286 research outputs found
AgrivoltaicsâThe Perfect Fit for the Future of Organic Photovoltaics
Abstract This Essay presents a possible pathway for the advancement of organic photovoltaics toward broader commercial success and enlarged market size. This vision aims at broad scale applications in photovoltaic greenhouses and polytunnels, which harvest those portions of the solar spectrum that are not used or required by plants. Based on the assumptions of the ShockleyâQueisserâLimit, respectively detailed balance, and the additional postulation of using no absorption in the visible part of the AM 1.5G solar spectrum a power conversion efficiency of â17% is theoretically predicted. The suggestion is supported by the existence of a number of organic compounds, which already exhibit a good spectral compatibility with the typical photosynthetic action spectrum of chloroplasts. It is hoped that more suitable materials development shall be triggered and fertilized as a result of this Essay.A promising path is suggested for upscaling of organic photovoltaics (OPV) toward true mass application in the form of semiâtransparent OPV embedded in polytunnels or greenâhouses. Here their specific properties, that is, offering narrow band absorption in the infrared wavelength range can be used as game changer. imag
Success Factors in Secure Software Development of Cloud Applications in Germany: A Qualitative-explorative Expert Study
The use of cloud computing continues to increase in Germany, according to Germanyâs digital association. However, threats to information security stand in the way of a comprehensive acceptance and penetration of cloud computing. Secure software development is described in the standard ISO/IEC 27001, security control A.14.2 âSecurity in development and support processesâ and in the cloud related code of practice standard ISO/IEC 27017 in chapter 14.2 âSecurity in development and support processesâ. Secure software development has the potential to reduce vulnerabilities and thus increase the security level of applications. When implementing a secure software development process of cloud applications, the question for organizations is which factors have a positive influence on success, where success is defined as an increased security level of cloud applications. This paper contributes to answering the questions of (RQ1) what potential success factors exist in secure software development of cloud applications in Germany and (RQ2) what role does strategic and operational aspects play
Effects of Disorder on the Pressure-Induced Mott Transition in -BEDT-TTF)Cu[N(CN)]Cl
We present a study of the influence of disorder on the Mott metal-insulator
transition for the organic charge-transfer salt
-(BEDT-TTF)Cu[N(CN)]Cl. To this end, disorder was introduced
into the system in a controlled way by exposing the single crystals to x-ray
irradiation. The crystals were then fine-tuned across the Mott transition by
the application of continuously controllable He-gas pressure at low
temperatures. Measurements of the thermal expansion and resistance show that
the first-order character of the Mott transition prevails for low irradiation
doses achieved by irradiation times up to 100 h. For these crystals with a
moderate degree of disorder, we find a first-order transition line which ends
in a second-order critical endpoint, akin to the pristine crystals. Compared to
the latter, however, we observe a significant reduction of both, the critical
pressure and the critical temperature . This result is consistent
with the theoretically-predicted formation of a soft Coulomb gap in the
presence of strong correlations and small disorder. Furthermore, we
demonstrate, similar to the observation for the pristine sample, that the Mott
transition after 50 h of irradiation is accompanied by sizable lattice effects,
the critical behavior of which can be well described by mean-field theory. Our
results demonstrate that the character of the Mott transition remains
essentially unchanged at a low disorder level. However, after an irradiation
time of 150 h, no clear signatures of a discontinuous metal-insulator
transition could be revealed anymore. These results suggest that, above a
certain disorder level, the metal-insulator transition becomes a smeared
first-order transition with some residual hysteresis.Comment: 20 pages, 7 figures, appeared in the Special Issue "Advances in
Organic Conductors and Superconductors" of Crystal
Evidence for electronically-driven ferroelectricity in the family of strongly correlated dimerized BEDT-TTF molecular conductors
By applying measurements of the dielectric constants and relative length
changes to the dimerized molecular conductor
-(BEDT-TTF)Hg(SCN)Cl, we provide evidence for order-disorder
type electronic ferroelectricity which is driven by charge order within the
(BEDT-TTF) dimers and stabilized by a coupling to the anions. According to
our density functional theory calculations, this material is characterized by a
moderate strength of dimerization. This system thus bridges the gap between
strongly dimerized materials, often approximated as dimer-Mott systems at 1/2
filling, and non- or weakly dimerized systems at 1/4 filling exhibiting charge
order. Our results indicate that intra-dimer charge degrees of freedom are of
particular importance in correlated -(BEDT-TTF)X salts and can
create novel states, such as electronically-driven multiferroicity or
charge-order-induced quasi-1D spin liquids.Comment: 6 pages, 4 figures + Supplementary Information (8 pages, 8 figures
RHEBI Expression in Embryonic and Postnatal Mouse
Ras homolog enriched in brain (RHEB1) is a member within the superfamily of GTP-binding proteins encoded by the RAS oncogenes. RHEB1 is located at the crossroad of several important pathways including the insulin-signaling pathways and thus plays an important role in different physiological processes. To understand better the physiological relevance of RHEB1 protein, the expres- sion pattern of RHEB1 was analyzed in both embryonic (at E3.5âE16.5) and adult (1-month old) mice. RHEB1 immu- nostaining and X-gal staining were used for wild-type and Rheb1 gene trap mutant mice, respectively. These inde- pendent methods revealed similar RHEB1 expression pat- terns during both embryonic and postnatal developments. Ubiquitous uniform RHEB1/ÎČ-gal and/or RHEB1 expres- sion was seen in preimplantation embryos at E3.5 and post- implantation embryos up to E12.5. Between stages E13.5 and E16.5, RHEB1 expression levels became complex: In particular, strong expression was identified in neural tis- sues, including the neuroepithelial layer of the mesenceph- alon, telencephalon, and neural tube of CNS and dorsal root ganglia. In addition, strong expression was seen in certain peripheral tissues including heart, intestine, muscle, and urinary bladder. Postnatal mice have broad spatial RHEB1 expression in different regions of the cerebral cortex, sub- cortical regions (including hippocampus), olfactory bulb, medulla oblongata, and cerebellum (particularly in Purkinje cells). Significant RHEB1 expression was also viewed in internal organs including the heart, intestine, urinary blad- der, and muscle. Moreover, adult animals have complex tis- sue- and organ-specific RHEB1 expression patterns with different intensities observed throughout postnatal develop- ment. Its expression level is in general comparable in CNS and other organs of mouse. Thus, the expression pattern of RHEB1 suggests that it likely plays a ubiquitous role in the development of the early embryo with more tissue-specific roles in later development
RHEB1 Expression in Embryonic and Postnatal Mouse
Ras homolog enriched in brain (RHEB1) is a member within the superfamily of GTP-binding proteins encoded by the RAS oncogenes. RHEB1 is located at the crossroad of several important pathways including the insulin-signaling pathways and thus plays an important role in different physiological processes. To understand better the physiological relevance of RHEB1 protein, the expres-sion pattern of RHEB1 was analyzed in both embryonic (at E3.5âE16.5) and adult (1-month old) mice. RHEB1 immu-nostaining and X-gal staining were used for wild-type and Rheb1 gene trap mutant mice, respectively. These inde-pendent methods revealed similar RHEB1 expression pat-terns during both embryonic and postnatal developments. Ubiquitous uniform RHEB1/ÎČ-gal and/or RHEB1 expres-sion was seen in preimplantation embryos at E3.5 and post-implantation embryos up to E12.5. Between stages E13.5 and E16.5, RHEB1 expression levels became complex: In particular, strong expression was identified in neural tis-sues, including the neuroepithelial layer of the mesenceph-alon, telencephalon, and neural tube of CNS and dorsal root ganglia. In addition, strong expression was seen in certain peripheral tissues including heart, intestine, muscle, and urinary bladder. Postnatal mice have broad spatial RHEB1 expression in different regions of the cerebral cortex, sub-cortical regions (including hippocampus), olfactory bulb, medulla oblongata, and cerebellum (particularly in Purkinje cells). Significant RHEB1 expression was also viewed in internal organs including the heart, intestine, urinary blad-der, and muscle. Moreover, adult animals have complex tis-sue- and organ-specific RHEB1 expression patterns with different intensities observed throughout postnatal develop-ment. Its expression level is in general comparable in CNS and other organs of mouse. Thus, the expression pattern of RHEB1 suggests that it likely plays a ubiquitous role in the development of the early embryo with more tissue-specific roles in later development
Response to Christopher P. Muzzillo's Comments on âIntroduction of a Novel Figure of Merit for the Assessment of Transparent Conductive Electrodes in Photovoltaics: Exact and Approximate Formâ
Similarities and differences between figure of merits (FOMs) for the assessment of transparent conductive electrodes (TCEs) are discussed. This article is a response to C. P. Muzzillo's comment on the introduction of the novel FOM (the soâcalled exact FOM or Anand's FOM) and it deals with questions about how implicit and how exact the different approaches really are and whether specific application cases can be covered or not. While the exact FOM has been introduced to provide an upper limit of photovoltaic power conversion efficiency for the whole range of possible transmittance and sheet resistance values of transparent conductive oxides, Muzzillo's comment points out specific application cases, that have to be treated with more individual modeling. In this work, the authors adopt these application cases into the exact FOM to demonstrate its applicability. Furthermore, the FOM approximation given by Muzzillo is used and slightly refined, yielding an even better agreement with the exact FOM. In the end, it is concluded that both approaches are justified: Muzzillo's FOM for very practical applications and Anand's (exact) FOM for fundamental assessment. In this work, both approaches have been harmonized to yield an ultimate tool for the future development of TCEs for photovoltaics
Determination of the side-separated pulmonary right-toleft shunt volume
Background :With the present method of intrapulmonary right-to-left shunt volume calculation, no differentiation can be made between the shunt volume shares of the right and left lungs. For a better understanding of pathophysiological processes during thorax surgery with side-separated ventilation, a side-separated shunt volume determination would be useful. Materials and Methods : In 14 young female pigs, catheters were implanted into the left atrium after left thoracotomy. After transient clamping of the ipsilateral pulmonary veins, pulmonary venous blood was selectively obtained from the right lung. Cardiac output (CO) and side-separated pulmonary perfusion were determined with flowprobes at the pulmonary trunk and the left pulmonary artery. The shunt volumes were determined before and after thoracotomy during two-lung ventilation (Two-LV), after one-lung (right) ventilation (One-LV) with a continuous positive airway pressure (CPAP) of +7.5, +5.0 cm H2O, and under atelectasis of the non-dependent left lung (NDL). Results : After thoracotomy in lateral decubitus position and Two-LV, the shunt volumes of the two lungs differ. The right lung holds the major share (11.0±1.7%CO) [mean±SD]. The share of the left NDL is only 3.3±1.4. Under One-LV (right) and CPAP in the NDL, the total pulmonary shunt volume rises. This is caused by the increase in the NDL shunt volume share to 8.8±5.2 under CPAP +7.5 (p<0.05) and to 9.7±2.5 under CPAP +5.0 (p<0.05). Conclusions : The new intraoperative method of side-separated arterial blood gas analysis in conjunction with side-separated perfusion measurement makes side- separated rightto- left shunt volume determination possible and may lead to interesting new pathophysiological insights
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