Polyphosphates as inhibitors of surface mould growth on hard cheese during ripening

A novel treatment using polyphosphates to protect cheeses against superficial mould growth was assayed. The treatments were: control commercial paint with natamycin (I), commercial paint based on polyvinyl–water (II), immersion in a saturated solution of polyphosphate (III), immersion and commercial paint (IV), commercial paint of polyphosphate solutions (V) and immersion and commercial paint of a saturated solution of polyphosphates (VI). The cheeses were ripened for 6 months. Superficial mould growth was inhibited in groups IV and VI when compared to cheeses from the control group (I). Statistical sensory analysis made between cheeses from groups IV and I (control) showed no significant differences.     

COLD-CONDITIONING TREATMENT REDUCES CHILLING INJURY IN MEXICAN LIMES (CITRUS AURANTIFOLIA S.) STORED AT DIFFERENT TEMPERATURES

Induction of different antioxidant enzymes by high and low temperatures prior to storage has been reported to produce tolerance to chilling injury (CI). Thus, different prestorage temperatures have been suggested to decrease CI in citrus fruits. In this work, the effectiveness of a cold‐conditioning treatment (13C for 48 h) to prevent CI was evaluated in Mexican limes (Citrus aurantifolia S.) stored at 4, 10 and 25C, and 90% relative humidity. Cold conditioning reduced 1.6‐fold CI symptoms, induced a significant increase of 2.2‐fold peroxidase activity and maintained the activity of superoxide dismutase in limes kept at 4C. Our results suggest that the effectiveness of the cold‐conditioning treatment in increasing chilling tolerance in Mexican limes depends on the induction or maintenance of antioxidant enzymatic systems during the entire storage period.     

BASIC CONCEPTS IN RISK ANALYSIS AND THE DECISION-MAKING PROCESS

This paper presents a discussion on the basic concepts behind engineering safety and proposes a general framework, which considers risk analysis as a fundamental tool for the decision-making process in engineering. A discussion on the nature of damage and a characterisation of failures, accidents and disasters is presented. Then, a brief discussion on the existing failure modelling alternatives and requirements is given followed by a critical review on existing definitions of concepts such as hazard, vulnerability and risk. New strategies for understanding, modelling and carrying out hazard, vulnerability and risk assessments are proposed. Finally a general framework for the decision making process based on risk analysis is presented.     

Smith predictor design for robust performance

A method is outlined for designing Smith predictor controllers that provide robust performance despite real parameter uncertainties in the process model. Insight into the design process is gained by viewing the Smith predictor from the perspective of internal model control. Performance requirements are written in terms of a frequency-domain weight restricting the magnitude of the closed-loop sensitivity function. A general method for approximating multiple parameter uncertainties by a single multiplicative uncertainty is developed—an exact bound is derived for the magnitude of multiplicative uncertainty used to approximate simultaneous uncertainties in process gain, time-constant, and time-delay. Three different tuning methods are demonstrated; each is applied to a wide range of parameter uncertainties in a first-order with time-delay model. The first tuning method locates loop transfer-function uncertainty regions to test for robust performance—real parameter uncertainties are considered exactly. The second tuning method approximates real parameter uncertainties by multiplicative uncertainty and uses structured singular value analysis to guarantee robust performance. The third is a ‘quick design’ method that considers the unit magnitude crossing of the multiplicative uncertainty. Finally, the Smith predictor controller is compared with the structured-singular-value-optimal controller.     

不断发展的数据中心——专题报告：新趋势影响数据中心网络架构

企业制订业务目标来控制运营成本并提高业务灵活性,而数据中心使用的高新技术为满足这些业务目标提供了新方式。部署高新技术将帮助企业数据中心实现快速发展。