The Ageing of Polyamide Fibres Under the Uv Radiation

the ageing of polyamide fibres under the uv radiation

BY

Vasile Blascu

An attempt has been undertaken to assess the effect of UV radiation on the molecular and supermolecular structure of polyamide fibres that are characterised by various macroscopic features, colours and additives. Based on the measurements performed, the general conclusion can be drawn that UV radiation under the exposure conditions used in our experiments causes changes in both molecular and supermolecular structuresof the investigated fibres. The extent of these changes is clearly dependent on the initial fibre structure, the modifiers added and the macroscopic features.

Pet and dyneema coated with polyaninline

BY

Liliana Rozemarie Manea, Anca Nechita and Vladan Koncar

In this paper, the conductive fibres have been obtained by chemical coating. The conductive polymer, PANI coated with poluethylenee terephtalate (PET) and Dyneema yarns. The electric conductivity of these fibres hase been investigated and results are discussed.

These fibres are intended for use in creating conducting yarns and realising connections in smart clothing or producing conductive fabrics which can be used as electromagnetic shields.

caractÉristique des forces de rÉsistance de l’air au filage À balon

BY

Florina-Liliana Buzescu

Dans ce travail on présente les principaux modèles mathématiques d’évaluation quantitative des distribution de forces de résistance de l’air exercées sur le fil qui forme le ballon, aux continus à filer aux anneaux.

Ces forces, dépendentes des vitesses des points du fil sur lesquels agissent, de ses paramètres géometrique et de sa structure, influencent le comportament dynamique du ballon du fil.

study of nonwovens used as substrates

BY

Iuliana Gabriela Lupu

This study underlines the influence of oven bonding process parameters on nonwovens charateristics. Analysing the values obtained by mathematical modeling is possible to establish the optimum values for the fabric density in order to ensure a good penetration of young plants through the nonwoven sheet.

the study of the weave influence on the yarn contraction within the fabric

BY

Daniel Chinciu and Marilena Ravas

In this paper the influence of the two processes, namely weaving and finshing, on the dimensional changes of the fabric and on the yarn is emphasised.

The intensity and the sense of these changes are due to the specificity of the technological process and the different behaviour of yarns depending on the nature of component fibres.

plane textile warp beaming driven with friction clutch and constant cycle of automatic control tension

BY

Dumitru Liute and Daniela Liute

The paper has presented the calculus equations for the cyclic variation of winding tension of plane textile and kinematic cycle of self-regulation of beam revolution. The calculus equations of kinematic cycle of automatic control allow the conception of some kinematic schemes of actioning of the rolls which does not need the use of the floating tension rolls or of the detector pulleys of the winding diameter for the self-regulation commands.

the study of the weave influence on the compactness degree

BY

Dorina Oana and Daniel Chinciu

This work presents the results obtained from the study concerning the sense and intensity of the weave influence on the compactness degree level. On these bases, the possibilities have been established to improve the homogeneity of the internal structure of stripped cloth obtained by combining weaves with significantlty different mean float.

the study of the weave influence on the fabric mass

BY

Marilena Ravas and Daniel Chinciu

In this paper the weave influence on the fabric mass is emphasised, the weave being on the thrid place after the compactness and count of the yarn systems.

Original calculus relations for the fabric mass depending on the weave through the average floating have been proposed.

Zugdehnungsverhalten der biaxial-gestricken

VON

Constanta Comandar

Die Zugkraftenberchnung für eine Biaxial-Gestrick ist ein statisch unbestimmtes Problem. Um die Zugkraft zu berechnen kann man eine einzige Gleischung schreiben mit zwei Unbekantnen: Fz und Fm. Die Lösung für ein solches Problem ist eine zusätzliche Gleichung aus der Analyse der Dehnungen zu schreiben, wie z. B. die Probedehnung unter die F – Kraft ist mit dem Wert & gleich. Um bei Biaxial-Gestricken das Dehnungsverhalten besser interpretiert und Schlussfolgerungen ziehen zu können, ist es notwenig, das Verhalten der Einzelkomponenten mit Reibung zu kennen. Deswegen soll das Verhalten der Einzelkomponenten mittels Zugversuch ermittelt werden. Dazu werden aus einem biaxial verstärken Gestrickstück drei gleiche Proben zugversucht: Probe A – ohne Maschenfäden, Probe B – ohne zusätzlichen Systemen, Probe C – Biaxial-Gestrick. Das Diagramm der probe C weißt zwei Bruchwerte des Biaxial-Gestricks auf. Der erste Peak entsteht durch den Bruch der Verstärkungsfäden und entspricht etwas dem Diagramm der Probe A und der zweite Peak ist den Bruch der Maschenfäden und entspricht dem Peak aus Diagramm der Probe B.

some aspects about the geometrical properties of warp knitted fabrics

BY

Mirela Blaga and Mihai Penciuc

The knowledge of geometrical prperties of knitted fabrics is of great importance from the point of view of producing engineering products for both consumer and industrial use.

This research points out the parameters with a big influence on the warp knitted fabrics properties: the yarn run-in, the take-up and the lapping (underlap amplitude). The fabrics to be analysed were produced on Copcentra E28 warp knitting machine, during a training stage at Liba Co, Germany. The chosen structures were made with two fully threaded guide bars, with usual lapping (locknit, reverse locknit, satin, etc) with the end-use underwaer or technical articles. For each structure, technological parameters were adjusted with different values (yarn run-in and fabric take-up).The determined geometrical properties in this research were: the fabric stitch density, thickness, width and weight.

The paper presents results and discussions about the influence of the structural parameters (underlap amplitude) and of the technological parameters (yarn run-in and fabric take-up) on the fabric properties.

la diversification constructive et technologique des poche exterieures des produits de maroquinerie

PAR

Floretina Harnagea

Les poches, des components importantes des produits de l’industrie de maroquinerie, jouent un role très important dans le dévelopment constructive et technologique de celle-ci. On y presente des varies modèle de poche qui se différentient par: la consommation spécifique, la norme de temps, la facilité d’utiliser le produit et la sécurité des objets. A l’aide des critères, on a établi la variante optime de modèle de poche.

mathematical models involved in acrylic polymer coating

BY

Silvia Mihuta, Aurelia Grigoriu and Michaela Dina Stanescu

A number of parameters (xk) representing the properties of acrylic polymer films have been studied in order to obtain the best composition for coating textile materials. There are two x variables, namely x1 the concentration of coating polymer and x2 the concentration of agglutinant. The analysed property is the stiffness of the coated material. The mathematical modelling has been done using an experimental programme. The optimum variation ranges have been proposed.

Assembly line balancing – heuristic approach

BY

Octav Brudaru and Cintia M. Copaceanu

Assembly line balancing is one of the important problems of production/operations management area. Due to the NP-hard nature of this problem, heuristics are generally used to solve real life problems. In this paper we are going to review and to analyse the heuristic methods able to solve this problem and its variants. Meta-heuristic algorithms like genetic algorithms and simulated annealing are considered in this review due to their ability to find very good solutions to real life problem instances.

the relation between the management of the company and its functions

BY

M. Irimia and Anca Brudaru

In the conditions of market economy, the subjects of lucrative and creative activities are acknowledged and analysed as economic units. As a rule, the efficient activities are the result of some fluent relations in the process of exerting the attributes of management together with the venture’s functions. In order to achieve an advantageous synchronisation of the relations of management and the management process, is necessary an overlapping of the intrinsic and explicit functions of the company. In our opinion, the result of these complex interrelations will generate not only the sustainable development of the national economy but also the superior fulfillment of present and future needs. This work also enlarges upon the necessary conditions that a firm must carry out in order to avoid an unwanted obstruction of the mentioned process.

management de la maintanance conditionelle. etude de cas: analyse et diagnostic d’un ventilateur de tirage par analyse vibratoire

PAR

Ali Benretem, Ali Haddouche, Rachis Chaib et Ion Verzea

The vibrations generated by the revolving machines such as the ventilators, the compressors translate the dynamic stresses generated by its moving parts. The analysis of the vibratory signatures makes it possible to draw up a diagnosis of the operating conditions of the machine and to detect the defects at an early stage.

The maintanance of the machines by analysis of the vibrations is described as predictive because it thus make it possible to better manage the failures while intervening before breakage, at the time of programmed stops, by reducing the risk of consecutive innoportune stops of production to a sudden break down. The vibratory analysis allows the diagnosis: of a misalignment or an imbalance on a driveshaft, defects of tightening, electromagnetic disturbances on an engine, the state of the blades of a ventilator, paddles of a pump.

This work contains a study of a diagnosis for a ventilator intended to evacuate gases resulting from the combustion of a boiler towards the chimney. The ventilator is of axial type on two floors, which turns at a speed of 600 rpm.

le retour d’experience pour le management de la maintanance des systÈmes techniques, analyse et synthese de donÉes

PAR

Mohamed Benidir, Rachid Chaib et Ion Verzea

Une machine industrielle est un équipment complexe, sujet à des multiples modes de défaillances où les causes de pannes et/ou d’incidents sont multiple. La maitrise de ces pannes devient de plus en plus un capital important dans une entreprise. Actuellment, elle est considerée comme une facteur de stratégie et de productivité surtout vis à vis la concurence actuelle. Il s’agit essentiellment de capitaliser la connaissance, de la faire partager et de la fructifier, voire enrichir le projet de conaissance du terraiin et des pathologies (pertes de fonction) susceptible de se produire. Cette approche permet, en utilisant les outils d’aide à la décision de détecter les composants les plus critique, de déterminer l’ordre de priorité des actions de maintanance à mener et de diriger la procédure d’exploitation vers les maillons les plus pénalisant dans une entreprise, voire définir les modifications nécessaires par une nouvelle conception. Ainsi, apprécier le comportment pathologique du matériel et augmenter sa disponibilité.