Modelling of ecological status of Polish lakes using deep learning techniques

Environmental Science and Pollution Research - Since 2000, after the Water Framework Directive came into force, aquatic ecosystems’ bioassessment has acquired immense practical importance for...     

Musculoskeletal Load Assessment of the Upper Limb Positions Subjectively Chosen as the Most Convenient

Work posture is determined by interdependence between work stand design, the necessity to perform given activities, and the anthropometric dimensions of the worker, but it also depends on individual preferences. The aim of the study was to compare the musculoskeletal load of the right upper extremity under conditions of imposed (standard) upper limb position and subjectively chosen ones, and to assess the influence of the changes in magnitude of the external force on the musculoskeletal load in the examined limb positions. Ten healthy male participants took part in the study. Muscular load associated with different upper extremity positions with and without external load were assessed. Musculoskeletal load for standard and subjectively chosen limb positions and two different values of external load were compared by means of theoretical and experimental methods. Results indicate that differences in musculoskeletal load between imposed and subjectively chosen limb positions were not high enough to show statistically significant differences, and the upper limb position chosen by the participant does not always cause the lowest musculoskeletal load.     

Circadian Rhythm of Heart Rate,Urinary Cortisol Excretion,and Sleep in Civil Air Traffic Controllers

The examination of Air Traffic Controllers (ATCs) from the Warsaw Airport (Poland) included 24-hr ECG monitoring. The participants were 10 civil ATCs, 9 males and 1 woman. The study was carried out on a group of 19 ATCs during their duty periods, 14 of them working 12-hr shifts and 5 performing 24-hr duties. The participants collected urine every 4 hrs, and Cortisol concentration was determined. Further, the survey included the quality and duration of sleep, and subjective fatigue in the 62 participants.

In ATCs, shift work modifies natural rhythms of the circulatory system and decreases the ability for intensified mental work at night. In consequence ATCs experience frequent sleep disorders.     

Methods of Assessing Efficiency of UV-Protecting Products

A few aspects of skin protection against ultraviolet (UV) light and methods of assessing efficacy of UV-protecting cream or gels have been discussed. UV-protection in cream and gels is not only a strategy of the cosmetic industry but a necessity because of human occupational activity and daily habits.     

Photosensitized Oxidation of Cyanide in Aqueous Solutions of Photoactive Modified Hydroxyethylcellulose

Novel water-soluble polymeric photosensitizers based on a natural polymer, naphthalene-modified hydroxyethylcellulose (HENC), were obtained and used for the photooxidation of cyanide. The reaction leads to the formation of cyanate. The process occurs via photoinduced electron transfer from CN⁻ to the naphthalene or naphthoquinone polymeric chromophores. The kinetics of the reaction depend on the degree of substitution of HENC, its concentration, and pH of the solution. The polymers can be easily removed after reaction as prolonged irradiation leads to their photodegradation.     

Integration studies on a two-stage fermentation process for the production of biohydrogen

Fermentation of biomass residues and second generation biomasses is potentially a way to enable a sustainable production of hydrogen. Simulation models which calculate mass and energy balances, developed with Aspen Plus^®, are used to integrate the process steps necessary to produce pure hydrogen from biomass in a 2-stage fermentation process. Process and heat integration are introduced to reduce the high water and heat demand of the process, connected to the low substrate concentrations in the involved process streams. The results show that the recirculation of process effluents, together with the use of properly designed heat exchangers, can reduce the water and heat demand up to 90% from a non-integrated process, but is also subject to restrictions due to an increase in osmolality in the system.     

Arsenic,cadmium, lead and thallium in coal ash from individual household furnaces

52 coal ash samples from individual households were analyzed to determine the pH and the concentrations of four toxic elements: arsenic, cadmium, lead and thallium. The method used was atomic absorption spectrometry with graphite-furnace atomization. The ash samples originated from various coal grades and statistical analysis showed existing correlations between the concentrations of studied elements, pH and the coal grades. The maximum concentrations of arsenic, cadmium, lead and thallium were 50,900, 43,500, 128,900, and 6660 µg/kg, respectively. The results were compared with the published data for the ash of industrial origin.

     

Assessment of the pollution and ecological risk of lead and cadmium in soils

The aim of the study was to assess the content, distribution, soil binding capacity, and ecological risk of cadmium and lead in the soils of Malopolska (South Poland). The investigation of 320 soil samples from differently used land (grassland, arable land, forest, wasteland) revealed a very high variation in the metal content in the soils. The pollution of soils with cadmium and lead is moderate. Generally, a point source of lead and cadmium pollution was noted in the study area. The highest content of cadmium and lead was found in the northwestern part of the area—the industrial zones (mining and metallurgical activity). These findings are confirmed by the arrangement of semivariogram surfaces and bivariate Moran’s correlation coefficients. Among the different types of land use, forest soils had by far the highest mean content of bioavailable forms of both metals. The results showed a higher soil binding capacity for lead than for cadmium. However, for both metals, extremely high (class 5) accumulation capacities were dominant. Based on the results, the investigated soils had a low (Pb) and moderate (Cd) ecological risk on living components. Soil properties, such as organic C, pH, sand, silt, and clay content, correlated with the content of total and bioavailable forms of metals in the soils. The correlations, despite being statistically significant, were characterized by very low values of correlation coefficient (r?=?0.12–0.20, at p?≤?0.05). Therefore, the obtained data do not allow to define any conclusions as to the relationships between these soil properties. However, it must be highlighted that there was a very strong positive correlation between the total content of cadmium and lead and their bioavailable forms in the soils.     

微生物浓度对SFBR工艺去除营养物的影响

采用序半连续式反应器(SequentialFed-batchReactor,简称SFBR,下同。)就不同微生物初始浓度对人工配置废水营养物去除效率的影响进行了研究。探讨了微生物初始浓度对COD、氮化合物(NH4-N和NO3-N)除去和微生物生长的影响。结果表明,当微生物初始浓度为140.4g/L时,COD有最高除去率(69.5%)。当微生物初始浓度≥46.8g/L,总氮除去率可达100%。菌体初始浓度对废水中营养物的去除有利。过高浓度的微生物生长,受营养物和供氧的限制。用一组涉及多个微生物反应的动力学模型,分析了微生物初始浓度对同时去除碳、氮化合物效率和微生物生长的影响。     

基质初始浓度对SFBR工艺去除营养物的影响

采用序半连续反应器就新鲜废水中COD/N比对COD、氮化合物去除效率和微生物生长的影响进行了研究。结果表明,新鲜废水中的COD/N比对COD和总氮去除率有明显的影响。当COD/N比由2.5增至12.5时,COD去除率由44.0%增至75.8%,总氮去除率从63.4%增至99.8%,然而,加料废水中COD/N比对微生物生长没有明显的影响。用一组涉及多个微生物反应的动力学模型,分析了COD/N比对同时去除碳、氮化合物效率和微生物生长的影响。