Spatial Learning and Action Planning in a Prefrontal Cortical Network Model

The interplay between hippocampus and prefrontal cortex (PFC) is fundamental to spatial cognition. Complementing hippocampal place coding, prefrontal representations provide more abstract and hierarchically organized memories suitable for decision making. We model a prefrontal network mediating distributed information processing for spatial learning and action planning. Specific connectivity and synaptic adaptation principles shape the recurrent dynamics of the network arranged in cortical minicolumns. We show how the PFC columnar organization is suitable for learning sparse topological-metrical representations from redundant hippocampal inputs. The recurrent nature of the network supports multilevel spatial processing, allowing structural features of the environment to be encoded. An activation diffusion mechanism spreads the neural activity through the column population leading to trajectory planning. The model provides a functional framework for interpreting the activity of PFC neurons recorded during navigation tasks. We illustrate the link from single unit activity to behavioral responses. The results suggest plausible neural mechanisms subserving the cognitive “insight” capability originally attributed to rodents by Tolman & Honzik. Our time course analysis of neural responses shows how the interaction between hippocampus and PFC can yield the encoding of manifold information pertinent to spatial planning, including prospective coding and distance-to-goal correlates

Drilling large diameter intake wells with cutter bits in loose and weakly consolidated rocks

Most of the useful aquifers in Poland occur in the Quaternary and Tertiary horizons, which are deposited at a depth of tens to hundreds of meters. Owing to the need of providing large quantities of water for municipal and industrial purposes, the aquifers are more and more frequently opened with large diameter wells of various designs. Such wells are mostly drilled with the rotary method with reverse mud circulation with the use of various bits. The Quaternary and Tertiary strata abound in loose and weakly consolidated rocks therefore cutter bits are predominantly used. They allow for high rates of drilling and shorter time of drilling of the well. This significantly influences the negative influence of drilling mud on the near screen zone of the aquifer and better hydraulic properties of the well. Drillability tests were performed with cutter bits of 0.86 and 0.67 m diameter for providing high rates of drilling of large diameter intake wells in loose and weakly consolidated rocks. The research was made for measurement sections 0.5 to 1.0 m long, and each of them was drilled at con- stant rotational velocity and axial weight on bit. Prior to the drillability tests the limitation of weight on bit and rotational velocity of bit imposed by the technical characteristic of Prakla B50 rig, strength of the string and butter bit were established. Various regression models were analyzed for the sake of finding a dependence between drilling rate and axial weight on bit and rotational velocity of bit for particular macroscopically homogeneous layers. The best results were obtained for the exponent model illustrating the influence of axial weight on bit and rotational velocity of bit on the drilling rate, which has been proved by the calculated regression coefficients and statistical parameters

Environmental pollution with oil-products in the refinery area

Niekontrolowane wycieki węglowodorów są istotną ingerencją w środowisko gruntowe. Hamują one wymianę gazową, ograniczają dostęp światła, zmniejszają stężenie rozpuszczonego tlenu, zanieczyszczają glebę i grunty, zaburzają homeostazę, a przede wszystkim mają działanie toksyczne, mutagenne i kancerogenne na wszystkie organizmy żywe. W artykule przedstawiono wyniki badań stanu jakościowego środowiska gruntowego w rejonie instalacji petrochemicznych w zakresie zawartości w nich węglowodorów. Na podstawie porównania wyników badań geochemicznych do wartości progowych zawartych w rozporządzeniu Ministra Środowiska dotyczących standardów jakości gleby i ziemi stwierdzono, że gleby i grunty na terenach rafineryjnych są zanieczyszczone substancjami ropopochodnymi ponad dopuszczalne wartości, co kwalifikuje je do oczyszczania.Uncontrolled seepages of hydrocarbons significantly affect the ground environment. They hinder gaseous exchange, limit access of the light, reduce concentration of dissolved oxygen, contaminated the soil and ground, disturb homeostasis, and before all - are toxic, mutagenic and cancerous to all living organisms. The results of analyses of the qualitative state of ground environment in the area of petrochemic installations on hydrocarbon content are presented in the paper. Basing on the comparison of geochemical analyses and threshold values in the Regulation about soil and ground standards of the Minister of Environment it was stated that soils and grounds in the refinery areas were polluted with oil-products. The admissible concentrations were exceeded, and thus the grounds were qualified to the treatment programs

Analysis of changes in groundwater chemistry near industrial landfills

Odpady przemysłowe charakteryzują się stosunkowo dużą uciążliwością dla środowiska. Dotyczy to głównie odpadów powstających w przemyśle chemicznym, a zwłaszcza tych, które powstają przy produkcji nawozów azotowych i tworzyw sztucznych. Odpady te zawierają znaczne ilości wymywalnych składników zarówno organicznych jak i nieorganicznych. Odcieki infiltrujące do wód podziemnych z nieuszczelnionych lub źle uszczelnionych składowisk odpadów zawierają duże ilości związków amonowych, arsenu, chromu, ołowiu, miedzi, cynku, żelaza oraz związków organicznych. W artykule przedstawiono wyniki prowadzonego monitoringu wód podziemnych w rejonie ocenianego składowiska odpadów oraz pokazano trendy zmian ich jakości. Otrzymane wyniki mogą być podstawą do podejmowania dalszych działań dotyczących ograniczenia negatywnego wpływu składowiska na wody podziemne i powierzchniowe.Industrial waste is environmentally noxious. This mainly refers to waste produced by chemical industry, mainly phosphatic fertilizers and plastics. Such waste contains considerable amounts of washable organic and inorganic components. Seepages penetrating the groundwaters from untight or badly sealed landfills contain ammonia, arsenic, chromium, lead, copper, zinc, iron and organic compounds. The results of groundwater monitoring of groundwaters near the analyzed landfill show their qualitative changes and the measures for improving it. The obtained results can be a basis for further decisions regarding the reduction of the negative impact of the landfill on groundwaters and surface waters

Drilling large diameter water wells in carbonate strata in the Lublin area

One of the most important sources of water for communal purposes in the Lublin area are the useful groundwater aquifers intaken with deep drilled wells. Such wells should be highly efficient and localized in a close vicinity of the local water supply network to lower the cost of transport. Large amounts of water can be produced by large diameter wells, where heavy duty pump aggregates can be installed. High rates of penetration cannot be obtained if the profile abounds in hardly drillable carbonate. This elongates the time of drilling and increases negative impact of mud on the near well zone of the aquifer. It also lowers hydraulic parameters of the well. To improve the efficiency of the wells, drillability tests with cogged bits were performed in carbonate rocks to optimize the mechanical parameters of drilling. Measurement sections, each 0.3 to 0.5 m long, were selected for the tests. Each section was drilled at constant rotational speed and weight of bit values. Prior to the drillability tests, the limits on the weight of bit and rotational speed of the bit were established, in line with the technological characteristic of rig Wirth B3A, strength of the string and of the cogged bit

Efficiency of drilling large diameter wells with cutter bits on Szczerców opencast

Drilling of large diameter wells to be used for dewatering of lignite deposits is inefficient due to the presence of large packages of loose Quaternary and Tertiary strata. Moreover, considerable dewatering of the rock mass favors serious complications and drilling break-downs connected with the sliding of wellbore walls. Accordingly, new technical and technological solutions, which enable faster drilling, are searched for. In this way the time of operation of drilling mud on the near-wellbore zone can be shortened and the safety of drilling works increased. For the sake of obtaining higher rates of drilling in large diameter dewatering wellbores a new cutter bit 0.96 m of diameter was designed. Drillability tests in industrial conditions followed. These tests were performed in separated, loose and low-compaction, macroscopically homogeneous rocks of similar drillability. The tests were performed on selected sections 0.3 to 1.0 m long, and each of the sections was drilled at constant rotational velocity and weight on bit. Prior to these tests there were established limitations regarding weight on bit and rotational velocity of the bit, in reference to the technical characteristic of the rig, strength of the string and the cutter bit. Two different regression models were considered to find a dependence of mechanical drilling rate on weight on bit and rotational velocity of the bit for selected macroscopically homogeneous strata. The most favorable results were obtained for a power model representing impact of axial stress and rotational velocity of the bit on the drilling rate. They have been confirmed by calculated regression coefficients and statistical parameters. Industrial tests were performed to assess the efficiency of drilling large diameter dewatering wells with a cutter bit of 0.96 m diameter on the basis of the presented model of average drilling rate. The results for the average drilling rate turned out to be much higher than the ones obtained so far

Evaluation of the state of ground environment in the area of oil storing and regeneration systems

W obrębie instalacji do magazynowania i regeneracji olejów przepracowanych często dochodzi do zanieczyszczenia środowiska gruntowego różnego rodzaju węglowodorami ropopochodnymi. Zanieczyszczenie to może być spowodowane zarówno rozszczelnieniem istniejących instalacji przemysłowych, zbiorników magazynowych jak i instalacji do rozładunku cystern oraz ich napełniania zregenerowanymi olejami. W artykule przedstawiono wyniki badań stanu jakościowego gruntów w zakresie zawartości węglowodorów alifatycznych i aromatycznych na terenie jednej z istniejących w kraju instalacji do magazynowania i regeneracji olejów przepracowanych. Porównując otrzymane wyniki badań chemicznych próbek gruntów do obowiązujących aktualnie standardów jakościowych środowiska gruntowego stwierdzono, że jest ono znacznie zanieczyszczone substancjami węglowodorowymi i wymaga oczyszczenia. Uwzględniając istniejące w rejonie badań warunki geologiczne zaproponowano efektywną metodę oczyszczania środowiska gruntowego.Ground environmental contaminations with hydrocarbon oil-products are frequently encountered within the oil storing and regeneration systems. Such contaminations can be caused both by untight installations of industrial storages as well as systems for loading and unloading cisterns with treated oils. The results of analyses of aliphatic and aromatic hydrocarbons content in grounds of one of the existing Polish installations for treating waste oils are presented in the paper. The comparison of the results of chemical analyses and the environmental standards reveals that the ground is polluted with hydrocarbons and thus needs remediation

Qualitative analysis of groundwaters in the area of waste landfill "Za Białą"

Składowiska odpadów wytwarzanych w przemyśle chemicznym i energetyce wywierają bardzo silny i różnorodny wpływ na wszystkie elementy środowiska naturalnego. Ich negatywne oddziaływanie szczególnie dotyczy środowiska gruntowo-wodnego, zwłaszcza w przypadku nieuszczelnionych lub źle uszczelnionych składowisk odpadów. Powstające w złożu odpadów toksyczne odcieki bezpośrednio infiltrują do wód podziemnych i powierzchniowych. W artykule przedstawiono wyniki badań laboratoryjnych wód podziemnych w rejonie składowiska "Za Białą" i na podstawie analizy zmian koncentracji wybranych wskaźników pokazano trendy zmian jakości wód odpływających z omawianego rejonu.Landfills contaning waste produced by the chemical and energy industry exert a very strong impact on all elements of natural environment. Their negative influence concentrates on ground and water environment, especially in the case of unsealed or badly sealed landfills. Toxic seepages infiltrating ground- and surface waters are formed. The results of laboratory analyses of groundwaters in the area of landfill "Za Białą" as well as the analyses of concentrations of selected parameters revealed quality trends of waters outflowing from the discussed area