Wyniki wyszukiwania - BazTech

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Production flow synchronisation versus buffer capacities in assembly systems

Dobrzańska-Danikiewicz A., Krenczyk D.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 29, nr 1

91-98

EN

Purpose: The goal of the considerations carried-out in that paper is the determination of the system synchronisation conditions. Those conditions concern capacities of system buffers. The fulfilment of the developed conditions should guarantee the production flow synchronisation into the expected steady state determined by the system bottleneck. In analysed assembly system rhythmic concurrent production with wide assortment is realised. Design/methodology/approach: The considerations presented in that paper are rooted in the authority method called Requirements and Possibilities Balance Method (RPBM). The experiments in the computer simulations programmes have been carried-out within the confines of the researches. The computer simulation models of the assembly systems using Taylor II for Windows and Enterprise Dynamics have been built. Findings: There are two kinds of system buffers: the entrance buffers and the inter-resources buffers in the assembly systems. The interdependences informing about the required number of elements allocated into the system buffers in order to the production realisation during the first cycle of the system steady state has been formulated. Moreover, the minimal buffer capacities have been determined. Research limitations/implications: The developed interdependences constitute the first step towards formulation of the automatic method designed for the automatic construction of rules controlling the system work during system transition state. That method should enable the automation of the system buffers filling-up. Practical implications: The presented system synchronisation conditions can become an integrated part of existing authority computer system. It aids the decision-making process connected with production planning and control. Originality/value: To develop the interdependences is the main achievement of the given paper. The presented approach permits to solve the problem concerning the production flow synchronisation into the expected steady state determined by the system bottleneck.

2

Required buffer capacities in assembly systems

Krenczyk D., Dobrzańska-Danikiewicz A.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 23, nr 1

95-98

EN

Purpose: The aim of the realised analysis is the determination of the set of conditions. The fulfilment of those conditions enables the synchronisation of the assembly system work into the steady state. It is necessary to specify the rules controlling the assembly system work. Rhythmic concurrent production with wide assortment in the considered assembly system is realised. Design/methodology/approach: The theoretical roots of the considerations presented in that paper include theory of constraints. The presented approach is consistent with the authority method called Requirements and Possibilities Balance Method (RPBM). Findings: Two kinds of system buffers: the entrance buffers and the inter-resources buffers are considered in that paper. The number of buffers elements needed for production during first steady state of the given system has been determined. Mathematical formulas specifying the minimal capacity of the buffers allocated in the assembly system have been outworked. Research limitations/implications: The formulas specifying the minimal buffer capacity constitute the first step towards formulation of the automatic method. That method is designed for the automatic construction of rules controlling the system work during transient phases between two different steady states. The process enables automation of the introduction filling of the system buffers. Practical implications: The presented formulas can become an integrated part of existing authority software. The developed computer system aids the decision-making process connected with production planning and ensures effective utilisation of production resources. Moreover, the formulas correctness during computer simulations has been verified. Originality/value: To develop the formulas specifying the minimal capacity of the system buffers is the main achievement of the given paper. The presented approach permits to solve the problem concerning the synchronisation of the assembly system work into the steady state.

3

Assessment of copper and zinc stabilization process in soils after the application of brown coal, sugar beet leaves and cement

Diatta J.B., Grzebisz W., Wiatrowska K.

Chemia i Inżynieria Ekologiczna

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2007

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Vol. 14, nr 2

181-189

EN

Reports results of investigations dealing with copper and zinc stabilization in metal-spiked soils by applying brown coal (BC), sugar beet leaves (SBL) and cement (CEM) designated as stabilizers were reported. The incubation experiment consisted of two soils ie, loamy sand (No. 1) and light loamy sand (No. 2) spiked with Cu and Zn as Cu(SO4)2 o 5H2O and Zn(SO4)2 o 7H2O, respectively at the rates: 0, 100, 500, 1000, 3000 and 7000 mg o kg-1. Stabilizers were added at the rate 0, 1 and 3 % (on dry weight basis) after a 4-week pre-incubation of metal-spiked soils and treatments were further incubated for 16 weeks. Results show that pH decreased gradually along with Cu and Zn rates. Bioavailable (extracted by 0.1 M NaNO3) amounts of Cu and Zn indicate that the retention capacity of both soils was strongly impaired at metal spiking just above 100 and 3000 mg o kg -1, typically for soils No. 1 and No. 2, respectively. This was supported by the values of the maximal buffering capacity (MBC) and the changes of Gibbs free energy (DeltaG0) The stabilization efficiency at the rate 3000 mg Cu and Zn kg-1 may be ranked as follows: pH: CEM > SBL > BC and based on MBC (Cu mostly): CEM > SBL > BC.

PL

Przedstawiono wyniki badań nad stabilizacją miedzi i cynku w glebach sztucznie nimi zanieczyszczonych przy utyciu węgla brunatnego (BC), liści buraka cukrowego (SBL) i cementu (CEM) określanych jako stabilizatorów. Doświadczenie przeprowadzono w warunkach inkubacyjnych i składało się z dwóch gleb: piasku gliniastego mocnego (Nr 1) i piasku gliniastego lekkiego pylastego (Nr 2), do których dodano wzrastające dawki Cu i Zn: 0, 100, 500, 1000, 3000, 7000 mg Zn i Cu kg-' gleby odpowiednio w postaci [Cu(SO4)2 o 5H2O] i[Zn(SO4)2 o 7H2O]. Stabilizatory dodano w dawkach 1 i 3%, po 4 tygodniach inkubacji gleb z Cu i Zn i dalej inkubowano przez 16 tygodni. Otrzymane wyniki wykazały, że pH malało stopniowo wraz ze wzrostem dawek Cu i Zn. Biodostępne (ekstrakcja przy utyciu 0,1 M NaNO3) ilości Cu i Zn wskazały na silne osłabienie właściwości sorpcyjnych gleb już odpowiednio od dawek 100 i 3000 mg kg-' dla gleby Nr 1 i Nr 2. Znalazło to potwierdzenie w wartościach maksymalnej pojemności buforowej (MBC) oraz entalpii swobodnej (?G0). Skuteczność stabilizacji przy dawce 3000 mg Cu i Zn kg-' można uszeregować następująco: pH: CEM > SBL > BC oraz MBC (bardziej dla Cu): CEM > SBL > BC.

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Wpływ zmian zachodzących podczas składowania trocin sosnowych na właściwości płyt wytwarzanych z ich zastosowaniem

Frąckowiak I.

Drewno : prace naukowe, doniesienia, komunikaty

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2005

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vol. 48, nr 173

81-94

PL

W artykule przedstawiono skład frakcyjny i pojemność buforową sosnowych trocin tartacznych świeżych (przed składowaniem) oraz składowanych przez pół roku w warunkach przemysłowych. Omówiono wpływ czasu i położenia trocin w hałdach na te właściwości. Wytwarzano trzywarstwowe płyty z trocin składowanych w różnym czasie. Parametry i warunki wytwarzania płyt oraz surowce chemiczne, zgodne z aktualnie stosowanymi w produkcji płyt wiórowych, były czynnikami stałymi. Zbadano wytrzymałość płyt na zginanie statyczne i rozciąganie prostopadłe do płaszczyzn, spęcznienie płyt po moczeniu w wodzie oraz zawartość formaldehydu. Wyniki badań wykazały, że powyższe właściwości płyt są zdeterminowane kwasową pojemnością buforową trocin, której wartość jest ściśle związana z warunkami ich składowania. Od warunków tego procesu zależy, w dużej mierze poziom i stabilność właściwości płyt oraz pośrednio efektywność produkcji.

EN

The process of storing sawdust in the industrial scale was examined in experimental heaps of the following size: height 15 m, width 25 m, and length 45 m. The method of forming the heaps and placing in them study samples stored for different periods of time were described. Throughout the whole storage period,, temperature in the heaps was controlled by means of probes inserted in the heaps when they were formed. Fraction composition and buffer capacity of fresh sawdust (prior to the storage period and when stored already for 4 and 6 month) were examined throughout the whole width of the heaps at different distances from the ground. Fraction composition and buffer capacity of sawdust were determined.