The paper presented the model of a problem of choosing the location of a car crane for the installation of prefabricated elements in a given assembly situation with the solution proposal. The issue relates to the situation, in which the dimensions of the shielding structure (assembled) are specified, sizes and weights of the prefabricated elements with their location on the structure. The solution seeks the best location of a crane from the point of view of the parameters of the crane, scope and height of the lift.
The introduction of the sustainable development elements in the construction industry leads to finding new ways of using waste minerals that are difficult in storage and recycling. Coal combustion products have been already introduced into building materials as a part of cement or concrete but they have been thought insufficiently compatible with the polymer-cement binders [7]. The paper presents results of the mechanical properties of polymer-cement composites containing two types of mineral additives: waste perlite powder that is generated during the perlite expanding process, and calcium fly ash which is the byproduct of burning coal in conventional furnaces. Mechanical tests of polymer-cement composites modified with wastes were carried out after 28 and 90 days of curing. As a part of preliminary study specific surface area and particle size distribution of mineral wastes were determined.
VTT Technical Research Centre of Finland Ltd. has developed and utilized Low Temperature Co-fired Ceramic (LTCC) technology for about 25 years. This paper presents our activities related to photonics and millimetre-waves, including also a relevant literature survey. First a short summary of the technology is given. Especially, the unique features of LTCC technology are described in more details. In addition, several examples have been given to show the validity of LTCC technology in these high-performance fields.
Crane selection is an important issue in assembly works planning. Tower and telescopic, stationary and mobile cranes used in construction have essentially different properties. Assembly planning begins in analyzing the possibilities of assembly with a given crane. This is called technical aspect of crane selection. Cranes that meet the technical criteria are then analyzed in terms of other criteria related to the effectiveness of their use on the construction site. The article presents the assessment of the selection criteria and the method of crane selection itself. Surveys conducted among construction managers and planners in Polish companies dealing with assembly works allowed to determine the significance of the selection criteria. For this purpose, an example using SAW (Simple Additive Weighting) and FSAW (Fuzzy Simple Additive Weighting) methods was presented. They also allowed to propose a technique for determining preferences in the use of selected construction cranes. The aim of the research was to increase the usability of computer applications supporting assembly planning by acquiring expert knowledge for the initial selection of organizational solutions.
The study of liquid crystalline assemblies, with an emphasis on biological phenomena, is now accessible using newly developed microdevices integrated with X-ray analysis capability. Many biological systems can be described in terms of gradients, mixing, and confinement, all of which can be mimicked with the use of appropriate microfluidic designs. The use of hydrodynamic focusing creates well-defined mixing conditions that vary depending on parameters such as device geometry, and can be quantified with finite element modelling.We describe experiments in which geometry and strain rate induce finite changes in liquid crystalline orientation. We also demonstrate the online supramolecular assembly of lipoplexes. The measurement of lipoplex orientation as a function of flow velocity allows us to record a relaxation process of the lipoplexes, as evidenced by a remarkable 4-fold azimuthal symmetry. All of these processes are accessible due to the intentional integration of design elements in the microdevices.
The solution of planetary gear with simplifying technology using the same geometry of the sun gear and the central gear is already known. The authors decided to change this concept i.e. to design a planetary gear with the same geometry of satellite wheels, which cooperate with a sun gear and a central gear with different number of teeth. The structural solution of elements of the gear is analyzed taking advantage of computational technique. Geometrical dimensions are described for the sake of teeth correction. Calculations and structural solutions of this kind of transmission are shown in the article.
The paper proposes three multi-criteria decision-making (MCDM) methods for the selection
of an industrial robot for a universal, flexible assembly station, taking into consideration the
technical and performance parameters of the robot. Fuzzy versions of AHP and TOPSIS
methods as well as SMART were chosen from the variety of MCDM methods as they represent
different attitudes to analysis. In order to minimise the impact of the method applied on
the final decision, a list of results of the analyses has been developed and a final classification
has been made based on decision makers’ preferences concerning selected parameters of the
robot.
In the assembly industry, almost all components are outsourced or transferred to other
parties, in order to meet the need for supply. This is referred as outsourcing of production.
The outsourcing of assembly product components is based on a relationship model
between the contractor and the industry. However, there is no relationship or communication
pattern between the contractor or supplier and the assembler. Hence, in order to
accelerate line production and overcome problems with assembly components, the communication
path is shortened by providing a direct communication channel between the
assembler and the supplier or contractor, in order to communicate any problems that arise
during the assembly process by internal communication within the industry. The purpose
of this study is the design and development of a web-based software application electronic
data interchange (EDI) that can be used as a tool for communication between the assembler
and supplier. The EDI application provides formal communication between the assembly
industry and the contractor providing the components or parts needed in the assembly process.
The main purpose of using EDI technology is to help the assembler to communicate
the relevant documents to suppliers quickly, accurately and efficiently. The documents to
be communicated are in the form of reports or claims, and are related to non-conformities,
errors and component difficulties arising during the assembly process. This research novelty
is providing direct communication between assembly and supplier by using EDI application
that can give contribution in manufacturing area so it can accelerate the line production in
assembly.
The results presented here are twofold. First, a heuristic algorithm is proposed which, through removing some unnecessary arcs from a digraph, tends to reduce it into an adjoint and thus simplifies the search for a Hamiltonian cycle. Second, a heuristic algorithm for DNA sequence assembly is proposed, which uses a graph model of the problem instance, and incorporates two independent procedures of reducing the set of arcs - one of them being the former algorithm. Finally, results of tests of the assembly algorithm on parts of chromosome arm 2R of Drosophila melanogaster are presented.
The aim of this article is to present the design procedure for determining modification coefficients of toothed wheels of involutes planetary gear train with internal conjunction of teeth. It is possible to obtain a higher load-carrying capacity which depends also on correction coefficients. For example, we take into consideration a concept of planetary gears in which the teeth can be corrected, which allows better fatigue and contact surface strength. Two cases are considered when the namely zero center distance (without corrections) of the central and satellite wheels is the same or not, in relation to the zero center distance between the satellite and the sun wheel. Geometrical dimensions are described with regard to the technological teeth correction scope, and inequality restriction conditions are determined with respect to the ISO standards recommendations and the literature. The procedure can be applied to any other planetary gears with another kinematic connection of wheels.
In the two-sided mixed-model assembly line, there is a process of installing two single stations
in each position left and right of the assembly line with the combining of the product model.
The main aim of this paper is to develop a new mathematical model for the mixed model
two-sided assembly line balancing (MTALB) generally occurs in plants producing large-sized
high-volume products such as buses or trucks.
According to the literature review, authors focus on research gap that indicate in MTALB
problem, minimize the length of the line play crucial role in industry space optimization.In
this paper, the proposed mathematical model is applied to solve benchmark problems of
two-sided mixed-model assembly line balancing problem to maximize the workload on each
workstation which tends to increase the compactness in the beginning workstations which
also helps to minimize the length of the line.
Since the problem is well known as np-hard problem benchmark problem is solved using
a branch and bound algorithm on lingo 17.0 solver and based on the computational results,
station line effectiveness and efficiency that is obtained by reducing the length of the line in
mated stations of the assembly line is increased.