The main purpose of this article is to present an author’s methodology of production levelling
and to show the impact of levelling on the time during which the product passes
through the process and on staff performance. The article presents the analysis of literature
concerning the method of improving the production process, especially taking production
levelling into consideration. The authors focussed on the definition and methodologies of
production levelling. A diagram of interrelations showing determinants and efficiency measures
of production levelling as well as an author’s production levelling methodology have
been presented. An example of the implementation of production levelling in one of the departments
of a company manufacturing surgical instruments has also been shown. Analysis
of the current state, stages of implementation and end effects have been presented. Attention
was focussed on the time during which the product passes through the process and on staff
performance.
The Decision Makers in the production organizations, which produce multiple different products
at the same time, set the priorities for what the organization desires to produce. This
priority is sorting the products in order to schedule the production based on these priorities.
The production organizations receive a huge number of orders from different customers, each
order contains many products with close delivery dates. The organization aims to produce
multiple different products at the same time, in order to satisfy all customers by delivering
all orders at the right time. This study will propose a method to prioritize the production
to produce a multiple different products at the same time, the production lines will produce
multiple different products. This method will prioritize the products using Multi Criteria
Decision Making technique, and prioritize the production operations using a new algorithm
called Algorithm for Prioritization of Production Operations. In addition, the study will provide
an algorithm for production scheduling using the production priority calculated based
on the proposed method. The study will also compare the scheduling based on the priority
rules and based on the proposed method through total production time and the variety of
products produced.
Agriculture is a signifi cant source of gaseous pollutants such as ammonia, methane, nitrous oxide and volatile organic compounds. Ammonia is particularly important due to the high emission and local, as well as global impact on the environment. The release of NH3 is one of the main ways of nitrogen emission to the atmosphere and it contributes to its subsequent deposition. The aim of the study was to analyze ammonia emissions from animal production in Poland in 2005–2017, its regional diversity and possibilities of its reduction in agriculture. The ammonia emission was calculated for the animal production groups according to the NFR classifi cation. The values of ammonia emission were calculated based on ammonia emission factors used by KOBIZE, in accordance with the EMEP/EEA methods. In 2017, the NH3 emission from Polish agriculture amounted 288 Gg and it accounted for 96% of the emission in 2005. Ammonia emission from livestock production, in 2005–2017, on average accounted for 79.8% of agricultural emissions. The largest share had the cattle (51%) and swine (30%) production. The NH3 emissions differed strongly between provinces. The emission density (kg NH3·km-2·year-1) in provinces with intensive livestock production was about 5.5 times higher than in regions, where livestock production was the lowest. The mitigation strategies should be implemented primarily in provinces where reduction potential is the largest. The assessment of the reduction potential should take into account the NH3 emission per 1 km2 and the low
NH3 emission technologies, which are already applied in the regions.
In this paper a 600 MW oxy-type coal unit with a pulverized bed boiler and a membrane-cryogenic oxygen separator and carbon capture installation was analyzed. A membrane-cryogenic oxygen separation installation consists of a membrane module and two cryogenic distillation columns. In this system oxygen is produced with the purity equal to 95%. Installation of carbon capture was based on the physical separation method and allows to reduce the CO2emission by 90%. In this work the influence of the main parameter of the membrane process – the selectivity coefficient, on the efficiency of the coal unit was presented. The economic analysis with the use of the break-even point method was carried out. The economic calculations were realized in view of the break-even price of electricity depending on a coal unit availability.
Finite fossil fuel resources, as well as the instability of renewable energy production, make the sustainable management of energy production and consumption some of the key challenges of the 21st century. It also involves threats to the state of the natural environment, among others due to the negative impact of energy on the climate. In such a situation, one of the methods of improving the efficiency of energy management – both on the micro (dispersed energy) and macro (power system) scale, may be innovative technological solutions that enable energy storage. Their effective implementation will allow it to be collected during periods of overproduction and to be used in situations of scarcity. These challenges cannot be overestimated - modern science has a challenge to solve various types of problems related to storage, including the technology used or the control/ /management of energy storage. Heat storage technologies, on which research works are carried out regarding both storage based on a medium such as water, as well as storage using thermochemical transformations or phase-change materials. They give a wide range of applications and improve the efficiency of energy systems on both the macro and micro scale. Of course, the technological properties and economic parameters have an impact on the application of the chosen technology. The article presents a comparison of storage parameters or heat storage methods based on different materials with specification of their work parameters or operating costs.
The last two decades have brought a significant modernization in methods of cultivation in greenhouses. Soilless cultures, isolated from soils, have become a common practice, similarly as fertigation (fertilization + irrigation) installations, although most of them are applied in the open system (with no recirculation), where excess nutrient solution is removed straight to soil. This situation was the reason why it was decided to conduct studies, extended over a period of many years, on the estimation of environmental pollution caused by discharged drainage waters containing mineral fertilizers in economically important cultures in Poland (anthurium, tomato, cucumber). On the basis of the chemical composition of drainage waters and amounts of nutrient solution spillway from culture beds data were estimated concerning pollution of the soil medium by the nutrient solution. The level of pollution was dependent on nutrient requirements of crops and the length of the vegetation period. The highest environmental pollution is caused by intensive tomato growing (in kg·month·ha-1): N-NO3 (up to 245), K (up to 402), Ca (up to 145) and S-SO4 (up to 102). A lesser threat is posed by metal microelements: Fe (up to 2.69), Mn (up to 0.19), Zn (up to 0.52) and Cu (up to 0.09). Lower contamination of the natural environment is generated in cultures with lower nutrient requirements (anthurium) and in the case of culture on organic substrates. With an increase in ecological awareness of producers recirculation systems should be implemented in the production practice, in which drainage waters do not migrate directly to soil, but are repeatedly used to feed crops.
In this study, batch fermentation of glucose to ethanol by Saccharomyces cerevisiae (ATCC 7754) was carried out using 2.5 dm3 BioFlo®115 bioreactor. The main objective of this study was to investigate the kinetics of ethanol fermentation by means of the non-structured model. The fermentation process was carried out for 72 h. Samples were collected every 4 h and then yeast growth concentration of ethanol and glucose were measured. The mathematical model was composed of three equations, which represented the changes of biomass, substrate and ethanol concentrations. The mathematical model of bioprocess was solved by means of Matlab/SimulinkTM environment. The obtained results from the proposed model showed good agreement with the experimental data, thus it was concluded that this model can be used for the mathematical modeling of ethanol production.
The purpose of the paper is to present the author’s reflections on the origin and popularity
of various approaches to maintenance and improvement of production processes, their
terminological consistency, understanding, and practical application of their principles. The
author’s reflections are based on his observations made over his many years of activity as
a lecturer and consultant in the area of production engineering and management. It was
shown that there is a need to make scientists and practitioners aware of the relatively large
degree of freedom in defining the scope and way of application of strategies of continuous
improvement. The author’s proposal is to refer to all approaches to maintenance and improvement
of production processes with the title “Strategies of Efficient Action” and all
supporting methods as “Practices of Efficient Action”.
Considerations presented in the paper can be useful in more and more efficiently applying
the power of TQM, Six Sigma, Lean Manufacturing and other strategies of processes
maintenance and improvement in the daily activities of companies.
The growth of the global population, urbanization as well as economic and industrial development, affect the continuously increasing demand for mineral aggregates. The current assessed global production of mineral aggregates amounts to 50 billion Mg/year, which statistically approximates 6.5 Mg per an inhabitant of the globe. In terms of consumption volume, water is the only raw material ahead of aggregates. Despite such a great scale, in many countries and regions the extraction and production of aggregates belong to the least regulated sector of human activity. This refers particularly to the countries of A sia, A frica, and North A merica, where both the resources and the extraction of aggregates, particularly of sand and gravels, are either not monitored and registered. It significantly increases the negative impact on the natural environment, due to the destruction of riverbeds and oxbows, coastal erosion, drying up cultivation areas, etc. In the reports, local terminology of aggregates often functions, which makes it difficult to compare them and prepare appropriate balances. In order to regulate the unfavorable situation, one of the main conclusions of the Report (UNEP 2019) is the need of implementing a common requirement to plan and monitor the process of extraction of natural resources. The paper presents the possibility of forecasting the extraction and producing aggregates based on the consumption of cement, i.e. the basic building material. A lthough the analyzed coefficient of mineral aggregate production per unit of cement consumption (production) varies, its advantage is the fact that the production of cement is identified and taken into account in balances of industrial production of the majority of countries, whereas such identification for mineral aggregate production are still lacking.
The article presents the possibility of using the Cobb-Douglas production function for planning in a turbulent environment. A case study was carried out – the Cobb-Douglas function was used to examine the condition of the Polish hard coal mining industry and the progress which has been made after undertaking certain activities aimed at increasing the competitiveness of coal companies over recent years. Only the correct and confirmed identification of the causes of irregularities in the production process can allow for the introduction of effective remedies. The effectiveness of the solutions proposed by the author has been confirmed thanks to the simulation during which the impact of the proposed production strategy on the parameters of the CD function was examined. Three variants of production functions models were created and production productivity rates and marginal substitution rates were determined. The results enabled the verification of the progress of restructuring as well as identification of the origin of the observed problems and comparison of the current state with the results of analyses carried out in previous years. Scenarios of possible trend developments for the factors introduced into the function model in order to present remedial measures that could improve the process of hard coal extraction were created. The scenarios were created using the ARIMA class models. Which scenario is the most favourable was determined. A computer program, created by the author, for optimising the level and use of labor resources at the level of the entire coal company has been presented.