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Determination of Chemical Composition of Plums During Pre-Treatment and Drying
Dorota Walkowiak-Tomczak
Ecological Chemistry and Engineering S , 2012, DOI: 10.2478/v10216-011-0009-8
Abstract: Thanks to drying, fruits are available on the market throughout the year. Parameters of drying conditions affect eg the content of bioactive compounds in the product. The aim of the study was to investigate the effect of pretreatment conditions and the applied drying method on changes in the chemical composition of plums. Analyses were conducted on plums cv. 'Valor', which were subjected to pre-treatment including blanching, drilling and osmotic dehydration. Next they were dried by the convection method at air temperature of 60°C and flow rate of 1.5 m/s. Dehydration was run in a 61.5% sucrose solution at a temperature of 50°C for 1 or 2 h. Convection-dried plums, with no osmotic dehydration applied, constituted the reference sample. In fresh, dehydrated and dried fruits determinations included dry matter, polyphenols by colorimetry with the Folin reagent and contents of sugars by colorimetry using 3,5-DNS acid. As a result of blanching and dehydration the content of dry matter increased. Water loss after dehydration amounted to as much as 1.45 g H2O/g d.m.0 after 2 h in comparison with blanched plums. As a result of dehydration total contents of sugars and polyphenols in plums decreased (mg/100 g d.m.). In convection-dried prunes the content of polyphenols was by 30÷50% higher than in the raw material, but lower than in the reference sample.
Changes in antioxidant activity of black chokeberry juice concentrate solutions during storage
Dorota Walkowiak-Tomczak
Acta Scientiarum Polonorum : Technologia Alimentaria , 2007,
Abstract: The aim of the study was to determine the effect of pasteurization and storage conditions of black chokeberry juice concentrate solutions on their antioxidant activity. The study investigated the effect of solution pH (3-5), temperature (10-30°C) and storage time (0-20 days), as well as oxygen availability. Solutions were obtained by diluting concentrate with buffers according to McIlvaine to anthocyanin contents of 20 mg%. They were next pasteurized and stored in the dark under conditions specified in the experimental design. Antioxidant activity was determined colorimetrically using the cation-radical of 2’2-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS). Antioxidant activity decreased in all samples, both after pasteurization and after storage. The biggest effect on the lowering of antioxidant activity was found for oxygen availability rate during pasteurization and storage, and for storage temperature.
Physico-chemical properties and antioxidant activity of selected plum cultivars fruit
Dorota Walkowiak-Tomczak,Julita Regu？a,Grzegorz ？ysiak
Acta Scientiarum Polonorum : Technologia Alimentaria , 2008,
Abstract: The aim of the study was to present and compare characteristics of pomological parameters, colour, dry matter and solids contents, as well as antioxidant activity of fruit of selected plum cultivars. Analyses were conducted on plums (Prunus domestica) of three cultivars: ‘W gierka Zwyk a’, ‘Bluefre’ and ‘Elena’. Presented morphological parameters of fruit and stones included their length, width and weight, as well as mean fruit size and firmness. Fruit colour was measured by spectrophotometry in the L*a*b* system. Contents of dry matter and solids were determined in fruits. Moreover, Trolox-equivalent antioxidant capacity (TEAC) of plums was assayed by colorimetry using a cation radical ABTS. The biggest fruits were found for cv. ‘Bluefre’, while the highest value of dry matter and solids contents – in cv. ‘W gierka Zwyk a’. Higher antioxidant activity (μM Trolox/g d.m.) was assayed in plums of relatively new cultivars, ‘Bluefre’ and ‘Elena’, in comparison to the traditional cultivar ‘W gierka Zwyk a’.
Model biomasy igliwia sosny zwyczajnej (Pinus sylvestris L.) wyros ej w warunkach gruntów porolnych i le nych
Tomasz Jelonek, Witold Pazdrowski, Ryszard Walkowiak, Arkadiusz Tomczak
Forest Research Papers , 2012, DOI: 10.2478/v10111-012-0009-1
Abstract: The relationship between the biometric traits of Scots pine (Pinus sylvestris L.) trees and their total needle biomass was analysed and the foliage of these trees growing in 38 stands in northern and western Poland was modelled. Productive pine stands were chosen on former farmland and forest soil providing locally optimal conditions for growth. A total of 114 trees aged between 32 and 114 years old were felled and their total biomass of fresh needles was calculated. Out of all the traits measured, diameter at breast height (DBH) was the best predictor of foliage biomass. Since the two models produced to describe this relationship on forest soils (Mi = 0.093614 D1.31.679398), and farmland (Mi = 0.060302 D1.31.819009) were very similar, they may be used interchangeably. However, as they aged, needles of pines growing on former farmland deteriorated faster than those on forest soil with respect to their assimilation capacity. This suggests that the assumptions of Pipe Model Theory need to be verified.
Maximizing residual capacity in connection-oriented networks
Krzysztof Walkowiak
Advances in Decision Sciences , 2006, DOI: 10.1155/jamds/2006/72547
Abstract: The following problem arises in the study of survivable connection-oriented networks. Given a demand matrix to be routed between nodes, we want to route all demands, so that the residual capacity given by the difference between link capacity and link flow is maximized. Each demand can use only one path. Therefore, the flow is modeled as nonbifurcated multicommodity flow. We call the considered problem nonbifurcated congestion (NBC) problem. Solving NBC problem enables robust restoration of failed connections in a case of network failure. We propose a new heuristic algorithm for NBC problem and compare its performance with existing algorithms.
A Lagrangean Relaxation Algorithm for Flow Optimization in Survivable MPLS Networks
Krzysztof Walkowiak
Theoretical and Applied Informatics , 2010, DOI: 10.2478/v10179-010-0017-x
Abstract: The problem that this paper investigates, namely, the working route assignment (WRA) problem, is one that arises naturally from problems of survivable network design that have recently received significant attention in data networking community. We consider an existing MPLS backbone transport network, which is in an operational phase and augmenting its resources is not possible. To address the issue of network survivability we apply restoration, i.e. after a network failure broken connections are dynamically restored. The main goal of our work is twofold. First, we want to develop an effective objective function for optimization of working routes in order to scale network flows and prepare the network for future failures and restoration. Second, we plan to find an efficient method to solve the WRA problem with this new objective function. Therefore, a function called RCL (Residual Capacity and Lost Flow in Link) facilitating the function LFL (Lost Flow in Link) developed previously by the author is formulated. Next, we present an approximation approach, called Lagrangean relaxation with heuristics (LRH) aimed to solve WRA with RCL as objective function. We further draw comparisons between LRH and an existing heuristic based on Flow Deviation algorithm. We also examine the performance of RCL against other functions in the context of network survivability. The results of simulation tests demonstrate that the new algorithm provides sub-optimal results, which are significantly better than other heuristic and the new function RCL can be effectively applied for assignment of working routes in survivable MPLS networks.
MINORITY LANGUAGE POLICY REGARDING PERSONAL NAMES – AN OVERVIEW
Justyna Walkowiak
Eesti ja soome-ugri keeleteaduse ajakiri , 2011,
Abstract: Language Policy (LP) with language planning as its implementation is now a well-established field; yet, as evidenced by the scarcity of scholarly literature, seldom concerned with personal names. The paper looks at personal names (given names and surnames) and discusses the ways in which they can be perceived as objects of minority LP. Policies regarding personal names are analysed within the framework of the traditional division of language planning into status, corpus and acquisition planning. These policies are then further examined according to other dimensions: what the object of a LP is, who its agent is, what motivates a LP, what effects it exerts, and how a LP is carried out. Finally, the paper looks at EU minority legislation with reference to personal names,especially at the country-specific opinions which reflect the FCNM monitoring process, highlighting areas of controversy. In conclusion, it is shown how vital personal names are to personal and group identity and, consequently, how control over them helps the nation-state control a minority, although – it is argued – not every regulation constitutes a minority LP.
Vertex Detection for a Charm Tag in e+e- -> W+W- at a High Energy Electron-Positron Linear Collider
Wolfgang Walkowiak
Physics , 2001,
Abstract: The study of the process $e^+e^- \to W^+W^-$ at Linear Collider energies presents a good opportunity to investigate anomalous triple gauge boson couplings and $W^+_LW^-_L$ rescattering. The helicity analysis of the $e^+e^- \to W^+_LW^-_L$ decays will benefit if the charm quark containing jet can be identified for events which contain one hadronic $W$ boson decay to a charm and another quark. A JAVA implementation of the SLD collaboration's topological vertex finding algorithm (ZVTOP) in the linear collider analysis framework has been used to extract charm tag efficiencies and purities based on vertex multiplicities.
Random Approach to Optimization of Overlay Public-Resource Computing Systems
Grzegorz Chmaj , Krzysztof Walkowiak
International Journal of Electronics and Telecommunications , 2010, DOI: 10.2478/v10177-010-0007-2
Abstract: The growing need for computationally demanding systems triggers the development of various network-oriented computing systems organized in a distributed manner. In this work we concentrate on one kind of such systems, i.e. public-resource computing systems. The considered system works on the top of an overlay network and uses personal computers and other relatively simple electronic equipment instead of supercomputers. We assume that two kinds of network flows are used to distribute the data in the public-resource computing systems: unicast and peer-to-peer. We formulate an optimization model of the system. After that we propose random algorithms that optimize jointly the allocation of computational tasks and the distribution of the output data. To evaluate the algorithms we run numerical experiments and present results showing the comparison of the random approach against optimal solutions provided by the CPLEX solver.
Pre-Paid Charging System for Sip-P2P Commercial Applications
Damian Nowak,Krzysztof Walkowiak
International Journal of Computer Networks & Communications , 2011,
Abstract: The new SIP-P2P approach brings many advantages like the improved reliability and the ease of setup.However, Communications Service Providers (CSPs) offering VoIP services seem to be afraid to losetheir profits due to the introduction of SIP-P2P. Claimed is the lack of session establishment controlleading to revenue leakages. In this work we introduce a charging system for SIP-P2P that assures CSPs’revenue from using SIP-based peer-to-peer communications commercially. The proposed solutionconsists of a new “carrier-grade P2P network” concept, software modification of existing equipment andgives some charging application design guidelines. An application prototype was implemented toexamine the concept. Additionally, experiments were done to provide the methodology for systemdimensioning.
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