Search results for "Transports"
showing 10 items of 485 documents
Effect of Stacking Sequence and Sodium Bicarbonate Treatment on Quasi-Static and Dynamic Mechanical Properties of Flax/Jute Epoxy-Based Composites
2019
The present paper deals with the investigation of quasi-static and dynamic mechanical response of epoxy-based composites reinforced with flax and/or jute plain weave fabrics. In order to evaluate the influence of the stacking sequence, two monolithic laminates reinforced with flax or jute fibers and two hybrid flax/jute laminates were manufactured through the vacuum infusion technique. Furthermore, an eco-friendly and cost-effective surface treatment based on fiber soaking in a sodium bicarbonate solution was employed to improve the fiber-matrix adhesion. The mechanical characterization (by means of quasi-static flexural, dynamic mechanical thermal analysis and Charpy impact tests) allowed …
Comparative study between different methods for the efficiency of the production activity in the wood industry
2017
Generally speaking, the quality and cost of goods and in particular of the wood products is a decisive condition in their sales on the market, attracting buyers to satisfy their wishes and requirements. Starting from the general idea, by which it is considered that the manufacturing activity is effective if production is obtained at maximum quality with a low (minimum) cost, or when the revenue from the sale of products exceeds the market expenditure which is necessary to achieve it, this research article aims to study ways to make production more efficient by methods which could also be applied in the wood industry, by presenting a comparative study on production optimization methods in th…
Random vibration mitigation of beams via tuned mass dampers with spring inertia effects
2019
The dynamics of beams equipped with tuned mass dampers is of considerable interest in engineering applications. Here, the purpose is to introduce a comprehensive framework to address the stochastic response of the system under stationary and non-stationary loads, considering inertia effects along the spring of every tuned mass damper applied to the beam. For this, the key step is to show that a tuned mass damper with spring inertia effects can be reverted to an equivalent external support, whose reaction force on the beam depends only on the deflection of the attachment point. On this basis, a generalized function approach provides closed analytical expressions for frequency and impulse res…
Predicting stiffness and strength of birch pulp:Polylactic acid composites
2016
This paper studies failure of birch pulp–polylactic acid composites. Stiffness and strength are calculated using the theory of short fibre composites and the results are compared to experimental data. The results differed from the experimental values by 0–6%. With less aligned fibres the short fibre theory is not feasible. The performance of the 40 wt% birch pulp – polylactic acid composite is predicted with X-ray microtomography based finite element modelling, and the results are compared with experiments. Stiffness results differed from experiments by 1–17% . By adding into the models a third material phase representing the interface between the fibres and the matrix, the stress–strain c…
Modélisation de la mobilité : la génération de trafic à l'échelle régionale
2006
Public transport management is currently going through important changes, passing from one scale to another: decentralizing from the national level and extending at the local level. The range of transport management powers of the French administrative regions have widened, thus creating new management problems. Within the context of these new questions, our research proposes management solutions which take into account both the continual evolution of daily mobility and the new scales of transport management. More specifically, we considered a specific stage often neglected in geographical approaches to the suject. This stage called traffic generation consists in modelling the process of cho…
Autotransporta ietekme uz gaisa kvalitāti autoceļa A7 Ķekavas posmā
2022
Maģistra darbā “Autotransporta ietekme uz gaisa kvalitāti autoceļa A7 Ķekavas posmā” novērtēts autotransporta radītais atmosfēras piesārņojumu līmenis A7 Ķekavas posmā. Dati par satiksmes plūsmu tika iegūti izmantojot Latvijas Valsts ceļu stacionāra monitoringa datus, savukārt iedalījums pēc transportlīdzekļu klasēm veikts pamatojoties uz Valsts Centrālās statistikas pārvaldes apkopotajiem uzskaites datiem un CSDD apkopotās statistikas. Pētījuma praktiskajā daļā, lai veiktu scenāriju izstrādi un modelēšanu, izmantots AERMOD gausa dispersijas modelis. Modeļa datu ievadei izmantoti Latvijas Vides, ģeoloģijas un meteoroloģijas centra dati par meteoroloģisko apstākļu raksturojošiem parametriem …
Probabilistic Evaluation of the Adaptation Time for Structures under Seismic Loads
2016
Abstract In this paper, a probabilistic approach for the evaluation of the adaptation time for elastic perfectly plastic frames is proposed. The considered load history acting on the structure is defined as a suitable combination of quasi-statical loads and seismic actions. The proposed approach utilizes the Monte Carlo method in order to generate a suitable large number of seismic acceleration histories and for each one the related load combination is defined. Furthermore, for each load combination the related adaptation time is determined, if any, as the optimal one for which the structure is able to shakedown under the unamplified applied actions. A known generalized Ceradini's theorem i…
Rīgas apkaimju sasniedzamība ar sabiedrisko transportu
2015
Sabiedriskais transports ir viens no pilsētas attīstības veicinātājiem, savukārt, pilsētas sasniedzamība ir būtisks transporta un pilsētas struktūras kvalitātes indikators. Maģistra darbā „Rīgas apkaimju sasniedzamība ar sabiedrisko transportu” analizēta Rīgas iekšējā sasniedzamība, transporta plānošanas ietvars, pārvaldība, un izstrādāti adresēti priekšlikumi sasniedzamības optimizācijai. Maģistra darba mērķis ir izstrādāt plānošanas un pārvaldības risinājumu priekšlikumus Rīgas pilsētas sasniedzamības ar sabiedrisko transportu optimizācijai. Transporta plānošanai un pārvaldībai ir jābūt integrētai kopējā pilsētas plānošanas sistēmā, lai varētu tikt rasti kompleksi, starpdisciplināri risin…
Cost that is Directly Incurred as a Result of Operating the Train Service on the 1520 mm Rail with Primarily Freight Transportation
2016
AbstractUnder the Directive 2012/34/EU (21 November 2012) “the charges for … [rail] infrastructure … shall be set at the cost that is directly incurred as a result of operating the train service”. This charging rule is new for Baltic States’ railways, where due to the favorable geographic position a full cost application without detalization was possible. Although, a big number of relevant studies on the issue was made in EU, all of them covered only 1435mm railways with primarily passenger transportation. This study has been made in order to understand the impact of train operating on 1520mm rail infrastructure with primarily freight transportation.A gradual model of infrastructure chargin…
Fizikāli korekta attēla iegūšana
2015
Datorgrafika ir viena no populārākām datorzinātnes nozarēm, ar kuru ir saistīti ļoti daudz cilvēku, kas nodarbojās ar modelēšanu, animāciju, arhitektūru vai vienkārši kaut ko dara savam priekam vai pašizpausmei. Un visi šie cilvēki attēlu veidošanai izmanto objektīvu vai neobjektīvu renderēšanas algoritmu. Ja neobjektīvā algoritma rezultāts ir ļoti cieši saistīts ar autora domu un vīziju, tad objektīvā algoritma rezultāts būs ļoti tuvs fizikāli korektam un pietuvināsies fotogrāfijas kvalitātei. Darbā “Fizikāli korekta attēla iegūšana” ir aprakstīta un izpētīta renderēšanas algoritmu vēsture, algoritmu apraksti un atvērtā koda renderēšanas dzinēji, kas pielieto visus darbā minētos algoritmus.