<abstract>
<title style='display:none'>Abstract</title>
Bridges are always subjected to different types of loads, which can be divided into three big categories: vertical loads, transversal loads, and longitudinal loads. The primary function of a bridge is to have good performance under heavy loads represented by cars, trucks, trains and sometimes tanks. The aim of this paper is to provide an overview regarding types of loads that can appear on bridges with the main focus on loads generated by vehicles. This description will contribute to our future studies. We aim to develop future research and perform different types of stress calculations on the Octav Băncilă passage from Iași (Romania). Finite element analysis will be conducted on vehicle loads generated by trucks, which act on the bridge structure, simulating different loading scenarios. Based on the values of the stress calculations, we will highlight dangerous sections and take measures to enhance the reliability degree of the analyzed bridge.
</abstract>

Loads on Bridges - Overview

<abstract>
<title style='display:none'>Abstract</title>
This paper intends to introduce a new approach in cycloidal reducers design. The usual design uses rotary pins as teeth on the ring gear (or stator as well) and an appropriate conjugate profile on the cycloidal disc (or rotor as well). This study proposes a new approach: to use rotary cylindrical pins as teeth on the rotor and an appropriate conjugate profile on the ring gear (or cycloidal ring) according with the rules of gearing. The main achievements of this paper focus on the synthesis of 2D internal profile of the cycloidal ring in transverse section. Some theoretical achievements and computer aided simulation results are briefly presented in this paper. This 2D profile is useful mainly for cycloidal reducer computer aided simulation and optimization but also for manufacturing purposes (by contour milling on CNC machines).
</abstract>

A Study of 2D Profile for a Cycloidal Ring Used in a Cycloidal Reducer

<abstract>
<title style='display:none'>Abstract</title>
This paper proposes a simple approach on the synthesis of the 2D profiles for the rotors of cycloidal reducers. A 2D rotor (or cycloidal disc) profile (as a complex closed curve) can be defined (as an alternative to the strictly mathematical definition) as the internal bordered envelope of the family of 2D profiles of the stator (or ring gear) obtained with the stator movable (for at least a completely rotation) around the fixed rotor (or planetary gear) by respecting the gearing conditions inside a cycloidal reducer. The more 2D profiles of the stator are used the more accurate definition of 2D rotor profile is obtained. The finding of <italic>x</italic>, and <italic>y</italic>-coordinates of the points involved in the description of this 2D rotor profile is by far the most complicated problem to solve in the manufacturing of this type of reducer, the behavior and performances of the cycloidal reducer drastically depends by the accuracy of this profile. The results of this study can be easy applied in practice.
</abstract>

A Study on the Synthesis of 2D Profiles for Cycloidal Discs Used in Cycloidal Reducers

<abstract>
<title style='display:none'>Abstract</title>
Composites occupy an important place in high-end industries due to their superior characteristics compared to traditional materials or individual constituent materials.
The work focuses on the FEA analysis of composite materials with CFRP carbon fibers with polymer matrix subjected to tensile and shear loads, an important subject of study in the field of engineering. The analysis using the finite element method is a real help by simulating the materials in different conditions. Due to their advanced properties, composite materials can be tested and optimized before being used in production. This can reduce the need to make prototypes and testing multiple times. The aim is to increase productivity and eliminate excess waste, an important process that is the basis of all industries today.
Modified butterfly-type specimens were used in these research studies to be tested on the Arcan device. The simulation conditions were similar to a tensile and shear test conducted in the laboratory, considering a material without cracks or other impurities in its structure and utilizing mechanical properties provided by software Ansys for unidirectional carbon fiber and epoxy-reinforced matrix.
</abstract>

FEA of Carbon Fiber Reinforced Polymer Subjected to Tensile and Shear

<abstract>
<title style='display:none'>Abstract</title>
Simulations of water flow in open-channel in the presence of an air–water interface are performed to examine the velocity distribution profile in deep and along of the channel. The simulations are made for a channel with glass walls.
</abstract>

Simulating Water Flow Through a Hydraulic Channel Using Ansys

<abstract>
<title style='display:none'>Abstract</title>
In the paper are present a practical procedure involving the determination of crack propagation rate using da/dN software. The procedure of the tests, the presentation of the da/dN software and its operation, the hypothesis and the conditions of the experiment and the results obtained from the experiment were presented. The determination of the yield strength and elastic characteristics was used, in which the steps for carrying out an experiment in the laboratory were explained. This was carried out by choosing the materials, presenting the apparatus and the specimen to be analyzed, and the results obtained from the experiment. It should be mentioned that da/dN software was used to obtain the results. The paper illustrates the dependencies between crack growth and the number of loading cycles, demonstrated by two experimental methods. The theoretical part underlying the two experimental methods, the calculation relations used, the importance and role of the da/dN software in their realization are discussed, and the conclusions of the study are presented at the end.
</abstract>

Determination of Fatigue Crack Propagation Rate by Two Methods

<abstract>
<title style='display:none'>Abstract</title>
A considerable number of prosthetic medical devices for amputees are known. These devices do not fully replace the biological functions of the lost limb following lower amputations. In the case of pediatric patients, the problem is even more serious, as they are growing, it is necessary to regularly adjust the height of the prosthesis. Otherwise, a discrepancy occurs in the length of the limbs, that changes the center of gravity of the body of the prosthesis wearer, leading to related and sometimes serious pathologies. Currently, there are only classic, passive modules for adjusting the height of the prosthesis, but which are adjusted manually with low precision and extensive work. The present work contains the method of digital control of the prosthesis that can ensure the motorized height adjustment of the patient’s lower limb. The results obtained from the experimental tests are presented, which indicate that this type of concept is feasible from a biomechanical point of view and can be a technical advance in the market of prosthetic medical devices addressed to the pediatric area.
</abstract>

dimitrie-cristian.fodor@student.tuiasi.ro

Testing a New Concept of a Self-Adaptive Transtibial Prosthesis

<abstract>
<title style='display:none'>Abstract</title>
In business, quality has demonstrated to be troublesome to characterize. Numerous people relate quality with a few degrees of enormity or common prevalence, whereas others see it as basically the nonattendance of fabricating blemishes. The American National Benchmarks Established (ANSI) and the American Society for Quality Control (ASQC) built up the official definition of quality in 1978.
Concurring to the overview, either the administration and parent company inside or the client remotely give these businesses with the inspiration to execute quality control. Due to a need of specialized understanding, the businesses are not utilizing six sigma strategies or capability ponders. The capacity to degree item determination satisfaction, the comfort of utilize of the procedure, and the capacity to address squeezing quality and efficiency issues are the three contemplations that these companies consider when choosing a quality control approach.
</abstract>

Theoretical Research into Quality Impact on Manufacturing Organizations

<abstract>
<title style='display:none'>Abstract</title>
This paper introduces a new approach in instantaneous angular speed monitoring using a two-phase <italic>n</italic> poles AC generator as sensor. A two-phase <italic>n</italic> poles (<italic>n=50</italic>) stepper motor plays the role of sensor. Its rotor is firmly connected to the rotary part whose instantaneous angular speed should be measured. The sensor produces two identical sinusoidal EMF (electromotive force) signals (theoretically shifted with <italic>π/2</italic> radians) with the same periods <italic>T</italic>. This paper proposes to use the mathematical product of the numerical descriptions of these EMF signals in order to define a new EMF signal with a period <italic>T/2</italic> whose analysis allows the determination <italic>of 4·n=200</italic> samples of instantaneous angular velocity on each full rotation. Each period of this new EMF signal (with an overlap of a semi period) is involved in the description of the instantaneous angular speed. In this way, the sensor is virtually converted in a single-phase <italic>2·n</italic> poles (2·<italic>n=100</italic>) AC generator. The experimental results confirm the validity of this approach.
</abstract>

Improving Instantaneous Angular Speed Monitoring by Means of Sinusoidal EMF Signals Delivered by a Two-Phase <italic>n</italic> Poles AC Generator Used as a Sensor

<abstract>
<title style='display:none'>Abstract</title>
Bimetals are usual designed by use of analytical formulas based on the beams theory from the Strength of materials. The paper presents a FEA study of a bimetal beam with two layers: Invar and Copper. The sensitivity of the thickness of layers was considered for: equal layers thickness, thickness calculated with a formula recommended in classical literature for optimizing the deformation (based on the Young modulus of the components) and several intermediary thickness values. For the case of the equal layers thickness the results from FEA and analytical formulas are compared. For all the studied models stress and deformation components from the longitudinal symmetry plane area are presented by comparison. The CAD and FEA models were developed within the FreeCAD open-source package.
</abstract>

Some Aspects on the Elastic Behavior of a Bimetal Considering the Sensitivity of the Thickness of the Layers

<abstract>
<title style='display:none'>Abstract</title>
This paper presents a numerical method for solving the two-dimensional Laplace equation in curvilinear coordinates using a finite difference scheme. Laplace equation is a differential equation used to describe various physical phenomena studied within different branches of engineering. The two-dimensional Laplace equation has analytic solutions only for simple shaped domains and simple boundary conditions (first and second kind). Even so, the results are usually complicated to interpret and use. The present paper proposes a method to solve the equation for domains bounded by complex inner and outer curves. The boundary curves are defined by a set of points from which the equations of curves are approximated by using Fourier series. The domain is generated by blending the two curves using a blending function. The results are a set of continuous parametric equations which are defining the domain in angle and radius variables. Following a method presented in the literature, the Laplace equation is transformed from Cartesian coordinates to curvilinear coordinates, as the Fourier series is easily differentiable. Next, the new Laplace equation is approximated using the finite difference method and a MATLAB code is developed to solve the system of linear equations using successive over-relaxation method (SOR). The presented method is used to simulate steady two-dimensional heat conduction in a polygonal shape domain, with uniform and non-uniform Dirichlet boundary conditions. Results are analyzed in order to determine the model’s precision, speed and convergence criteria.
</abstract>

gabriel-dumitru.tcaciuc@academic.tuiasi.ro

Finite Difference Method for Solving the Two-Dimensional Laplace Equation in Curvilinear Coordinates

<abstract>
<title style='display:none'>Abstract</title>
Motivation in the workplace is a topic of interest for organizational managers. This article provides readers with systematic ideas from the literature on the importance of consistently motivating human resources.
Within the article, motivational theories in organizations will be analyzed through a review of the specialized literature. This analysis shows that the level of satisfaction experienced by an employee reflects in their desire to work. In other words, a strongly motivated employee will achieve better performance at work.
The article highlights motivational theories developed by specialists that help organizations to understand and determine the needs of human resources.
This way, employees can be properly stimulated according to their own needs and expectations, recording maximum performance, while also helping to achieve organizational objectives. In addition, the article brings to the attention of readers news regarding the necessity of organizational potential of companies, as well as a workforce in accordance with the requirements of daily activities.
</abstract>

Perspective on the Motivational Theories in Organizations

<abstract>
<title style='display:none'>Abstract</title>
Actually, the Fused Deposition Modelling is one of the most popular Additive Manufacturing technology among ordinary users because of the low-cost equipment and the great variety of materials available on the market. Even many users mostly use it, not all of them are adopting the advanced parameterisation of the processes, preferring default set-up with a small interference over the basic parameters such as layer height, number of perimeters, and infill. Regarding the nozzle diameter, several advantages and disadvantages are implied by the relation of printing time-surface finish. Usage of large-diameter nozzles present advantages such as reduced manufacturing time, low risk of clogged nozzle, and more. Those cause worse resolution for small features and support structures to be more challenging to remove. By adjusting the nozzle parameters such as extrusion width and extrusion temperature, it was possible to obtain similar effects with a regular nozzle. This research’s main goal was to investigate if there is imperative the usage of larger-diameter nozzles for speeding up the manufacturing process, or the same effect can be achieved by using nozzles with a smaller diameter. In the end, we managed to reduce the manufacturing time to half compared to the initial time.
</abstract>

Influence of Nozzle Parameters in 3D Printing Under the Manufacturing Time

<abstract>
<title style='display:none'>Abstract</title>
The bond-graph method is used for finding the equations which describe the systems dynamics, by analysing the way of power transmission from the source to the working elements. When the energy storage elements I and C are in integral causality, the number of state equations equals the number of these elements. If there are also energy storage elements in derivative causality, the system contains a number of differential equations equal to the number of energy storage elements in integral causality and a number of algebraic equations equal to the number of energy storage elements in derivative causality. The work presents a new method for finding the system of differential equations for mechanical systems with one degree of freedom, starting from the original system which contains both algebraic and differential equations.
</abstract>

A Method to Find the Differential Equations from the Bond Graph Containing Inertial Elements in Derivative Causality

<abstract>
<title style='display:none'>Abstract</title>
The process of energy conversion of incidental solar radiation to useful electric energy in photovoltaic (PV) panels is affected by several external factors, of which panel operational temperature is of utmost importance. The present study attempts to clarify the theoretical components of thermal behaviour of PV panels, by taking into account the detailed structure of thermal resistances of panel layers. The numerical model, developed from the theoretical analysis, shows a good agreement with experimental data provided by manufacturer for the photovoltaic panel Suntech STP280 - 24/Vd.
</abstract>

Theoretical Model for Photovoltaic Panel Thermal Analysis

<abstract>
<title style='display:none'>Abstract</title>
There are situations where parts manufactured by 3D printing processes must have a high abrasion resistance. To conduct experimental research on this subject, relatively simple test equipment for abrasive wear of pin-on-disk type was designed and materialized. The test pieces from the research material were pressed with known forces on the surface of a rotating abrasive paper disk. The test pieces were made of polyethylene terephthalate PET and polyethylene terephthalate carbon fiber reinforced PET CF15. As output parameters, the speed of decreasing the mass and the length of the test piece were used, respectively, for predetermined test durations. An experimental Taguchi L8 program was used, with 7 independent variables at two levels of variation. The experimental results were mathematically processed determined empirical mathematical models of the power function type. It was found that the strongest influence on the values of the output parameters was exerted by the average travel speed and by the granulation of the particles incorporated in the abrasive paper disk.
</abstract>

Abrasion Resistance of Plastic Parts Manufactured By 3D Printing

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Bulletin of the Polytechnic Institute of Iași. Machine constructions Section

Buletinul Institutului Politehnic din Iași. Secția Construcții de Mașini

 Machine Construction section, as part of the Bulletin of the Polytechnic Institute of Iasi founded in 1946, appears as an autonomous publication since 1950. Currently, it is...

 Machine Construction section, as part of the Bulletin of the Polytechnic Institute of Iasi founded in 1946, appears as an autonomous...

Bulletin of the Polytechnic Institute of Iași. Machine constructions Section

Buletinul Institutului Politehnic din Iași. Secția Construcții de Mașini

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