but not chronic MS lesions. The presence of SIGLEC1(+) myeloid cells in brain lesions could be used to investigate the activity in an inflammatory CNS lesion

T-TraCS – An automated method to measure soiling losses at parabolic trough receiver tubes

Soiling of the envelope tubes of parabolic trough collectors can significantly reduce their transmittance and hence the overall collector efficiency. There are only a few methods to quantify soiling losses at absorber tubes of parabolic trough collectors. The existing methods are either laboratory based and cannot be applied automatically or they are personnel intense because they can only be used manually inside of operational solar fields. In this work we present a novel device called T-TraCS capable of automatically measuring the transmission of a sample glass during outdoor exposure with the current solar spectrum and imitating the movement of operational parabolic trough collectors. It can be used in resource assessment campaigns in order to better estimate future soiling losses at the tube level or it can be set up inside a solar field in order to measure the tube soiling losses in real time for CSP plant operation. Scattering simulations are presented that correct the measurement raw values of the T-TraCS and a spectrophotometer for their differences to the optics of a receiver tube. The validation with these final measurements shows good agreement with the reference spectrophotometer with a R2 of 0.996. The T-TraCS is therefore capable of automatically determining the soiling induced transmission losses with high accuracy

Investigation of soiling on mirror and glass samples with regard to power losses in CSP and PV technologies

This work undertakes a direct comparison of the influence of natural soiling on CSP and PV technologies by investigating outdoor exposed mirror and glass samples over a timespan of several weeks during summer in Évora, Portugal. Weather data as well as SEM and EDS analyses are used to support the investigations. It is shown that the measured relative soiling losses are approximately 8 to 14 times higher for CSP than for PV considering the same gravimetric density. Mean daily soiling rates are approximately 8 times higher (0.35%/d and 0.04%/d) for CSP and PV respectively. The results are used to create an optical model based on Mie scattering theory to successfully reproduce theses significant differences as well as the relation between soil gravimetric density and soiling losses for both technologies. The model is further extended to predict AOI responses for soiled PV modules. Calculations are made that recontextualize soiling loss measurements taken under normal AOI into an annual time frame with respect to the multiplicity of occurring AOI during the course of a year. Those calculations show that soiling loss measurements taken under normal AOI are not necessarily representative and suggestions are made to measure the soiling losses under specific angles with a corresponding weighting pattern based on the presented results

Works Council ‘Disaffection’ and Establishment Survivability

This paper investigates the association between a measure of works council heterogeneity and plant closings in Germany, 2006-2015. Two datasets are used to identify failed establishments, while institutional heterogeneity is captured by management perceptions of the role of the works council in managerial decision making and also by allowing for works council learning. The potential moderating role of sectoral collective bargaining is also examined. We report that works councils per se are not associated with plant closure. Rather, it is establishments with disaffected councils that display higher rates of closure. The latter result does not obtain where such establishments are covered by sectoral agreements; an outcome that is consistent with the literature on the mitigation of rent-seeking behavior, and one that also receives support from our finding that plants with dissonant councils are more likely than their consensual counterparts to transition into sectoral bargaining coverage. On the other hand, there is only limited evidence of works council learning

Comparative modeling of optical soiling losses for CSP and PV energy systems

Soiling is a challenge for both concentrating solar and photovoltaic technologies. Measurement procedures and efficiency sensitivities to soiling for the same surface particle density differ due to the different optical characteristics of both technologies. For this reason, soiling investigations performed at a site for one technology are not necessarily applicable to the other technology. Soiling measurements have been performed mostly under fixed or rarely occurring angles of incidence. In this study parallel measurements of soiling loss and particle mass density found on the main optical surfaces of concentrating solar power (CSP) and photovoltaic (PV) technologies are presented. The measurements are taken on samples of CSP second surface mirror and PV solar glass with consideration of the main optical characteristics of both technologies. Optical soiling losses are found to be higher by a factor of 8–14 in CSP for the same particle surface densities compared to PV. A Mie-based model is presented and validated, that converts the particle mass density and a set of other inputs into the optical soiling loss for either technology for normal angle of incidence and varying angles of incidence. This method facilitates the transfer of soiling loss data from one technology to another. The method can significantly increase the knowledge on soiling for both technologies as more measurement data is made accessible. Additionally, the soiling losses for different angles of incidence can be used to estimate more realistic annual loss parameters for the technologies in question and give recommendations for optimized incidence angles to be used in soiling measurements for both technologies