Long and short term storage of table grapes

Grapes are very perishable commodities, and the different cultivars react differently to cold storage. Length of storage is thus limited by certain factors. In such conditions, the methods of handling, packaging and of special cooling are essential for the delivery of dessert grapes in optimum condition, independent of the fact that the time between harvest and delivery to the consumer may range from some days to a month.The authors consider the various factors involved in relation to storage, namely the cultivar, the texture of the fruits, cultural and production factors, handling and packaging, use of biochemical treatments, deterioration of the fruits, and precooling after harvest.The paper then deals with storage for short, medium and long terms, in the latter case using a plastic tent inside the cold store, functioning as a jacketed store. In all three types of storage, the most important factor is action against rotting; sulphur dioxide is a relatively efficacious agent with, however, certain somewhat undesirable features which necessitate continuation of research in order to find a non-toxic anti-fungal agent for grapes.     

An analytical comparison of long and short term contracts

In this paper, we describe an analytical model to determine contracting policies for a firm that purchases components from external suppliers. The model evaluates the tradeoff between the flexibility offered by short term contracts arid the fixed investments, improvement opportunities and price certainty associated with long term contracts. We show that long term contracts may not always be optimal, and discuss conditions under which short term contracts may be justified. During a recent survey of supply managers, we observed that managers often tend to participate in short term contracts, even though they claim to seek long term relationships with suppliers. Sensitivity analysis of our model provides some explanation for this observed inconsistency. We also discuss managerial implications of the analysis.     

Patents in nanotechnology: an analysis using macro-indicators and forecasting curves

In this study, we evaluated future trends of worldwide patenting in nanotechnology and its domains using logistic growth curves while the patent activity from the main countries, technological domains and subdomains were assessed in four different contexts: worldwide, patents filed in the United States Patent and Trademark Office (USPTO), and patents applications in the triadic (TRIAD) and in the tetradic (TETRAD) countries. The indicators were developed based on a set of records recovered from the Derwent Innovation Index database. Nanotechnology has recently emerged as a new research field, with logistic trend behaviors generating interesting discussions since they suggest that technological development in nanotechnology and its domains has reached an initial maturation stage. Future scenarios were compiled due to the difficult to establish upper limits to forecasting curves. Although China’s share of patents is small in some cases, it was the only country to constantly increase the number of patents from a worldwide perspective. In contrast, the USA and the EU were the most active in the USPTO, TRIAD and TETRAD cases, followed by Japan and Korea. The technological subdomains of main interest from countries/region changed according to the perspective adopted, even though there was a clear bias towards semiconductors, surface treatments, electrical components, macromolecular chemistry, materials–metallurgy, pharmacy–cosmetics and analysis–measurement–control subdomains. We conclude that monitoring nanotechnology advances should be constantly reviewed in order to confirm the evidence observed and forecasted.     

Ratio of short term and long term impact factors and similarities of chemistry journals represented by references

Some important bibliometric characteristics of chemistry journals were studied. Contrary to expectations, calculations of impact factors asynchronized for shorter and longer periods yield similar values. A new overlap measure for journals is suggested which is based on frequency distribution of references by journals.     

Crack width prediction of FRC beams in short and long term bending condition

The use of short fibers inside concrete matrix is an effective method for reducing the vulnerability of concrete constructions subjected to harsh environment. The action of the short fibers in reducing the crack opening is the main issue that needs a research effort in order to optimize the expected results. At the moment the analytical prediction of the crack width and spacing in fiber reinforced concrete (FRC) structural elements under bending loads is still an open problem. A crack width relationship for FRC/RC elements similar to those developed for plain concrete structural members would be desirable for designers and engineers involved in the design of FRC structural elements. The recent development of important technical design codes, such as RILEM TC 162 TDF and the new Model Code (MC) 2010, embrace this idea. However further validation of these models by experimental results is still needed. On the other hand the study of the influence of a sustained load on crack width in presence of a short fibers reinforcement is a topic almost unexplored and important at the same time. In this research the cracking behaviour of full-scale concrete beams reinforced with both traditional steel bars and short fibers has been analyzed under short and long term bending condition. A theoretical prediction of crack width and crack spacing was carried out according to international design provisions based on different analytical models. The theoretical results are discussed and compared in order to highlight the differences between the available models and to check the reliability of the theoretical predictions on the basis of the experimental data. A modified relationship to take into account of the presence of stirrups has been proposed on the basis of experimental results; furthermore, some critical aspects, such as the influence of the type of fibers and the effect of loading-time, have been underlined that should be addressed in future research work.     

The evolution of family level sales forecasts into product level forecasts: Modeling and estimation

It is frequently the case that sales forecasts are available at the detailed product level for only a relatively short time horizon. For the rest of the forecast horizon, only aggregate sales forecasts at the product family level are available. The problem addressed in this paper is how to fit a forecast simulation model to a history of these aggregate and disaggregate forecasts. Our approach to develop such a model is to combine a forecast update model with a forecast disaggregation model. The forecast update model is called the Martingale model of forecast evolution. The parameters of the two models must be estimated from historical forecast data. It is this statistical parameter estimation problem that occupies the major part of our investigation. We recommend an estimation technique based on the method of moments.     

Modeling and analysis of dynamic robust design experiments

This paper investigates the response model approach for the dynamic robust design problem. We derive relationships between the effect estimates of the loss model approach and those of the response model approach. We show that the bias problem for the static case solely exists in the estimation of process variance and does not exist in the estimation of the slope and intercept parameters. The two analysis approaches are compared by use of a real example.     

Highly cited papers in rheumatology: identification and conceptual analysis

Scientometrics - Rheumatology is a broad research area with an extensive background in scientific publications. Thus, the present study aims to identify the highly cited papers in Rheumatology...     

Combining task analysis and fault tree analysis for accident and incident analysis: A case study from Bulgaria

Understanding the reasons for incident and accident occurrence is important for an organization's safety. Different methods have been developed to achieve this goal. To better understand the human behaviour in incident occurrence we propose an analysis concept that combines Fault Tree Analysis (FTA) and Task Analysis (TA). The former method identifies the root causes of an accident/incident, while the latter analyses the way people perform the tasks in their work environment and how they interact with machines or colleagues. These methods were complemented with the use of the Human Error Identification in System Tools (HEIST) methodology and the concept of Performance Shaping Factors (PSF) to deepen the insight into the error modes of an operator's behaviour. HEIST shows the external error modes that caused the human error and the factors that prompted the human to err. To show the validity of the approach, a case study at a Bulgarian Hydro power plant was carried out. An incident – the flooding of the plant's basement – was analysed by combining the afore-mentioned methods. The case study shows that Task Analysis in combination with other methods can be applied successfully to human error analysis, revealing details about erroneous actions in a realistic situation.     

Comparison between the short and long term behaviour of fibre reinforced and unreinforced concrete beams

The paper deals with the results of tests on concrete beams with and without steel fibres, reinforced (with high yield flexural steel only) and without any reinforcement loaded statically both long and short term. Tests were carried out for both serviceability and ultimate limit states. Measurements were taken of load, strains, crack width and crack pattern, and deflection. For short term loading the beams were loaded incrementally to failure, whilst for the long term tests were loaded incrementally to their service load which was maintained for 28 days before being increased to failure. From the long term tests the effects of creep can be determined.

A total of 15 beams were tested over 28 days. The fibres were stainless steel with an aspect ratio of 55 and a volume fraction of 1·5%. In all cases the results indicate successively better performances as fibre reinforcement and bar reinforcement were added.     

State-space based analysis and forecasting of macroscopic road safety trends in Greece

In this paper, macroscopic road safety trends in Greece are analyzed using state-space models and data for 52 years (1960–2011). Seemingly unrelated time series equations (SUTSE) models are developed first, followed by richer latent risk time-series (LRT) models. As reliable estimates of vehicle-kilometers are not available for Greece, the number of vehicles in circulation is used as a proxy to the exposure. Alternative considered models are presented and discussed, including diagnostics for the assessment of their model quality and recommendations for further enrichment of this model. Important interventions were incorporated in the models developed (1986 financial crisis, 1991 old-car exchange scheme, 1996 new road fatality definition) and found statistically significant. Furthermore, the forecasting results using data up to 2008 were compared with final actual data (2009–2011) indicating that the models perform properly, even in unusual situations, like the current strong financial crisis in Greece. Forecasting results up to 2020 are also presented and compared with the forecasts of a model that explicitly considers the currently on-going recession. Modeling the recession, and assuming that it will end by 2013, results in more reasonable estimates of risk and vehicle-kilometers for the 2020 horizon. This research demonstrates the benefits of using advanced state-space modeling techniques for modeling macroscopic road safety trends, such as allowing the explicit modeling of interventions. The challenges associated with the application of such state-of-the-art models for macroscopic phenomena, such as traffic fatalities in a region or country, are also highlighted. Furthermore, it is demonstrated that it is possible to apply such complex models using the relatively short time-series that are available in macroscopic road safety analysis.     

ECG analysis: a new approach in human identification

A new approach in human identification is investigated. For this purpose, a standard 12-lead electrocardiogram (ECG) recorded during rest is used. Selected features extracted from the ECG are used to identify a person in a predetermined group. Multivariate analysis is used for the identification task. Experiments show that it is possible to identify a person by features extracted from one lead only. Hence, only three electrodes have to be attached on the person to be identified. This makes the method applicable without too much effort     

气动弹性系统的模型确认与鲁棒颤振分析

研究了气动弹性系统的不确定性建模和鲁棒颤振分析问题.将结构的不确定性考虑为参数形式,非定常气动力的不确定性考虑为参数和未建模动态两种形式,建立了不确定系统的线性分式变换模型.分别使用基于Carathe-dory-Fejer插值定理和Nevanlinna-Pick插值定理的模型集检验方法进行了模型确认,在时间域和频率域中对模型集的有效性进行了验证,确定了不确定性的幅值.对于模型确认得到的不确定气动弹性系统,使用μ分析方法进行了鲁棒颤振分析.计算中,飞行速度是作为给定参数而不再是作为摄动变量,由此得到的鲁棒稳定性边界是匹配点解.仿真数值结果给出了鲁棒颤振速度,表明了方法的有效性.     

Representative static load models for transient stability analysis: development and examination

Load representation has a significant impact on power system analysis and control results. Currently, static load models are still popular in power industry for transient stability analysis. Dynamic load models are recommended in both industry and academia for possible improvement in analysis accuracy. The accuracy of using static (nonlinear) load models with suitably identified parameters for transient stability analysis is examined. Numerical studies conducted using on-line measurement data indicate that static load models, as compared with induction motor load models, are acceptable for modelling real power behaviours during disturbances and hence are adequate for transient stability analysis. Using multiple sets of on-line measurements, representative model parameters of five static nonlinear load models are derived and their performance in modelling dynamic behaviours of both real and reactive powers is compared. A method is presented to determine a representative set of parameters of static (nonlinear) load models for each loading condition     

Empirical modeling and robust control of a novel meso-scale vapor compression refrigeration system (mVCRS)

This paper presents an empirical modeling and robust control of a novel meso-scale vapor compression refrigeration system (mVCRS). The objective of this study is to maintain a temperature of heat source via the mVCRS against the cooling loads varying from 30 W to 80 W. To this end, the proposed mVCRS is identified by using a black-box model under various cooling loads and the robust control system is chosen to achieve the desired cooling capacity and the temperature tracking capability. For various cooling loads, the experiments using the mVCRS are carried out, which demonstrate that even for its compactness, the maximum cooling load of proposed mVCRS is 80 W with maintaining the temperature of the heat source around 46 °C with the help of a robust controller and, the temperature of heat source converges to the desired one within 70 sec and is minimally bounded by 1.25 °C irrespective of the cooling load.     

Dynamic sensitivity analysis of material and load parameters in nonlocal elasticity

Dynamic sensitivity analysis of a general performance functional in nonlocal elasticity is performed with respect to material parameters and loading functions. The adjoint variable method is employed in order to evaluate the first variation of the functional with respect to the decision variables. It is found that, in an iterative solution procedure, while the primary problem is solved forward in time, an adjoint problem must be integrated backwards.     

Interruptible load considerations in well-being analysis of interconnected systems

Adequate operating reserve is required in an electric power system in order to maintain a desired level of reliability throughout a given period of time. Interruptible load can be considered as a part of the system operating reserve if it is required. The inclusion of interruptible load in the assessment of unit commitment in interconnected systems is illustrated in this paper using a well-being framework. A technique is presented to determine the well-being indices of both isolated and interconnected systems with the inclusion of interruptible load. The impacts on the required number of committed units and the well-being indices of the amount of interruptible load and the corresponding interruption time are examined in this paper by application to a hypothetical system and to the IEEE-RTS. © 1998 John Wiley & Sons, Ltd.     

Propagation of physically short cracks in a bainitic high strength bearing steel due to fatigue load

Physically short cracks in a bainitic high strength bearing steel were fatigue loaded. The rapid propagation rate of early open short cracks agreed with that of long closure free cracks. After some rapid growth, the short cracks entered a transition period to the rate of growth limited long cracks. Potential drop showed that the short cracks were open to the tip throughout the growth sequence, which excluded crack face closure in the wake as the growth limiting mechanism in this material. Instead the short crack effect was related to residual stresses and other mechanisms at the crack tip. Crack manufacturing procedures were determined for straight long and short start cracks in the present material. LEFM with effective material parameters and limit compensation predicted the short crack lives.     

短路过渡电弧的Lyapunov指数分析

为了更好地理解短路过渡气体保护电弧焊的不稳定性,尝试用混沌理论研究这一现象.介绍了A.Wolf理论和相空间重构理论,论述了用于选择重构参数的改进虚假邻近点法和重构信号强度法.利用这些相关的混沌理论及算法,对较稳定和不稳定的两组电流波形数据的最大Lyapunov指数(LE)进行了计算与分析.结果表明:短路过渡电弧是一个复杂的混沌过程,且随着电弧的不稳定性增加,该过程的混沌性增加;最大LE可用于表征短路过渡电弧的稳定性.     

Task analysis for error identification: Theory,method and validation

This paper presents the underlying theory of Task Analysis for Error Identification. The aim is to illustrate the development of a method that has been proposed for the evaluation of prototypical designs from the perspective of predicting human error. The paper presents the method applied to representative examples. The methodology is considered in terms of the various validation studies that have been conducted, and is discussed in the light of a specific case study.