pinecone/core-2020-05-10-deduplication huggingface dataset:
Plant layout and pick-and-place strategies for improving performances in secondary packaging plants of food products

The aim of secondary packaging plants is to pick food products from a conveyor belt and to place them into boxes. The typical configuration of these packaging plants consists of a set of sequential robot stations, performing pick and place cycles from one conveyor to another parallel one, which transport the products and the boxes to be filled. Depending on the relative movement of the two conveyors, the plant operates in co-current or counter-current flow configuration. Undesired perturbations in the product flow rate from its nominal value can lead to critical events, i.e. unpicked product at the end of the first conveyor or not-completely filled boxes. Even if the structures of co-current flow and of counter-current flow plants, are very similar, their behaviour in non-nominal or perturbed conditions can be significantly different. The aim of this paper is to deeply investigate the behaviour of these two kinds of secondary packaging lines, evaluating their performances in the case of different pick and place strategies, using discrete events simulation techniques. Results show to which extent the different proposed control strategies can improve the performances of both co-current and counter-currents plants and, in particular, how co-current plant layouts can achieve performances which are equivalent to, or perhaps even better than, those that can be obtained with a counter-current plant layout, that cannot be freely used since it has been patented. The simulation tool, control algorithms and results presented can help packaging plant designers for choosing the most appropriate solutions and for properly sizing the plant. Copyright © 2012 John Wiley & Sons, Lt
An empirical investigation into the influence of sealing crimp geometry and process settings on the seal integrity of traditional and biopolymer packaging materials

This paper presents the results of investigations to determine how process settings and crimp geometry affect the seal strength and integrity of traditional polyolefin and biopolymer flexible packaging materials. The results show agreement with previous studies where temperature and dwell time are found to be the dominant factors for both polyolefin and biopolymer films. Pressure and crimp geometry are shown to be secondary factors in the process, up to the point of squeezing the film into molecular contact. In general it is shown that biopolymers exhibit similar sealing characteristics to more traditional films. In respect of the sealing crimp geometry it is shown that the crimp pitch has little or no effect on sealing integrity for films with gauges between 25µm and 40µm. But, for the same gauge material, crimp angles greater than 80° offer the greatest potential to gain higher seal strengths. It is further shown that with the cellulose and PLA films tested, a higher seal strength can be produced with crimp pitches of 2mm and lower. Also presented are some more general implications for guiding the selection of sealing crimp geometry and their usage with biopolymers
An Extended Method to Measure Overall Consumer Satisfactionwith Packaging

This is the authors’ final, accepted and refereed manuscript to the article. Publisher’s version available at http://dx.doi.org/10.1002/pts.2064There are several reasons why people find it troublesome to use and handle consumer packages. A test method for evaluating the ease of opening of such packages was presented in the “Technical Specification” (TS) [1]. The present study has expanded the procedure by including consumer satisfaction measurements in two steps and engaging panels comprising two separate age groups. The expanded method, which used six different packages as test objects, engaged 75 panelists, 40 in the older group (65–80 years), and 35 in the younger group (25–40 years). The expanded method included the same operations as described in the TS, but also included panelists who graded each handling element separately on a “smiley” scale, along with feedback for their grades, and an overall judgment of the package handling.

The grading feedback differed between the two groups. The younger panelists mainly noted issues that were not connected to openability, while older panelists noted openability as the most influential factor. Further analysis revealed that openability was also a key issue for the younger panelists, despite their claims to the contrary. Satisfaction was the most critical TS element for describing a package as being easy to open.1, Forfatterversjo
The effect of laser power, traverse velocity and spot size on the peel resistance of a polypropylene/adhesive bond

Abstract		\ud
The mean peel resistance force achieved with respect to variation in the laser power, incident\ud
spot traverse velocity and incident spot diameter between linear low density polyethylene\ud
film backed by a thin commercial adhesive coating that were bonded to a polypropylene\ud
substrate via thermal activation provided by a 27W CO\ud
2 laser is discussed in this work.\ud
The results gathered for this work have been used to generate a novel empirical tool that\ud
predicts the CO\ud
2 laser power required to achieve a viable adhesive bond for this material\ud
combination. This predictive tool will enable the packaging industry to achieve markedly\ud
increased financial yield, process efficiency, reduced material waste and process flexibility.\ud
A laser spot size dependent linear increase in laser line energy was necessary for this material\ud
combination, suggesting the minimal impact of thermal strain rate. Moreover a high level of\ud
repeatability around this threshold laser line energy was indicated, suggesting that laser\ud
activated adhesive bonding of such polymer films is viable.\ud
The adhesion between the material combination trialled here responded linearly to thermal\ud
load. In particular, when using the smallest diameter laser spot, it is proposed that the\ud
resulting high irradiance caused film or adhesive material damage; thus, resulting in reduced\ud
peel resistance force.\ud
The experimental work conducted indicated that the processing window of an incident CO\ud
2\ud
laser spot increases with respect to spot diameter, simultaneously yielding greater bond\ud
stability in the face of short-term laser variance
Evaluation of the accessibility of selected packaging by comparison of quantitative measurements of the opening forces and qualitative surveys through focus group studies

It can be expected that many elderly people have impaired opening capacity of food packaging bearing in mind the changes in functionality and physical strength that occur during ageing. This study determined the relation of the quantitative force required to open selected food packaging systems with findings derived from qualitative focus group studies to retrieve comprehensive information on the specific needs of seniors. The focus group studies revealed that the assessment of the ease of opening is very subjective and can vary from objective measurements. The quantitative measurement of the force required to open the ‘easy to open’ thermoformed tray resulted in considerably higher peel initiation forces of 22.50 ± 1.62 N compared to the standard tray (12.80 ± 1.93 N). However, the packaging type was still felt to be easier to open because of the enlarged tab and peeling corner, which was said to be easy to grip. Conversely, the stand-up pouches with twist-off caps could only be opened with difficulty because of the small caps and the difficulty in breaking seals, despite the substantially lower opening forces of 0.46 ± 0.06 Nm compared with the other torque closures. The evaluation of a package was found to be only partly dependent on the required opening force but strongly influenced by various design factors and consumer's expectations as well as experiences
An industry-oriented strategy for the finite element simulation of paperboard creasing and folding

The numerical simulation of paperboard creasing and folding processes is of increasing importance for the design and production of safe and reliable packaging systems. The extreme material anisotropy and the complexity of these processes require however simulation capabilities which are seldom available in commercial codes. Several approaches have been proposed in the literature over the years, in most cases making use of non‐linear material models developed ad hoc for this purpose. These models, some of which are very effective and accurate, are not in general available in commercial codes and are often based on the definition of a large number of parameters. In this paper, the possibility to obtain acceptable, first‐hand simulation results using only features already available in a commercial code is investigated. An advanced continuum constitutive model, recently presented in the literature, has been used as a reference for tuning the model and for assessing its accuracy. It is shown how standard features, usually available in state‐of‐the‐art commercial codes, can be employed to deal with the extreme material anisotropy, obtaining qualitatively good results in both the creasing and folding phases. The used standard model accounts for the extremely high anisotropy by means of embedded shell elements, playing the role of reinforcements in the fibre direction. The matrix is assumed to be isotropic and elastoplastic, with properties determined based on the behaviour in the thickness direction. The adopted plasticity model is a modified Drucker–Prager model with a cutoff on the tensile pressure side, available in the used commercial code. The procedure adopted for the identification of the small number of required material parameters is also discussed. Copyright © 2017 John Wiley & Sons, Ltd
Ice supersaturation in the ECMWF integrated forecast system

A parametrization for ice supersaturation is introduced into the ECMWF Integrated Forecast System (IFS), compatible with the cloud scheme that allows partial cloud coverage. It is based on the simple, but often justifiable, diagnostic assumption that the ice nucleation and subsequent depositional growth time-scales are short compared to the model time step, thus supersaturation is only permitted in the clear-sky portion of the grid cell.\ud
Results from model integrations using the new scheme are presented, which is demonstrated to increase upper-tropospheric humidity, decrease high-level cloud cover and, to a much lesser extent, cloud ice amounts, all as expected from simple arguments. Evaluation of the relative distribution of supersaturated humidity amounts shows good agreement with the observed climatology derived from in situ aircraft observations. With the new scheme, the global distribution of frequency of occurrence of supersaturated regions compares well with remotely sensed microwave limb sounder (MLS) data, with the most marked errors of underprediction occurring in regions where the model is known to underpredict deep convection. Finally, it is also demonstrated that the new scheme leads to improved predictions of permanent contrail cloud over southern England, which indirectly implies upper-tropospheric humidity fields are better represented for this region
A concept for a satellite mission to measure cloud ice water path and ice particle size

A passive satellite radiometer operating at submillimetre wavelengths can measure cloud ice water path (IWP), ice particle size, and cloud altitude. The paper first discusses the scientific background for such measurements. Formal scientific mission requirements are derived, based on this background and earlier assessments. The paper then presents a comprehensive prototype instrument and mission concept, and demonstrates that it meets the requirements. The instrument is a conically scanning 12-channel radiometer with channels between 183 and 664 GHz, proposed to fly in tandem with one of the Metop satellites. It can measure IWP with a relative accuracy of approximately 20% and a detection threshold of approximately 2 g/m². The median mass equivalent sphere diameter of the ice particles can be measured with an accuracy of approximately 30 μm, and the median IWP cloud altitude can be measured with an accuracy of approximately 300 m. All the above accuracies are median absolute error values; root mean square error values are approximately twice as high, due to rare outliers
Impact of airborne Doppler lidar observations on ECMWF forecasts

During the Atlantic THORPEX Regional Campaign (A-TReC) in autumn 2003, the airborne Doppler lidar of the Deutsches Zentrum f¨ur Luft- und Raumfahrt (DLR) was used to observe wind in predicted sensitive regions. In eight flights, the system measured a total of 1600 wind profiles that were experimentally assimilated in the global assimilation system at the European Centre for Medium-Range Weather Forecasts (ECMWF). The present study assesses the impact of these Doppler lidar measurements in Numerical Weather Prediction (NWP). It is shown that lidar observations have a significant impact on the analyses as well as on forecasts owing to high accuracy and spatial resolution. The measurements reduce the errors of the 1–4 day forecasts of geopotential height, wind, and humidity over Europe throughout the troposphere. On average, Doppler lidar measurements reduce the 2–4 day forecast error of geopotential height over Europe by 3%. This is a promising result, considering that observations have been gathered from only 28.5 flight hours. Dropsondes released in the same area as the Doppler lidar was operating show good agreement for measured winds, but smaller analysis impact and less reduction of the forecast error
Tropical Cyclogenesis Sensitivity to Environmental Parameters in Radiative-Convective Equilibrium

In this study, the relationship between the likelihood of tropical cyclogenesis and external environmental forcings is explored in the simplest idealized modelling framework possible: radiative-convective equilibrium on a doubly periodic f-plane. In such an environment, control of the equilibrium environmental sounding is reduced to three parameters: the sea-surface temperature, the Coriolis parameter, and the imposed background surface wind speed. Cloud-resolving mesoscale model simulations are used to generate environments of radiative-convective equilibrium determined by these three factors. The favourability of these environments for tropical cyclogenesis is measured in three ways: in terms of the maximum potential intensity (MPI) of the sounding, based on the thermodynamic theory of Emanuel; in terms of the ‘genesis potential’ determined by an empirical genesis parameter; and in terms of the propensity of weak initial vortices in these environments to form into tropical cyclones.

The simulated environments of radiative—convective equilibrium with no vertical wind shear are found to be very favourable for tropical cyclogenesis. Weak initial vortices always transition to a tropical cyclone, even for rather low sea-surface temperatures. However, the time required for these vortices to make the transition from a weak, mid-level vortex to a rapidly developing tropical cyclone decreases as the MPI increases, indicating the importance of MPI in enhancing the frequency of cyclogenesis. The relationship between this ‘time to genesis’ and the thermodynamic parameters is explored. The time to genesis is found to be very highly (negatively) correlated to MPI, with little or no relationship to convective instability, Coriolis parameter, mid-level humidity, or the empirical genesis parameter.

In some cases, tropical cyclones are found to form spontaneously from random convection. This formation is due to a cooperative interaction between large-scale moisture, long-wave radiation, and locally enhanced sea-surface fluxes, similar to the ‘aggregation’ of convection found in previous studies.National Science Foundation (U.S.) (Grant ATM-0432067
Assimilation of water vapour airborne lidar observations:\ud
Impact study on the COPS precipitation forecasts

The Convective and Orographically-driven Precipitation Study (COPS) carried out in summer 2007 over northeastern France and southwestern Germany provided a\ud
fairly comprehensive description of the low-troposphere water-vapour field, thanks in particular to the deployment of two airborne differential absorption lidar systems.\ud
These lidar observations were assimilated using the 3D-Var assimilation system of the Application of Research to Operations at MEsoscale (AROME) numerical\ud
weather prediction mesoscalemodel. The assimilation was carried out for the period 4 JulyÃ¢Â�Â�3 August by running a three-hour forward intermittent assimilation cycle.\ud
First, the impact of the lidar observations was assessed by comparing the analyses with a set of more than 200 independent soundings. The lidar observations were\ud
found to have a positive impact on the analyses by reducing the dry bias in the first 500 m above ground level and by diminishing the root-mean-square error\ud
by roughly 15% in the first km. Then the impact of the lidar observations was assessed by comparing the precipitation forecasts (obtained with and without the\ud
lidar observations for the period 15 JulyÃ¢Â�Â�2 August) with the gridded precipitation observations provided by the Vienna Enhanced Resolution Analysis. In general, the\ud
impact was found to be positive but not significant for the 24 h precipitation and positive and significant for the 6 h precipitation, with an improvement lasting up to\ud
24 h. Some selected case studies show that the improvement was obtained through a better depiction of convection initiation or through a more accurate positioning of\ud
the precipitation systems
Large-scale potential vorticity anomalies and deep convection

This is the accepted version of the following article: Russell, A., Vaughan, G. and Norton, E. G. (2012), Large-scale potential vorticity anomalies and deep convection. Q.J.R. Meteorol. Soc., 138: 1627–1639, which has been published in final form at http://onlinelibrary.wiley.com/doi/10.1002/qj.1875/abstract. Copyright @ 2012 Royal Meteorological Society.The effect on deep convection of large-scale potential vorticity (PV) anomalies and their associated tropospheric stable layers is complex and not well understood. This article examines the meteorological events of 9 July 2007 (IOP7b of the Convective and Orographically-induced Precipitation Study (COPS)), which was dominated by an upper-level PV anomaly that stretched from the UK to southern France and as far northeast as Denmark. Three precipitation regions were identified from the case: lines of intense storms beneath the PV anomaly; less intense, more widespread convective precipitation to the east of the PV anomaly; and, in between, a region of no precipitation. The latter of these coincided with the high-resolution measurements and model analyses from COPS. The extensive and varied data analyzed in this investigation show that convective available potential energy (CAPE) was present in this region (the distribution of CAPE and convective inhibition (CIN) is presented via an innovative, pseudo-3D visualization that allows horizontal and vertical interactions to be considered). However, convection was capped by a complex arrangement of dry layers; the base of the key layer was at 750 hPa. These dry layers descended separately from the upper troposphere, moving around the PV anomaly as it developed from a breaking Rossby wave to the west during the seven days before the IOP. This case adds to other studies that show that descent of complex dry layers is an important mechanism for forming convection-inhibiting atmospheric lids in Western Europe. A simple conceptual model is developed that synthesizes the effect of large-scale PV anomalies on deep convection from a series of consistent case studies. This model has significant implications for storm forecasting and projections of storminess in future climates, as it highlights the importance of thin structures that can advect hundreds of km before having an impact.NER
A ‘hurricane-like’ polar low fuelled by sensible heat flux:\ud
high-resolution numerical simulations

An unusually deep (961 hPa) hurricane-like polar low over the Barents Sea during 18–21 December 2002 is studied by a series of fine-mesh (3 km) experiments using the Weather Research and Forecasting (WRF) model. The simulated polar low was similar to hurricanes and similar previous case-studies in that it had a clear, calm and warm eye structure surrounded by moist convection organized in spiral cloud bands, and the highest surface wind speedswere found in the eye wall. The proximity to the sea ice and the high surface wind speeds (about 25ms−1) during the deepening\ud
stage triggered extremely high surface sensible and latent heat fluxes at the eye wall of about 1200 and 400 W m−2, respectively. As the polar low moved eastward and\ud
weakened, maximum surface sensible and latent heat fluxes dropped to about 600 and 300Wm−2, respectively. Two types of sensitivity experiments were designed to analyse the physical properties of the polar low. Firstly, physical processes such as condensational heating and sensible and/or latent heat fluxes were switched off–on throughout the simulation. In the second type, these processes were turned off–on after the polar low had reached its peak intensity, which minimized the deformation of the polar-low environment,making it suitable to study the direct effect of physical processes on themature vortex. The experiments suggest that the deepening stage of the polar low was dominated by baroclinic growth and that upper-level potential vorticity forcing contributed throughout its life cycle. After the deepening stage, the baroclinicity vanished and the polar low was fuelled by surface sensible heat fluxes while latent heat fluxes played a minor role. Condensational heating was not essential for the energetics of the polar low. Surprisingly, in experiments where\ud
condensational heating was turned off throughout the simulation, the polar low intensified
Relaxing the Tropics to an ‘observed’ state: analysis using a simple baroclinic model

The technique of relaxation of the tropical atmosphere towards an analysis in a month-season forecast model has previously been successfully exploited in a number of contexts. Here it is shown that when tropical relaxation is used to investigate the possible origin of the observed anomalies in June–July 2007, a simple dynamical model is able to reproduce the observed component of the pattern of anomalies given by an ensemble of ECMWF forecast runs. Following this result, the simple model is used for a range of experiments on time-scales of relaxation, variables and regions relaxed based on a control model run with equatorial heating in a zonal flow.\ud
\ud
A theory based on scale analysis for the large-scale tropics is used to interpret the results. Typical relationships between scales are determined from the basic equations, and for a specified diabatic heating a chain of deductions for determining the dependent variables is derived. Different critical time-scales are found for tropical relaxation of different dependent variables to be effective. Vorticity has the longest critical time-scale, typically 1.2 days. For temperature and divergence, the time-scales are 10 hours and 3 hours, respectively. However not all the tropical fields, in particular the vertical motion, are reproduced correctly by the model unless divergence is heavily damped. To obtain the correct extra-tropical fields, it is crucial to have the correct rotational flow in the subtropics to initiate the Rossby wave propagation from there. It is sufficient to relax vorticity or temperature on a time-scale comparable or less than their critical time-scales to obtain this. However if the divergent advection of vorticity is important in the Rossby Wave Source then strong relaxation of divergence is required to accurately represent the tropical forcing of Rossby waves