Microbial Sensors for the Detection of Fish Freshness

A microbial sensor system consisting of immobilized living spoilage-causing bacterium, Alteromonas putrefaciens, and an oxygen electrode was prepared and applied to the continuous determination of fish freshness. Fish freshness was expressed as a ratio of A/B, where A is the current decrease of the microbial sensor obtained by the application of l0–50 μL fish extract and B is the current decrease by the equivalent volume of culture medium. Freshness of bluefin tuna and yellowtail meats stored in ice for up to 2 weeks was determined by both the proposed and the conventional K value enzyme sensor method. Good comparative results were obtained. One assay could be completed within 13 min.     

铝合金单层网壳结构的工程应用与研究进展

近年来由于铝合金材料强度高、质量轻、耐腐蚀等优点,铝合金单层网壳被广泛应用在工程中.对近20年来铝合金单层网壳典型工程的结构形式、荷载以及受力特点等进行分类介绍,并论述了该类结构在设计和施工中所取得的成果,总结了铝合金单层网壳的各类科研成果,探讨了该领域今后需要进一步研究的问题,并提出了若干建议.     

L2-bounded stability for a stochastic system†

Both types of linear and non-linear systems with random coefficients are treated in this paper. Four theorems are proved by using the stochastic Liapunov functional, which give the sufficient condition in matrix form for exponential asymptotic stability in the largo with probability one and L₂-bounded stability with probability one.     

BIOGAS RECOVERY FROM A THERMALLY TREATED SEWAGE SLUDGE BY A FIXED-BED ANAEROBIC BIOREACTOR

Biogas recovery from the anaerobic digestion of sewage sludge which is discharged from municipal wastewater treatments generally requires a large scale digester owing to the slow biodegradability of the sludge compounds. To achieve an effective methanogenesis from the sludge as the raw materials, thermal pretreatmenls of the sludge were conducted to improve the sedimentation efficiency of the treated sludge and the filtrate obtained was anaerobically digested in fixed-bed bioreactors with baked clay, melted slug and rhyolitic lava.

Methane formation from the intact activated sludge (10g/l) was 11 methane/I after 25-day fermentation without heat treatment (control), whereas in the case of treating for 1 h at 121°C, 2.1 I methane/I was produced from the whole treated sludge (10g/l) and 2.91 methane/1 was produced at pH 4 at the same heat treatment. However, no more methane was produced when the sludge was treated with 0.1 N NaOH or H₂SO₄ at 121°C for 1 h although lower fatty acids were accumulated.

The filtrates from heat treated sludge either at 121°C for 1 h at pH 4 or at 121°C for 1 h contained 2200 and 4400 mg COD/I, respectively. The filtrates obtained were anaerobically digested in fixed bed reactors. For the former, at COD loading 32.4g/l/day, the methane production rate was 2.91/l/day with 52.6% of COD reduction at 1.5 h of hydraulic retention time, whereas, for the latter, methane production rate was 2.11/1/day with 26.2% of COD reduction at 2.4 h retention time (COD loading 47.8).

It would be concluded that the heat treatments of discharged sludge from aeration tank might be a promising means for the treatment of activated sludge since the heat treatment could decrease the specific resistance of filtration of sludge and the filtrate discharged could be easily converted to methane as a fuel energy.     

DECOMPOSITION BEHAVIOR AND MECHANISM OF CALCIUM SULFATE UNDER THE CONDITION OF O2/CO2 PULVERIZED COAL COMBUSTION

The decomposition behavior and mechanism of calcium sulfate in O₂/CO₂ pulverized coal combustion were studied in an entrained flow reactor. A reaction rate expression correlating the influence of various factors was proposed for CaS0₄ decomposition and it is able to predict CaS0₄ decomposition satisfactorily. Under the conditions investigated, the decomposition of CaS0₄ was found to be a regime of chemically controlled shrinking core reaction. A CO₂-rich atmosphere enhances CaSO₄ decomposition in absence of oxygen. CaSO₄ particles have catalytic effect on formation of CO from CO₂. A high SO₂ concentration inhibits CaSO₄ decomposition. The kinetics of CaSO₄decomposition has obvious dependence on experimental facilities and conditions, whereas the activation energy has much lower dependence. The kinetics derived in this work is more appropriate for investigating desulfurization in O₂/CO₂ pulverized coal combustion because an entrained flow reactor has a much closer condition to that in O₂/CO₂ pulverized coal combustion than a TGA.     

Robust control for a constantly rising temperature system (Hm control approach)

Thermoluminescence dating has attracted the attention of geology and archaeology researchers as a new method. This method requires a heating device to raise the temperature of the specimens at an exact rate. This paper describes the design method of a control system that can achieve this goal. This control system lends to be unstable because of the existence of the parameter perturbation and dead time. In this paper, the perturbation and dead time are treated as perturbations of a nominal plant regarded as a first-order lag time system. Improvement of tracking characteristics in the low-frequency domain and robust stability in the high-frequency domain of the control system are achieved by using the solution of the mixed-sensitivity problem that is a kind of H^∞ control theory. Experiments verify the effectiveness of this method.     

A comparison between ceramic and polymeric membrane systems for casein concentrate manufacture

Skim milk microfiltration (MF) is a well established dairy processing operation to remove whey proteins. This is classically completed using ceramic membranes under the uniform transmembrane pressure (UTMP) concept. However, there is a growing interest in the use of spiral wound polymeric membranes for this purpose due to their lower capital cost. In this work we show that polymeric and ceramic membranes provide comparable performance during skim milk MF when operated at comparable levels of transmembrane pressure (TMP), shear stress and temperature. Operation is strongly affected by both TMP and temperature but is less affected by crossflow velocity under the conditions utilised here. However, while polymeric membranes offer similar performance, it will be operationally difficult to retain the necessarily low TMP at the industrial scale, due to the lack of a comparable UTMP configuration.     

SOME PROPERTIES OF MYOFIBRILLAR PROTEINS OBTAINED FROM LOW IONIC STRENGTH EXTRACTS OF WASHED MYOFIBRILS FROM PRE- AND POST-RIGOR CHICKEN PECTORAL MUSCLE

SUMMARY— Changes in extractability of the proteins associated with the fragmentation phenomenon of myofibrils in chicken pectoral muscle were studied. The results indicate that the protein fractions extracted by neutralized water from muscle residue. from which water-soluble proteins have been washed out, increase in post-rigor muscle. The extracts from pre- and post-rigor muscle were fractionated with ammonium sulfate into two fractions: the fraction precipitated by 1.7 M ammonium sulfate (Fr.1) and the supernatant (Fr. 2). Depressing effect on the onset of ATP-induced superprecipitation of trypsin-treated myosin 6 which was initially present in Fr. 2 from pre-rigor muscle decreased to a great extent in that from post-rigor muscle, whereas promotive effect on gelation of F-actin and superprecipitation of the myosin 6 which was little in Fr. 1 from pre-rigor muscle appeared in that from post-rigor muscle. It is proposed that an increasing amount of protein which indicates α-actinin activity is released along with the destruction and final dissolution of the Z-line structure during postmortem storage of chicken pectoral muscle.     

Cost‐Benefit Analysis of Renewable Installation in Inter‐Intelligent Renewable Energy Network

In this paper, we target the specific smart grid concept called “inter‐intelligent renewable energy network (i‐Rene),” which is characteristically associated with photovoltaic (PV) panels, microstorage, and regional electricity markets. In this smart grid, every house has an artificial intelligence agent that learns the optimal treading strategy to minimize payments by residents. From the economic standpoint, we perform a cost‐benefit analysis (CBA) of the optimal installation of PV panels and microstorage in this smart grid. To perform the CBA, we use actual measured values of power demand profiles and power production profiles, which were obtained in 2010 at Shiga, Japan. In accordance with this analysis, we also discuss the necessary conditions for achieving grid parity of the i‐Rene smart grid .     

Development of Hybrid Solar Systems Using Solar Thermal,Photovoltaics, and Wind Energy Translation from “Journal of the Japanese Solar Energy Society,” Volume 11, Number 4, page 15

Finite time exergoeconomic performance optimization of a universal irreversible heat-engine cycle model, which consists of two constant thermal-capacity heating branches, two constant thermal-capacity cooling branches and two adiabatic branches, is investigated by taking the profit rate criterion as the optimization objective. The analytical formulae for power, efficiency and profit rate function of the universal irreversible heat-engine cycle model with the losses of heat transfer, heat leakage and internal irreversibility are derived. The focus of this article is to search the compromised optimization between economics (profit rate) and the energy utilization factor (efficiency) for irreversible cycles. Moreover, analysis and optimization of the model are carried out in order to investigate the effects of these losses and cycle process on the performance of the universal irreversible heat-engine cycle model using numerical examples. The results obtained herein include the performance characteristics of seven typical irreversible heat engines, including Carnot, Diesel, Otto, Atkinson, Brayton, Dual and Miller cycles.