Olive oil waste treatment: a comparative and critical presentation of methods, advantages & disadvantages

Since olive oil industries were considered responsible for a great amount of pollution there has been a strong need for optimization of olive oil waste treatment systems. The currently employed systems are numerous and fall in the following large categories; bioremediation (ex-situ, in-situ), thermal processes (incineration, pyrolysis, gasification), evaporation, membrance processes, electrolysis, ozonation, digestion, coagulation/flocculation/precipitation, and distillation. Both advantages and disadvantages in conjunction with respective methodology and explicit flow diagrams were presented per waste treatment method. Furthermore, most recent studies were reported and more than twenty-five figures showing mainly the effectiveness of the current waste treatment methods versus time or temperature were displayed. The comparative presentation of the various olive oil waste treatment methodologies showed that though bioremediation stands for the most enviromentally friendly technique, its required longer treatment time in conjuction with its weakness to deal with elemental contaminants makes imperative the employment of a second alternative technique which could either be a membrance process (low energy cost, reliability, reduced capital cost) or a coagulation/flocculation method because of its low cost and high effectiveness. Biogas production appears to be another promising and energy effective waste treatment method. On the other hand, methods like distillation and ozonation (high cost) and electrolysis (experimental level) are unlikely to dominate this field unless their high cost is substantially reduced in the near future.     

Rain attenuation problems affecting the performance of microwave communication systems

Rain attenuation is considered to be a dominant factor affecting the reliability of both terrestrial and earth-to-satellite paths operating at frequencies above 10 GHz. The subject of the present paper is the development of some efficient models for the prediction of the operational characteristics (such as the path enlargement factor, accumulation thermal noise, site diversity improvement) of microwave systems operating at these frequencies. The numerical results taken from the present models have been compared with available experimental data from operated links in USA, Europe, Japan and the agreement has been found to be quite encouraging.     

Rate-controlled constrained equilibrium: Formulation and application to nonpremixed laminar flames

Rate-controlled constrained equilibrium provides a sound framework for deriving and testing low-dimensional models of combustion chemistry, yet its application so far has been limited. The purpose of this paper is twofold: to propose a formulation of RCCE as a differential-algebraic problem and show how existing formulations such as the constraint potentials can be derived from it, and to demonstrate how combustion problems involving flow, such as nonpremixed laminar flames, can be solved with RCCE. A 9-constraint set is employed to reduce a 63-species detailed mechanism for CH₄-air combustion and is found to be sufficient for fairly accurate predictions of both ignition in a homogeneous reactor and the structure of nonpremixed laminar flames for a variety of strain rates, while the main features of the latter can also be reproduced with a 7-constraint subset.     

Charge-coupled device spectrograph for direct solar irradiance and sky radiance measurements

The characterization of a charged-coupled device (CCD) spectrograph developed at the Laboratory of Atmospheric Physics, Thessaloniki is presented. The absolute sensitivity of the instrument for direct irradiance and sky radiance measurements was determined, respectively, with an uncertainty of 4.4% and 6.6% in the UV-B, and 3% and 6% in the UV-A, visible and near-infrared (NIR) wavelength ranges. The overall uncertainty associated with the direct irradiance and the sky radiance measurements is, respectively, of the order of 5% and 7% in the UV-B, increasing to 10% for low signals [e.g., at solar zenith angles (SZAs) larger than 70 degrees ], and 4% and 6% in the UV-A, visible, and NIR. Direct solar spectral irradiance measurements from an independently calibrated spectroradiometer (Bentham DTM 300) were compared with the corresponding CCD measurements. Their agreement in the wavelength range of 310-500nm is within 0.5% +/- 1.1% (for SZA between 20 degrees and 70 degrees ). Aerosol optical depth (AOD) derived by the two instruments using direct Sun spectra and by a collocated Cimel sunphotometer [Aerosol Robotic network (AERONET)] agree to within 0.02 +/- 0.02 in the range of 315-870 nm. Significant correlation coefficients with a maximum of 0.99 in the range of 340-360 nm and a minimum of 0.90 at 870 nm were found between synchronous AOD measurements with the Bentham and the Cimel instruments.     

Controlled Fab installation onto polymeric micelle nanoparticles for tuned bioactivity

Abstract

Antibodies and antigen-binding fragments (Fabs) can be used to modify the surface of nanoparticles for enhanced target binding. In our previous work, site-specific conjugation of Fabs to polymeric micelles using conventional methods was limited to approximately 30% efficiency, possibly due to steric hindrance related to macromolecular reactants. Here, we report a new method that enables conjugation of Fabs onto a micelle surface in a controlled manner with up to quantitative conversion of nanoparticle reactive groups. Variation of (i) PEG spacer length in a heterofunctionalized cross-linker and (ii) Fab/polymer feed ratios resulted in production of nanoparticles with a range of Fab densities on the surface up to the theoretical maximum value. The biological impact of variable Fab density was evaluated in vitro with respect to cell uptake and cytotoxicity of a drug-loaded (SN38) targeted polymeric micelle bearing anti-EphA2 Fabs. Fab conjugation increased cell uptake and potency compared with non-targeted micelles, although a Fab density of 60% resulted in decreased uptake and potency of the targeted micelles. Altogether, our findings demonstrate that conjugation strategies can be optimized to allow control of Fab density on the surface of nanoparticles and also that Fab density may need to be optimized for a given cell-surface target to achieve the highest bioactivity.     

Characteristics of set type yoghurt made from caprine or ovine milk and mixtures of the two

Rheological, physico‐chemical and organoleptic studies were made on five types of yoghurt originally from pure caprine milks of an Alpine breed and local breeds, pure ovine milk of the Lacaune breed, and two mixtures containing 50% caprine milk from an Alpine breed + 50% ovine milk of the Lacaune breed and 70% caprine milk of local breeds + 30% ovine milk of the Lacaune breed. Comparison of the yoghurts showed that it was possible to produce yoghurt of good quality from the last four types of milk. In contrast, pure caprine milk from an Alpine breed was not suitable for the production of yoghurt as this milk is low in dry matter and the yoghurt that was produced had the lowest firmness and significantly inferior organoleptic characteristics. Yoghurts prepared from mixtures of 50% caprine milk of an Alpine breed + 50% ovine milk of the Lacaune breed, and 70% caprine milk of local breeds + 30% ovine milk of the Lacaune breed, were of good quality, with similar consistency, rheological and organoleptic characteristics.     

How the structural deviations on the backbone of conjugated polymers influence their optoelectronic properties and photovoltaic performance

The design of novel conjugated polymers with appropriate frontier orbital energy levels, low band gap (LBG) and suitable carrier transport properties are needed to improve the power conversion efficiency (PCE) of organic photovoltaic devices. In this review, a detailed structure-property relationship study is presented, by identifying those chemical entities in the backbone of conjugated polymers that are responsible for the modification of optoelectronic properties towards high photovoltaic performance.