Programming and proving with classical types

The propositions-as-types correspondence is ordinarily presen- ted as linking the metatheory of typed λ-calculi and the proof theory of intuitionistic logic. Griffin observed that this correspondence could be extended to classical logic through the use of control operators. This observation set off a flurry of further research, leading to the development of Parigot’s λμ-calculus. In this work, we use the λμ-calculus as the foundation for a system of proof terms for classical first-order logic. In particular, we define an extended call-by-value λμ-calculus with a type system in correspondence with full classical logic. We extend the language with polymorphic types, add a host of data types in ‘direct style’, and prove several metatheoretical properties. All of our proofs and definitions are mechanised in Isabelle/HOL, and we automatically obtain an inter- preter for a system of proof terms cum programming language—called μML—using Isabelle’s code generation mechanism. Atop our proof terms, we build a prototype LCF-style interactive theorem prover—called μTP— for classical first-order logic, capable of synthesising μML programs from completed tactic-driven proofs. We present example closed μML programs with classical tautologies for types, including some inexpressible as closed programs in the original λμ-calculus, and some example tactic-driven μTP proofs of classical tautologies

RESEARCHES ON THE DEVELOPMENT OF AN EXPERIMENTAL MODEL OF WET SATURATED STEAM DISTILLATION EQUIPMENT

Distillation is a conventional method of extracting volatile oils from medicinal and aromatic plants. This is defined as a process of separating the components of a mixture that is based on the difference between the vaporization temperatures of the constituents, respectively water and oil when distilling medicinal plants. Distillation can be performed in three ways: distillation with water, by boiling the mixture of plants and water, condensation of resulting vapours and separation of oil, distillation with water and steam, in which the steam obtained by evaporating a quantity of water passes through the plant batch; steam distillation under pressure provided by an external generator, a process named in the literature and steam entrainment. The steam distillation process is applicable to many medicinal and aromatic plants that grow in our country. The extraction of volatile oils through this process depends on the different characteristics of the plants but also on the main parameters of the process, pressure and temperature, which are different

RESEARCHES ON THE DEVELOPMENT OF AN EXPERIMENTAL MODEL OF FISH POND FOR INTENSIVE FISH FARMING IN POLYCULTURE SYSTEM

In Romania, the fisheries and aquaculture sectors face several challenges. These mainly involve increasing competitiveness for the production and processing sectors. Polyculture is the breeding of several species of fish in the same space (pond, lakes, etc.). It has advantages: better capitalization of trophic potential, diversified assortment for consumers, increased production with the same human and financial effort and disadvantages: competition between species, the need for additional labour in harvest fishing, additional warehouses for parking fish. Polyculture is recommended in lakes, ponds and some ponds for extensive, semi-intensive and sometimes intensive production

INTELLIGENT WIRELESS TECHNOLOGY USAGE EFFECT IN CONTEXT OF PHYTOSANITARY TREATMENT SPRAYING

In agriculture, pesticides and fertilizers are applied to prevent crop disease and increase plant productivity. As a result of the digitalization of agriculture, human labor is increasingly interacting with intelligent technology through robots to facilitate agricultural operations. The use of intelligent technology protects the natural ecosystem by reducing the major damage caused by the unconventional application of phytosanitary treatments resulting in a flexible, proportional spraying at precise angles, thus avoiding the generation of large amounts of chemicals. This paper presents a short review about the state of the art of wireless sensors networks and how together with robotics can be applied in different fields of agriculture through the prism of sprayers that include a detection system and a wireless controlled spraye

CONSIDERATIONS CONCERNING THE AUTOMATION OF PROTECTED SPACES

In the last period there is an intensification of the researches oriented towards the automation of the specific activities of the horticultural production in protected spaces. The greenhouses offer a shelter in which a microclimate suitable for plants is maintained, which is obtained by regulating / adjusting the heat and the amount of light coming from the sun, by means of actuation systems (actuators-technical devices that generate an action to reach a specific objective). The paper presents a brief communication on the main drive systems used in greenhouses: ventilation and cooling systems; heating systems; irrigation systems, whose drive systems are mainly composed of electrical devices, especially electric motors or pump

TECHNOLOGY FOR ORGANIC WEED CONTROL

In recent years, crop maintenance works have become a major challenge for organic farming systems, where the application of chemical treatments is totally forbidden. The effect of weeds on crops varies according to pedoclimatic, biological or technological parameters, the resulting damages being both quantitative and qualitative. By weed control, we aim to prevent their competition in order to obtain maximum crop yields.Among the methods of thermal weed control, used as an alternative to chemical weeding, steam or hot water-based ones have been increasingly used as they provide an efficient, environmentally friendly and economical way of removing harmful plants.This paper presents a technology for the maintenance of medicinal and aromatic plant organic crops, based on the use of innovative equipment for weed thermal control by using hot water

A REAL-TIME MONITORING APPLICATION OF ENVIRONMENTAL CONDITIONS IN PROTECTED AREAS

With the development of technology, the greenhouse sector is constantly expanding, which is advantageous in terms of material economy, cost reduction, improved lighting efficiency and cultivation, but at the same time requires the implementation of a large number of sensor nodes to ensure coverage of environmental monitoring. The paper presents a real-time monitoring application of environmental conditions in a greenhouse, which includes sensors for monitoring temperature, relative humidity; CO2 concentration; soil temperature (at 3 depths: ground level, 10, 20 cm)

STUDY ON THE CONVERSION OF A CONVENTIONAL TRACTOR INTO AN ELECTRIC TRACTOR

The paper presents the study on how a classic tractor with internal combustion engine can be modified so that it is powered by a battery-powered electric motor. The article presents equipment and components with which a tractor can be modified so that it can run on electricity. In general, an electric tractor consists of the chassis from which the heat engine, electric motor, battery, control and configuration equipment, software used and communication equipment, of the electronic systems on board the tractor are removed

GENERAL ASPECTS REGARDING THE GROWTH FRESHWATER FISH IN CUBES, AN ALTERNATIVE FOR AQUACULTURE IN ROMANIA

Due to the increased consumption of fish, as an alternative to achieving healthy population nutrition, the development of European aquaculture also shows an increasing trend. At present, freshwater culture is about 42% of total European fish production. Valuable species, from an economic point of view, can be reared in intensive systems in cages on running waters or ponds, combined with less valuable species. There are also new species that are gradually becoming increasingly important for the fish industry in Europe. Freshwater aquaculture in Romania is based on rainbow trout and carp which are still predominant species, but there is significant demand for valuable fish species [11,12,16]. Â

SEPARATION OF CHOPPED NETTLE MATERIAL ON PLANE SIEVE LENGTH

The paper presents the results of several experimental researches regarding to a separation mixture of dried and chopped nettle fragments on a dimensional separator of medicinal plants, equipped with oscillating flat sieves. Three parameters were varied (material flow rate, sieves angle of inclination and oscillations sieves frequency). For separation process description along chopped vegetal material sieves, the experimental results have been tested by Rosin-Rammler distribution law