Solar hybrid photo-thermochemical sulfur-ammonia water-splitting cycle: Photocatalytic hydrogen production stage

One of the main limitations of existing solar thermochemical water-splitting cycles (WSC) are that they utilize only thermal component of the solar irradiation neglecting its photonic component. A new hybrid photo-thermochemical sulfur–ammonia (HySA) WSC developed at the Florida Solar Energy Center allows circumventing this shortcoming. In the HySA cycle, water splitting occurs by means of solar beam splitting which enables utilization of the quantum (UV–Vis) portion of the solar spectrum in the hydrogen production stage and the thermal (IR) portion in the oxygen production stage. Present work investigates the photocatalytic hydrogen production step using narrow band gap CdS and CdSZnS composite photocatalysts, and ammonium sulfite as an electron donor. The choice of the electron donor was determined by the considerations of its regenerability in the thermal stages of the HySA cycle. This article examines the impact of photocatalyst and cocatalyst loading, temperature, and light intensity on hydrogen production rates. Photocatalysts, cocatalysts and photoreaction products were analyzed by a number of materials characterization (XRD, SEM, TEM, EDS) and analytical (GC and IC) methods. The experimental data obtained provide guidance for the improved solar photoreactor design.     

Investigations on the properties of ceria–zirconia-supported Ni and Rh catalysts and their performance in acetic acid steam reforming

The production of hydrogen via steam reforming of acetic acid was examined over Ni and Rh supported on a CeO₂–ZrO₂-mixed oxide. The catalysts were tested at 550–650–750 °C using steam/carbon = 3. Steam reforming, water gas shift, and decarboxylation are the main reactions taking place over the support alone. In parallel, dehydrogenation leads to the formation of carbon deposits on the surface of the mixed oxide. The addition of the metals enables the reforming reactions to proceed with high rates producing hydrogen yields close to thermodynamic equilibrium even at 650 °C. The oxygen exchange reactions are enhanced leading to much lower coke deposition. The nature of the metal affects not only the quantity but also the quality and the location of the carbon deposits, as evidenced from temperature-programing oxidation tests. The synergy of the support and metal is the key factor for the low coke deposition, which is even lower for the Rh catalyst.     

Effectiveness of a natural Rosemary (Rosmarinus officinalis) extract on the stability of filleted and minced fish during frozen storage

 The objective of this study was to evaluate the effect of adding a natural Rosemary (Rosmarinus officinalis L.) extract to filleted and minced frozen fish and to compare the fat stability of the samples with that of the controls. Horse mackerel (Trachurus trachurus), a relatively fatty fish, and Mediterranean hake (Merluccius mediterraneus), a low-fat fish, were used. Fat stability evaluation was done by comparing the changes of the malondialdehyde (MDA) content and the percentage of polyunsaturated fatty acid (PUFAs) degradation that occurred during frozen storage at –18°C for 120 days. Total volatile bases-N (TVB-N) were also measured to assess for quality. The results showed that the natural antioxidant extract retarded the oxidation process throughout storage. The control samples of both filleted and minced frozen fish of both species showed a significant reduction (^* P <0.05) of PUFAs until day 50 of storage, while the oxidation was gradual but slower in the treated samples. Fillets and minced samples of both species treated with antioxidant contained significantly (^* P <0.05) less MDA compared with the controls during storage. Received: 2 December 1996     

An approach for the modelling and quantification of PSS customisation

A Product–Service System (PSS) is a dynamic and multidimensional system that is comprised of products, services, a large network of stakeholders and all necessary supporting infrastructures, aiming towards becoming continuously competitive, satisfying customer needs and improving environmental aspects. The design of such a system and its evaluation throughout the lifecycle are challenging tasks owing to their inherent complexity, which becomes even greater when the aspect of customisation is considered. Nevertheless, the literature work regarding the customisation of PSS is scarce. Towards bridging this gap, the present work proposes a framework for PSS customisation, including the main steps that are required for a successful PSS customisation. For each step in the framework, which has been collected from the literature, PSS approaches have been provided, and could be used in the execution of each step. Next, the present study introduces a method for: (i) the modular representation of PSS based on vector analysis, and then (ii) the quantification of the PSS customisation degree.     

Sonophotocatalytic/H2O2 degradation of phenolic compounds in agro-industrial effluents

The treatment of a model solution containing 13 compounds typically found in olive mill wastewaters (OMW), at a concentration of 50 mg/L each, by means of sonophotocatalysis over 0.75 g/L Degussa TiO₂ suspensions was studied. Experiments were conducted at an ultrasound frequency and intensity of 80 kHz and 120 W, respectively, ultraviolet power of 9, 250 and 400 W with or without the addition of 0.118 mol/L H₂O₂. Treatment efficiency was assessed following changes in total phenols (TPh) concentration, individual species concentration, chemical oxygen demand (COD), total organic carbon (TOC) and ecotoxicity. In general, photocatalytic degradation increased with increasing UVA power, while sonolysis alone failed to cause any degradation. Process coupling and addition of extra oxidant resulted in substantial levels of degradation. For instance, sonophotocatalytic treatment at 400 W UVA power with H₂O₂ for 120 min resulted in complete mineralization followed by significant toxicity reduction. TiO₂ characterization before and after use showed that the catalyst suffered no composition or morphology changes during treatment. However, a substantial surface area increase was noted and this was attributed to the ultrasound de-aggregating catalyst particles. Preliminary tests with an actual OMW showed that the sonophotocatalytic/H₂O₂ treatment is a promising technology for this type of effluents.     

Storage stability of cooked sausages containing vegetable oils

Comminuted cooked sausages were produced using standard industrial practices, by substituting corn oil, sunflower oil, cotton seed oil, soybean oil and hydrogenated vegetable fat for animal fat. When processed, products were assessed for their stability with respect to autoxidation and change in organoleptic properties during vacuum-packed storage in a domestic refrigerator at 4 °C. Data obtained indicated that changes in thiobarbituric acid (TBA) values and organoleptic properties of products produced using corn oil, sunflower oil and hydrogenated vegetable fat were similar to those observed for reference material produced using lard. In the case of samples produced using soybean and cotton seed oil, TBA value changes were more pronounced, but did not exceed acceptable limits. A more rapid deterioration of organoleptic characteristics was also observed for the same samples, which showed flavour problems after 3 months of storage at 4 °C. Substitution of plant oils for lard considerably reduced the cholesterol content and increased the ratio of unsaturated to saturated fatty acids of cooked sausages.

---

Lagerungsstabilität von Brühwürsten, die mit verschiedenen pflanzlichen Ölen hergestellt wurden

Zusammenfassung Es wurden feinzerkleinerte Brühwürste unter Praxisbedingungen gefertigt, die anstelle des tierischen Fettes (Schweinespeck), pflanzliche Öle, wie Sonnenblumenöl, Maiskornöl, Sojabohnenöl, Baumwollsamenöl und Kokosnußsfett enthielten. Die Untersuchungen der fertigen Produkte erstreckten sich vor allem auf sensorische Eigenschaften und autoxidative Stabilität während der Kühllagerung bei 4 °C unter Vakuum. Die Ergebnisse haben gezeigt, daß die Änderungen der TBA-Werte und der organoleptischen Eigenschaften der Chargen mit Maiskornöl, Sonnenblumenöl und Kokosnußfett fast ähnlich wie die der Kontrollcharge (Schweinespeck) waren. Bei der Verwendung von Sojabohnenöl und Baumwoll-samenöl waren die Änderungen der TBA-Werte dagegen intensiver, ohne jedoch die obersterlaubte Grenze zu überschreiten. Hier wurde ebenfalls, nach einer dreimonatigen Lagerung bei 4 °C, eine unerwünschte Änderung ihrer organoleptischen Eigenschaften, vor allem des Aromas, beobachtet.

     

SEM studies of surfactant‐assisted micro‐mixing of melamine and wax particles

The validity of the micro‐mixing phenomenon was investigated by mixing a melamine dispersion, stabilized by low molecular mass poly(acrylic acid) (～5000 Daltons) and a wax emulsion, stabilized by an ethoxylated alkyl phenol surfactant. The wax particles were observed to be attached to the melamine surface because of the interaction between the poly(acrylic acid) dispersant and the ethoxylate group of the wax surfactant, resulting in the sedimentation of mixed particles. This phenomenon has potential application in the mixing of solid particles that require intimate contact and homogeneous mixing. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 2554–2557, 2006     

Levels of biogenic amines in retail market fermented meat products

The qualitative and quantitative profile of biogenic amines (BA) in 50 samples of dry fermented sausages sold in Greek retail markets were determined by HPLC. Putrescine, cadaverine, tryptamine, β-phenylethylamine spermidine, spermine were analysed by UV detection after pre-column derivatization with benzoyl chloride, whereas tyramine and histamine were analysed by fluorescence detection after post-column derivatization with o-phthaldialdehyde (OPA). With the exception of spermidine and spermine a wide variation of BA levels was observed among the samples. Of the BA examined, tyramine, putrescine, histamine and cadaverine showed high concentrations ranging from: 0 to 510 mg/kg (median: 197.7 mg/kg), 0 to 505 mg/kg (median: 96.5 mg/kg), 0 to 515 mg/kg (median: 7.0 mg/kg) and 0 to 690 mg/kg (median: 3.6 mg/kg), respectively. The histamine content of 28% of the samples exceeded the toxicity limit of 100 mg/kg set for histamine in some fish species. Levels of tryptamine and β-phenyl-ethylamine never exceeded 50 and 29 mg/kg, respectively. Results of the present study suggest that the amounts of BA in dry fermented sausages, sold in Greek retail markets, may pose a potential health risk for sensitive individuals or for those undergoing classical monoamine oxidase inhibiting (MAOI) drug therapy.     

Improving brain tumor characterization on MRI by probabilistic neural networks and non-linear transformation of textural features

The aim of the present study was to design, implement and evaluate a software system for discriminating between metastatic and primary brain tumors (gliomas and meningiomas) on MRI, employing textural features from routinely taken T1 post-contrast images. The proposed classifier is a modified probabilistic neural network (PNN), incorporating a non-linear least squares features transformation (LSFT) into the PNN classifier. Thirty-six textural features were extracted from each one of 67 T1-weighted post-contrast MR images (21 metastases, 19 meningiomas and 27 gliomas). LSFT enhanced the performance of the PNN, achieving classification accuracies of 95.24% for discriminating between metastatic and primary tumors and 93.48% for distinguishing gliomas from meningiomas. To improve the generalization of the proposed classification system, the external cross-validation method was also used, resulting in 71.43% and 81.25% accuracies in distinguishing metastatic from primary tumors and gliomas from meningiomas, respectively. LSFT improved PNN performance, increased class separability and resulted in dimensionality reduction.