56 research outputs found

    Kvaliteta i dimenzijski parametri borove građe velikih dimenzija u svjetlu zahtjeva poljske pilanske industrije

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    Changes in the processing directions of round wood require the selection of raw material with appropriate quality and dimensional characteristics. In the case of large-size pine wood, these parameters translate significantly into its value and material indicators. The purpose of the research was to verify the currently applied classification principles with respect to the expectations of the market of wood industry customers. The research was conducted using the direct survey method, taking into account the structure of processing and sorting of production of wood industry representatives. The basic dimensional and quality groups for coniferous wood were separated, with wood defects assigned to them, in accordance with the currently binding principles of the quality and dimensional classification conducted by the State Forests. The respondents pointed out the necessity of changes in the minimum dimensions for wood of higher quality classes and changes in admissibility of selected defects in wood of lower classes.Promjene u načinu obrade trupaca zahtijevaju odabir sirovine odgovarajuće kvalitete i dimenzija. Kad je riječ o borovoj građi velikih dimenzija, ti parametri znatno utječu na njezinu vrijednost i materijalne pokazatelje. Cilj istraživanja bio je provjeriti trenutačno primjenjive pravilnike o klasifikaciji borove građe s obzirom na očekivanja tržišta drvne industrije. Istraživanje je provedeno metodom izravnoga anketnog ispitivanja predstavnika drvne industrije, pri čemu su uzeti u obzir struktura obrade proizvoda i način proizvodnje. Crnogorično je drvo razvrstano u osnovne dimenzijske i kvalitativne skupine kojima su pridodane greške drva, sukladno trenutačno obvezujućim pravilnicima o klasifikaciji drva prema kvaliteti i dimenzijama što ih provode Državne šume. Ispitanici su upozorili na nužnost promjene minimalnih dimenzija za drvo višeg razreda kvalitete te promjene glede dopuštenih grešaka drva nižeg razreda kvalitete

    Infectious Disease Risk Associated with Contaminated Propofol Anesthesia, 1989–2014

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    Administration of propofol, the most frequently used intravenous anesthetic worldwide, has been associated with several iatrogenic infections despite its relative safety. Little is known regarding the global epidemiology of propofol-related outbreaks and the effectiveness of existing preventive strategies. In this overview of the evidence of propofol as a source of infection and appraisal of preventive strategies, we identified 58 studies through a literature search in PubMed, Embase, and Lilacs for propofol-related infections during 1989–2014. Twenty propofol-related outbreaks have been reported, affecting 144 patients and resulting in 10 deaths. Related factors included reuse of syringes for multiple patients and prolonged exposure to the environment when vials were left open. The addition of antimicrobial drugs to the emulsion has been instituted in some countries, but outbreaks have still occurred. There remains a lack of comprehensive information on the effectiveness of measures to prevent future outbreaks

    Neurofeedback training for peak performance

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    Aim. One of the applications of the Neurofeedback methodology is peak performance in sport. The protocols of the neurofeedback are usually based on an assessment of the spectral parameters of spontaneous EEG in resting state conditions. The aim of the paper was to study whether the intensive neurofeedback training of a well-functioning Olympic athlete who has lost his performance confidence after injury in sport, could change the brain functioning reflected in changes in spontaneous EEG and event related potentials (ERPs). Case study. The case is presented of an Olympic athlete who has lost his performance confidence after injury in sport. He wanted to resume his activities by means of neurofeedback training. His QEEG/ERP parameters were assessed before and after 4 intensive sessions of neurotherapy. Dramatic and statistically significant changes that could not be explained by error measurement were observed in the patient. Conclusion. Neurofeedback training in the subject under study increased the amplitude of the monitoring component of ERPs generated in the anterior cingulate cortex, accompanied by an increase in beta activity over the medial prefrontal cortex. Taking these changes together, it can be concluded that that even a few sessions of neurofeedback in a high performance brain can significantly activate the prefrontal cortical areas associated with increasing confidence in sport performance

    Neuromarkers of anxiety and depression in a patient after neuro-ophthalmic surgery of the meningioma : effect of individually-tailored tDCS and neurofeedback

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    The aim of the study was to evaluate the effectiveness of individually tailored anodal tDCs/ neurofeedback protocol for the reduction of post-operative depression after a neuroophtalmological operation of the meningioma. The neuromarkers in Quantitative EEG (QEEG) and Event-related potentials (ERPs) were utilized in the construction of protocol and evaluation. [b]Case description[/b]. A 45-year-old female after successful neuro-ophthalmic surgery of the meningioma, complained of severe pain and anxiety, difficulties with sleeping, attention and memory problems, as well as inability to continue working in her given profession. Neuropsychological testing showed lack of cognitive disturbances and post-operative depression. Two working hypotheses were tested to find neuromarkers of depression and anxiety. In line with the ‘depression hypothesis’ a frontal alpha asymmetry pattern was found in the patient, and in line with the ‘anxiety’ hypothesis an increased left temporal P1 wave in response to visual stimuli was found in ERPs. A specific alpha asymmetry neurofeedback protocol combined with an anodal tDCS was suggested. Twenty sessions of individually-tailored anodal tDCs/ neurofeedback protocol were performed. The QEEG frontal asymmetry pattern and the excessive temporal P1 wave were normalized after the intervention. [b]Conclusions. [/b]The patient recovered from post-operative depression and returned to work after 20 sessions of the combined neurofeedback/tDCS protocol. Specific patterns of QEEG and ERPs serve as neuromarkers for constructing the protocol and for monitoring the results of intervention

    Neuromarkers of anxiety and depression in a patient after neuro-ophthalmic surgery of the meningioma – effect of individually-tailored tDCS and neurofeedback

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    The aim of the study was to evaluate the effectiveness of individually tailored anodal tDCs/ neurofeedback protocol for the reduction of post-operative depression after a neuroophtalmological operation of the meningioma. The neuromarkers in Quantitative EEG (QEEG) and Event-related potentials (ERPs) were utilized in the construction of protocol and evaluation. [b]Case description[/b]. A 45-year-old female after successful neuro-ophthalmic surgery of the meningioma, complained of severe pain and anxiety, difficulties with sleeping, attention and memory problems, as well as inability to continue working in her given profession. Neuropsychological testing showed lack of cognitive disturbances and post-operative depression. Two working hypotheses were tested to find neuromarkers of depression and anxiety. In line with the ‘depression hypothesis’ a frontal alpha asymmetry pattern was found in the patient, and in line with the ‘anxiety’ hypothesis an increased left temporal P1 wave in response to visual stimuli was found in ERPs. A specific alpha asymmetry neurofeedback protocol combined with an anodal tDCS was suggested. Twenty sessions of individually-tailored anodal tDCs/ neurofeedback protocol were performed. The QEEG frontal asymmetry pattern and the excessive temporal P1 wave were normalized after the intervention. [b]Conclusions. [/b]The patient recovered from post-operative depression and returned to work after 20 sessions of the combined neurofeedback/tDCS protocol. Specific patterns of QEEG and ERPs serve as neuromarkers for constructing the protocol and for monitoring the results of intervention

    Effect of sawn zone on the quality of lumber in the evaluation of selected pine wood defects

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    Effect of sawn zone on the quality of lumber in the evaluation of selected pine wood defects. In the course of research on the sawn pine raw material with defined distribution of the defects, a variable level of change in the presence of knots was assessed. Initially, the experimental material was classified in terms of the general-purpose timber, and then the strength classes of wood for structural applications were assigned. The proportion of sound knots increased in case of wood obtained from the middle and top zones. In the case of buttend logs, an increase in the share of the rotten knots having an average diameter of 2-4 cm was observed. The intensity of the defect’s occurrence corresponded with the zone of origin along the large-sized roundwood length.Wpływ strefy przetarcia na jakość tarcicy w ocenie wybranych wad drewna sosnowego. W trakcie badań na surowcu tartacznym sosnowym o określonym rozkładzie wad oceniono zmienny poziom występowania sęków. Początkowo materiał doświadczalny sklasyfikowano w kategoriach tarcicy ogólnego przeznaczenia, a następnie przypisano klasy wytrzymałościowe drewna do zastosowań konstrukcyjnych. Udział sęków zdrowych wzrósł w przypadku drewna pozyskanego ze strefy środkowej i górnej. W przypadku kłód odziomkowych zaobserwowano wzrost udziału sęków zepsutych o średniej średnicy 2-4 cm. Intensywność występowania wady tarcicy odpowiadała lokalizacji strefy jej pochodzenia na długości wielkowymiarowej drewna okrągłego

    Influence of qualitative and dimensional classification of Pinewood raw material as an efficiency indicator in the production of selected timber assortments

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    Wood processing plants in Poland are recipients of more than 50% of round wood, which is delivered by the State Forests National Forest Holding. Thus playing a crucial role in the technological processing of raw material for all other wood industry branches. Each group of recipients has individual needs and expectations concerning the quality of the raw material such as, its type and the size of the cross-sections of the assortment used for further production. Therefore, it is economically justified for small production plants to abandon the production of narrow groups of assortments, which usually meets the standards of timber for general purposes. The aim is to make wood processing more flexible and lower the quality of raw material to produce assortments for a specific branches of the wood industry. Wood processing experiments were conducted to produce laths for construction purposes. These materials are one of the most important elements of roof constructions. The research proved empirically that it was possible to produce quality class 1 laths (88% of all laths produced) from WC0 class pinewood used as the input raw material and that the quantitative efficiency exceeded 55%.Wpływ doboru jakościowo wymiarowego surowca sosnowego, jako wskaźnik wydajnościowy w produkcji wybranych sortymentów tarcicy. Zakłady pierwiastkowego przerobu drewna w Polsce są odbiorcami ponad 50% drewna w postaci okrągłej, sprzedawanego przez Państwowe Gospodarstwo Leśne „Lasy Państwowe”. Tym samym odgrywają decydującą rolę na drodze technologicznego przetworzenia surowca dla pozostałych gałęzi przemysłu drzewnego. Każda z grup odbiorców posiada indywidualne potrzeby dotyczące jakości wykorzystywanego surowca, gatunku oraz wielkości przekrojów poprzecznych sortymentu wykorzystywanych do własnej dalszej produkcji. Stąd ekonomicznie uzasadnione jest, odchodzenie mały zakładów produkcyjnych od wytwarzania wąskich grup sortymentów, często zgodnych z normami tarcicy tartacznej ogólnego przeznaczenia. Dąży się do uelastycznienia przerobów i wytwarzanie sortymentów pod konkretną gałąź przemysłu z surowca niższej jakości. Dla celów badawczych przeprowadzone zostały przeroby doświadczalne uwzględniające pozyskanie łat budowlanych. Są to materiały, będące jednym z ważniejszych elementów konstrukcji dachowych. Doświadczalnie oraz empirycznie udowodnione zostało, że w odniesieniu do surowca wejściowego, jakim jest drewno sosnowe klasy WC0, możliwe jest wytwarzanie łat zaklasyfikowanych do I klasy jakości (stanowiącej 88% z wszystkich wytworzonych łat) z wydajnością ilościową przekraczającą 55%

    Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum

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    Properties of fiber-gypsum composite formed on the basis of hemp (Cannabis sativa L.) fibers grown in Poland and natural gypsum. The popularity of composites reinforced with natural fibers is constantly growing and therefore, they are a subject of many scientific works as well. An example of interesting concept is the use of hemp fibers to reinforce a gypsum matrix and therefore, presented study was aimed to determine the effect of their content on the properties of resultant composites. Moreover, the influence of setting temperature was also investigated. The scope of the research included determination of properties such as: density, setting time, bending strength, modulus of elasticity and thermal conductivity coefficient. Studies have shown that as the amount introduced fibers increases, the density of manufactured composites decreases. Furthermore, increase in the content of hemp causes a significant extension in setting time of the gypsum matrix. Based on the outcomes of mechanical properties, it was found that the optimal content of fibers is 4% and further increase in their share results in a deterioration of flexural strength characteristics. The increase in a setting temperature leads to the reduction in their bending strength and modulus of elasticity. Composites reinforced with hemp fibers demonstrate significantly improved thermal insulation propertiesWłaściwości kompozytów włóknisto-gipsowych powstałych na bazie włókien konopi siewnej (Cannabies sativa L.) uprawianych w Polsce i gipsu naturalnego. Popularność kompozytów wzmacnianych włóknami naturalnymi nieprzerwanie rośnie, co sprawia, że są one przedmiotem wielu badań naukowych. Przykładem interesującej koncepcji jest wykorzystanie włókien konopi siewnej w celu wzmocnienia płyt gipsowych. A zatem, przeprowadzone zostały badania dotyczące wpływu ilości dodawanych włókien konopnych oraz temperatury sieciowania wzmocnionej matrycy na właściwości wytworzonych kompozytów gipsowych. Zakres przeprowadzonych eksperymentów obejmował określenie gęstości, czasu sieciowania, wytrzymałości na zginanie, modułu sprężystości oraz współczynnika przewodzenia ciepła. Badania wykazały, iż wraz ze wzrostem udziału włókien czas sieciowania matrycy znacznie się wydłuża, a gęstość otrzymywanych kompozytów maleje. Wykazano również, iż optymalną ilością wzmocnienia konopnego zapewniającą najlepsze właściwości wytrzymałościowe jest 4%, a dalsze zwiększenie jego udziału powoduje znaczne pogorszenie wytrzymałości. Ponadto zwiększenie temperatury podczas sieciowania wpływa negatywnie na charakterystykę wytrzymałościową wyprodukowanych płyt. Właściwości izolacyjne ulegały natomiast znacznej poprawie wraz z rosnącym udziałem włókien konopnych w płycie gipsowej
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