Upper bounds for solar thermophotovoltaic efficiency

The main components of thermophotovoltaic (TPV) devices are the primary lens (or mirror), the absorber, the PV cell, and a photon recuperator system. A theory integrating all these components is used in this paper to analyse a particular type of TPV device (plane disk absorber and PV cell). The TPV efficiency is maximized by using three optimization parameters, namely absorber, PV cell temperatures, and cell voltage. Almost ideal operation conditions are envisaged and upper bounds are obtained for the TPV efficiency. They are strongly dependent on PV cell bandgap and radiation concentration. Preliminary results suggest the existence of an optimum solar radiation concentration ratio. The improvement in thermal design quality allows the usage of PV cells based on wide bandgap semiconductors.     

Deblurring by Matching

Restoration of the photographs damaged by the camera shake is a challenging task that manifested increasing attention in the recent period. Despite of the important progress of the blind deconvolution techniques, due to the ill-posed nature of the problem, the finest details of the kernel blur cannot be recovered entirely. Moreover, the additional constraints and prior assumptions make these approaches to be relative limited.
In this paper we introduce a novel technique that removes the undesired blur artifacts from photographs taken by hand-held digital cameras. Our approach is based on the observation that in general several consecutive photographs taken by the users share image regions that project the same scene content. Therefore, we took advantage of additional sharp photographs of the same scene. Based on several invariant local feature points, filtered from the given blurred/non-blurred images, our approach matches the keypoints and estimates the blur kernel using additional statistical constraints.
We also present a simple deconvolution technique that preserves edges while minimizing the ringing artifacts in the restored latent image. The experimental results prove that our technique is able to infer accurately the blur kernel while reducing significantly the artifacts of the spoilt images.     

Betulinic Acid in Complex with a Gamma-Cyclodextrin Derivative Decreases Proliferation and in Vivo Tumor Development of Non-Metastatic and Metastatic B164A5 Cells

Betulinic acid, a very promising anti-melanoma agent, has very low water solubility that causes low bioavailability. To overcome this inconvenience, a highly water-soluble cyclodextrin was used (octakis-[6-deoxy-6-(2-sulfanyl ethanesulfonic acid)]-γ-cyclodextrin). The complex was physico-chemically analyzed using differential scanning calorimetry (DSC), X-ray and scanning electron microscopy (SEM) methods and then in vitro tested for its antiproliferative activity by the MTT assay and by cell cycle analysis. Finally, the complex was tested in vivo using an animal model of murine melanoma developed in C57BL/6J mice, where it caused a reduction in tumor volume and weight. The study revealed the beneficial influence of betulinic acid inclusion into the cyclodextrin in terms of antiproliferative activity and in vivo tumor development.     

Osteonecrosis of the Jaws in Patients with Hereditary Thrombophilia/Hypofibrinolysis—From Pathophysiology to Therapeutic Implications

Osteonecrosis of the jaws (ONJ) usually has a clear etiology. Local infection or trauma, radiotherapy and drugs that disrupt the vascular supply or bone turnover in the jaws are its major contributors. The thrombotic occlusion of the bone’s venous outflow that occurs in individuals with hereditary thrombophilia and/or hypofibrinolysis has a less known impact on jaw health and healing capability. Our research provides the most comprehensive, up-to-date and systematized information on the prevalence and significance of hereditary thrombophilia and/or hypofibrinolysis states in ONJ. We found that hereditary prothrombotic abnormalities are common in patients with ONJ refractory to conventional medical and dental treatments. Thrombophilia traits usually coexist with hypofibrinolysis traits. We also found that frequently acquired prothrombotic abnormalities coexist with hereditary ones and enhance their negative effect on the bone. Therefore, we recommend a personalized therapeutic approach that addresses, in particular, the modifiable risk factors of ONJ. Patients will have clear benefits, as they will be relieved of persistent pain and repeated dental procedures.     

Concentration influences on recovery in a high gradient magneticseparation axial filter

The buildup differential equations for the case of a single wire in high gradient magnetic filtration (HGMF)-axial configuration taking into account the suspension concentration are solved. A new equation for the deposit contour surface at different moments and for different suspension concentrations are obtained. The existence of a particulate suspension concentration, for which the radial extension velocity of deposit is maximum, is evidenced. The recovery for an ordered ferromagnetic matrix is calculated. The influence of the solid particle concentration from suspension on the filtration efficiency is presented     

Biomass estimation of mixed forest landscape using a Fourier transform texture-based approach on very-high-resolution optical satellite imagery

Assessment of forest structure parameters via remote-sensing data offers the opportunity to examine stand parameters and to detect degradation and forest dynamics, such as above-ground biomass (AGB), at the landscape scale. While much attention has focused on spectrum-based and radar backscatter approaches for assessing forest biomass, texture-based approaches show strong promise. This work makes use of the novel Fourier transform textural ordination (FOTO) method, which involves the combination of 2D fast Fourier transform (FFT) and ordination through principal component analysis (PCA) for characterizing the structural and textural properties of vegetation. This technique presents the potential of Fourier transform approaches in estimating the different forest types, their stand structure, and biomass dynamics in the context of an oil palm–tropical forest landscape in Sabah, Malaysian Borneo. The method was applied to the recordings of very-high-resolution (VHR) Satellite Pour l’Observation de la Terre (SPOT) imagery of the study area. The technique proved useful in distinguishing between the forest types and developing individual biomass estimate models for various forest types. Results show that the FOTO method is able correctly to resolve high AGB values of various forest types. These findings are in agreement with the results based on ground measurements.     

Computing global and diffuse solar hourly irradiation on clear sky. Review and testing of 54 models

Fifty-four broad band models for computation of global and diffuse irradiance on horizontal surface are shortly presented and tested. The input data for these models consist of surface meteorological data, atmospheric column integrated data and data derived from satellite measurements. The testing procedure is performed for two meteorological stations in Romania (South-Eastern Europe). The testing procedure consists of forty-two stages intended to provide information about the sensitivity of the models to various sets of input data. There is no model to be ranked “the best” for all sets of input data. Very simple models as well as more complex models may belong to the category of “good models”. The best models for solar global radiation computation are, on equal-footing, ESRA3, Ineichen, METSTAT and REST2 (version 81). The second best models are, on equal-footing, Bird, CEM and Paulescu & Schlett. The best models for solar diffuse radiation computation are, on equal-footing, ASHRAE2005 and King. The second best model is MAC model. The best models for computation of both global and diffuse radiation are, on equal-footing, ASHRAE 1972, Biga, Ineichen and REST2 (version 81). The second best is Paulescu & Schlett model.     

Anorexic contribution to increased linoleate mobilization and oxidation in lymphoma-bearing mice

To test for a regulatory defect in adipose triacylglycerol (essential) fatty acid mobilization in lymphoma-bearing mice, free [1-¹⁴C]linoleic acid/mouse serum albumin was injectediv into lymphoma-bearing and control mice, adapted to a reversed light cycle, and studied in three dietary states in the dark period. Mean daily food intake decreased in mice with small and large tumor burdens. Plasma free fatty acid (FFA) oxidation rates, which approximate FFA mobilization rates, were estimated by multicompartmental analysis (CONSAM). Oxidation of linoleate to CO₂ was reduced significantly (85%) inad libitum fed as compared to briefly fasted control mice but not in fedvs. fasted mice with large or small tumor burdens. However, plasma FFA oxidation rates to CO₂ did not differ in briefly fasted tumor-bearing and pairfed control mice. When re-fed a 250-mg test meal, briefly fasted mice with small tumors suppressed plasma free linoleic acid oxidation, as did controls. During simulated night, mildly anorexic, tumor-bearing mice with small tumor burdens mobilized essential fatty acids much faster than controls. This could explain body fat loss. The abnormally rapid rates of FFA (free linoleic acid) mobilization at night probably result from anorexia rather than from inability of food to suppress fat mobilization.     

Verification of some very simple clear and cloudy sky models to evaluate global solar irradiance

Several very simple clear sky and cloudy sky global irradiance models were tested under the climate and latitudes of Romania (Eastern Europe). The very simple clear sky models do not require meteorological data while the very simple cloudy sky models need only data on the total cloud amount. Three slightly more complex cloudy sky models which use additional meteorological inputs were also tested. The mean absolute error of the very simple clear sky models varies between 7 and 14% in July and between 12 and 19% in January. The best model originates from Western Europe. The performance of the very simple cloudy sky models is comparable to that of the more complicated ones. This is the main conclusion of the paper. Generally, their root mean square error varies between 35 and 45% in close agreement with results from the literature. Twelve classes of daily average cloudiness were defined. The model accuracy is better for the first six classes (with smaller cloud amount) and worse for the other six classes.