Harvesting tools and the spread of the Neolithic into the Central-Western Mediterranean area

This paper discusses the current state of research on harvesting technologies of the first farming communities of the central and western Mediterranean area between ca. 6000–5900 cal BC and 4800–4700 cal BC. New data obtained from the analysis of almost 40 sites from the Italian Peninsula is compared with data previously collected from the Iberian Peninsula and southern France. Results indicate the existence of at least two different harvesting traditions, one characterized by curved sickles used for harvesting at a low or middle height; the other characterized by reaping knives with parallel hafted blades, probably mainly used for ear harvesting. Processes of innovation and change have been highlighted, suggesting that harvesting techniques changed and evolved through time. Besides, the mechanism and pace of diffusion of curved sickles have been explored, too

Harvest time: Crop-reaping technologies and the Neolithisation of the Central Mediterranean

Neolithic societies were defined by the development of agricultural economies not only because part of their diet was obtained from cultivated plants, but also because crophusbandry practices strongly affected people’s lifestyles in a variety of ways. It is therefore unsurprising that the development and diffusion of agriculture can be studied from diverse perspectives and with different approaches, by analysing, for example, the macro- and micro-botanical remains of fruits and grains for morphometric and taxonomic variation (Colledge & Conolly 2007) and genetic history (Mascher et al. 2016). Conversely, agriculture can be indirectly assessed through its impact on the environment and subsequent landscape modifications (Zanchetta et al. 2013; Mercuri 2014). Yet another approach explores crop-husbandry practices as reflected in changing technology. New agricultural tasks required the adaptation of existing technologies and the adoption of new tools and practices, including querns, millstones and other grain-grinding equipment, as well as artefacts and structures for grain storage, cooking and processing. The most evident innovation in flaked stone technology associated with the Neolithisation phenomenon concerns the so-called ‘glossy blades’. Early experimental and use-wear studies of these blades fed debate about the mechanisms responsible for polish formation (Anderson 1982; Unger-Hamilton 1984). More recently, however, renewed attention towards these tools and their technological, functional and geographic variability (Ibáñez et al. 2008; Maeda et al. 2016) has considered their significance in relation to economic organisation, cultural boundaries and processes of technological innovation

Cooperative distributed model predictive control,

Abstract In this paper we propose a cooperative distributed linear model predictive control strategy applicable to any finite number of subsystems with the following features: hard input constraints are satisfied; the distributed control provides nominal stability for the same set of plants as centralized control; terminating the iteration of the distributed controllers prior to convergence retains closed-loop stability; in the limit of iterating to convergence, the control is plantwide Pareto optimal and equivalent to the centralized control solution; no coordination layer is employed. We first prove exponential stability of suboptimal model predictive control and show the proposed cooperative control strategy is in this class. We also establish that under perturbation from a stable state estimator, the origin remains exponentially stable. For plants with sparsely coupled input constraints, we provide an extension in which the decision variable space of each suboptimization is augmented to achieve Pareto optimality. We conclude with a simple example showing the performance advantage of cooperative control compared to noncooperative and decentralized control strategies

A Candidate to Replace PID Control: SISO Constrained LQ control

It is commonly believed that for single-input/single-output (SISO) systems, well-tuned proportional, integral, derivative (PID) controllers work as well as model-based controllers and that PID controllers are more robust to model errors. In this paper we present a novel offset-free constrained linear quadratic (LQ) controller for SISO systems, which is implemented in an efficient way so that the total controller execution time is similar to that of a PID. The proposed controller has three modules: a state and disturbance estimator, a target calculation, and a constrained dynamic optimization. It is shown that the proposed controller outperforms PID both in setpoint changes and disturbance rejection, it is robust to model errors, it is insensitive to measurement noise, and it handles constraints better than common anti-windup PID. Tuning the proposed controller is simple. In principle there are three tuning parameters to choose, but in all examples presented only one was actually varied, obtaining a clear and intuitive effect on the closed-loop performance. © 2005 American Institute of Chemical Engineers

New phosphazene-based chain extenders containing allyl and epoxide groups

In this paper we present the synthesis and the characterization of cyclophosphazenes substituted with allyl groups, their transformation in epoxide-containing cyclophosphazenes and the final utilization of these compounds as chain extenders in combination with polyamides. The reaction at high temperature of Nylon-6 with epoxy-functionalized cyclophosphazenes leads to the opening of the epoxy units by the action of both amino (-NH2) and carboxylic (-COOH) end-groups of the polymer to enhance the final molecular weight of this material. The consequences of this fact on the thermal, mechanical and visco-elastic properties of treated Nylon-6 have been also evaluated and compared to those of the pristine material. Possible utilization of these cyclophosphazenes in recycling processes for degraded polyamides could be envisaged