A novel method of shrimp blanching by CO2 heat pump: Quality,energy, and economy analysis

To reduce the energy consumption of the shrimp blanching process and improve the economic value of the blanched product, a transcritical CO₂ heat pump blanching system (THPB system) was designed in this paper. The trends of astaxanthin were investigated at atmospheric pressure near boiling temperature, combined with the color and structural properties of shrimp samples, and the optimal blanching times of 270 s and 240 s were obtained at 90°C and 95°C, respectively. In contrast to the fuel blanching system (FB system) at 100°C, the annual standard coal consumption of the THPB system with 90°C blanching is decreased by 79%, and the annual operating cost can be saved by CNY 63,800, with a payback period of about 3.13 years.Industrial relevanceBlanching is one of the effective ways to prolong the shelf life of shrimp. However, the research on the blanching time and temperature of shrimp is not comprehensive. In addition, the traditional fuel blanching process has high energy consumption and pollution, and can no longer meet the quality requirements of the modern food processing industry. Heat pump has been shown to have better performance in food drying, but it is less used in blanching. The information presented in this study may provide other insights into food processing.     

Incremental method evolution in global software product management: A retrospective case study

Company growth in a global setting causes challenges in the adaptation and maintenance of an organization’s methods. In this paper, we will analyze incremental method evolution in software product management in a global environment. We validate a method increment approach, based on method engineering principles, by applying it to a retrospective case study conducted at a large ERP vendor. The results show that the method increment types cover all increments that were found in the case study. Also, we identified the following lessons learned for company growth in a global software product management context: method increment drivers, such as the change of business strategy, vary during evolution; a shared infrastructure is critical for rollout; small increments facilitate gradual process improvement; and global involvement is critical. We then claim that method increments enable software companies to accommodate evolutionary adaptations of development process in agreement with the overall company expansion.     

Measurement on the structural,morphological, electrical and optical properties of PANI-CSA nanofilms

Camphorsulfonic acid doped polyaniline (PANI-CSA) prepared by chemical oxidative polymerization is spin coated on glass plates with four different PANI:CSA weight ratios (1:1, 1:2, 1:4 and 1:8) and measurements on the structural and optical properties are done. Thickness of the films measured <100 nm are termed as nanofilms. Fourier transform infrared spectroscopy indicated the presence of dopant and an increase in degree of polymerization with increase in dopant ratio. X-ray diffraction studies revealed the change of amorphous nature of the film to crystalline nature with increase in CSA dopant ratio. Scanning electron microscopy showed the change of very smooth morphology of the film to rough root-like morphology with increase in CSA dopant ratio. Hall-effect analysis showed that the increase in CSA weight ratio appreciably increases the conductivity of PANI-CSA films due to increase in carrier concentration and it also represents the semiconductivity (P-type) nature in all the films. UV–visible absorption studies reveal the broadening of absorption spectrum in visible region with maximum CSA dopant ratio (1:8). Photoluminescence spectra of PANI-CSA films excited using 300 nm, revealed that the change in intensity and position of emission peaks are due to transition of semiconducting nature of the film to conducting nature with an increase in CSA dopant ratio from 1:1 to 1:8.     

Astaxanthin extraction from Haematococcus pluvialis using CO2-expanded ethanol

Microalgae represent diverse branch of microorganism that can produce a wide range of unique functional ingredients that can be used in food, cosmetics, pharmaceuticals, and energy. Among them, Haematococcus pluvialis is known for accumulating the highest levels of a potent natural antioxidant, astaxanthin, which has demonstrated positive health effects. Therefore, the aim of numerous studies has been to develop novel and efficient extraction techniques to produce high-quality (purity and antioxidant activity) extracts, while complying with the Green Chemistry Principles. Supercritical CO₂ (scCO₂) emerges as an alternative to organic solvents because of its high selectivity and bioactivity-preserving qualities. Nevertheless, astaxanthin is a large molecule with low solubility in scCO₂ that usually requires long extractions at high pressures. Ethanol has been used as co-solvent to increase astaxanthin solubility in scCO₂. In this work, a Box–Behnken experimental design was used to study the effects of operating pressure (20–35 MPa), temperature (40–70 °C), and ethanol content in scCO₂ (0–13%, w/w) on the yield, astaxanthin content, and antioxidant activity of H. pluvialis extract. Results showed that ethanol content in CO₂ has a more significant effect on all responses than pressure and temperature. These results lead us to investigate the effect of a further increase in ethanol content, up to the region of gas-expanded liquids. We studied the effects of temperature (30–60 °C) and ethanol content (50–70%, w/w) at a fixed pressure (7 MPa) on the same response variables using CO₂-expanded ethanol (CXE). Results showed that temperature and ethanol content had a significant influence on astaxanthin yield and antioxidant activity. Also, the overall responses of CXE surpassed scCO₂ extractions to match conventional extraction with acetone, maintaining high quality extracts, thus validating the use of this new type of green technology for extraction of high-value compounds.     

The effect of CuO coatings on the electrokinetic properties of stone wool fibres determined by streaming potential measurements

Commercial stone wool fibres were modified with copper(II) oxide coatings. This oxide is widely used in processes of surface modification for filter materials to improve its bacterial retention. The microorganisms are already susceptible to low concentrations of copper in contrast to humans for which copper is an inert material in the concentration range. Additionally, the coatings changed the electrokinetic properties of the fibres. As a result, the isoelectric point (IEP) of the untreated fibres was shifted from acidic towards a more basic pH range. A positive or no charge on the surface of the fibres allows them to be a substrate for the positively charged adsorbents of negatively charged waterborne contaminants with the use of electrostatic adsorption. The coatings were prepared by dip coating with the use of two different coating precursors: the aqueous suspension of CuO nanoparticles and aqueous solutions of copper(II) nitrate trihydrate or copper(II) acetate or a mixture of thereof. The zeta potential of the modified fibres was determined by a streaming potential method. The adhesion of the coatings was tested by flushing and ultrasonication of the modified fibres. The isoelectric point of the fibres was shifted towards a more basic pH range for all precursors with the largest impact of the copper(II) nitrate trihydrate precursor. This coating changed the IEP of the fibres from 4.1 to 8.3 pH value. The highest calculated coverage of the coatings was in the range of 54% and was obtained by using copper(II) nitrate trihydrate/CuO nanoparticles precursor. Although, we do not predict such modified fibres to act as a standalone water filter, we believe they have the potential to be an excellent support material for active adsorbents.     

Functionalization of multi-wall carbon nanotubes to reduce the coefficient of the friction and improve the wear resistance of multi-wall carbon nanotube/epoxy composites

Functionalization of multi-wall carbon nanotubes (MWCNTs) was achieved by grafting carboxyl groups and amino groups. Fourier transform infrared spectroscopy was used to detect the changes produced by functional groups on the surface of the MWCNTs. Three different MWCNTs were incorporated into epoxy resin and the friction and wear behavior of MWCNT/epoxy composites was investigated using a M-2000 wear testing machine at different sliding speeds under different applied loads. Scanning electron microscopy was used to observe the worn surfaces of the samples. The results indicated that the functional groups had been grafted on the surface of MWCNTs. Compared with neat epoxy, the composites with MWCNTs showed a lower friction coefficient and wear rate, and the wear rate decreased with the increase of MWCNT loading. Combining epoxy resin with MWCNTs is an efficient method to improve the wear resistance and decrease the coefficient of friction.     

A new bonded vertical joint design for architectural panels

This paper presents a new bonded vertical joint design for façade architectural panels which improves the façade behaviour under static and dynamic loads and enhances durability. Furthermore, it overcomes more of the structural, construction and aesthetic problems that could appear on precast façade panels. This study reports the current problems of steel façade panels and the advantages achieved with the new vertical joint design, bonded with a toughened epoxy resin. The experimental study of the new joint behaviour includes mechanical standard tests on the adhesive behaviour and non-standard static and dynamic tests performed on half scale mild steel specimens bonded with the toughened epoxy resin in order to determine its mechanical behaviour under external loads. The experimental results can be useful to calibrate numerical models of the new joint behaviour.     

Real-time TaqMan PCR for quantitative detection of cows’ milk in ewes’ milk mixtures

A real-time PCR based on the amplification of a fragment of the mitochondrial 12S ribosomal RNA gene was developed and evaluated for the detection and quantification of cows’ milk in raw and heat-treated cow/sheep milk mixtures. The method combines the use of cow-specific primers that amplify a 252 bp fragment from cow DNA, and mammalian-specific primers amplifying a 428 bp fragment from mammalian species DNA, which is used as an endogenous control. The method measures PCR product accumulation through a 6-carboxyfluorescein-labeled fluorogenic probe (TaqMan). A comparison of the cycle number at which mammalian and cow-specific PCR products were first detected, in combination with the use of reference standards of known bovine content, allowed the determination of the percentage of cows’ milk in mixtures. Experimental raw and heat-treated binary mixtures were analyzed, demonstrating the specificity and sensitivity of the assay for detection and quantification of cows’ milk in the range 0.5–10%.     

Simultaneous determination of cholesterol oxides,cholesterol and fatty acids in processed turkey meat products

Cholesterol oxides, cholesterol, total lipids and fatty acids were determined in the lipid extracts from eight processed turkey meat products (blanquet, frankfurter, ham, meatball, smoked breast, smoked ham and roule). Cholesterol and cholesterol oxides were determined simultaneously by high performance liquid chromatography using a diode array detector at 210 nm and a refractive index detector. Only two cholesterol oxides were identified, 7-ketocholesterol (not detected up to 184 μg/100 g) and β-epoxycholesterol (not detected up to 450 μg/100 g). With the exception of the meatballs, hamburger and frankfurters, all the turkey meat products showed less than 5% fat, and could thus be considered as low fat foods. The cholesterol content varied from 32 to 43 mg/100 g, the ratio of polyunsaturated:saturated fatty acids varied from 1.1 to 1.8 and the ratio of ω6:ω3 from 18 to 28. Trans fatty acids were present in significant amounts in both hamburger and meatball.