The Potential of Introducing Heat Pumps (HP) and Thermal Energy Storage for the Crucea Commune, Constanta, Romania Systems in Order to Enable the Decarbonization in Romania

This case study aims to analyse the market potential of heat pumps and thermal energy storage in Romania at the level of a small commune, Crucea from Constanța. It was carried out on the basis of interviews with the main decision-makers of the commune. During the study, documents regarding the thermal energy and electricity consumption of the main public buildings in Crucea have been analysed and field visits have also taken place. Documents such as the existing energy certificates of the buildings and their RLVs were also studied. It presents the structure of the thermal energy consumption of public buildings and analyses the data on the consumption and costs of thermal energy in order to reduce electricity consumption and the carbon footprint. The study proposes technical solutions based on integrated systems with heat pumps and thermal energy storage, customized for each public building analysed

The influence of the chelating/combustion agents on the structure and magnetic properties of zinc ferrite

AbstractThe present study is reporting the influence of the chelating/combustion agents on the magnetic properties of Zn ferrite. Six chelating/combustion agents, citric acid, egg white, tartaric acid, glycine, glucose and urea, were used to obtain monophase zinc nanoferrite via a sol-gel auto-combustion method. The samples were subjected to a comparative study of structural features and magnetic properties by means of infrared spectroscopy, X-ray diffractometry, scanning electron microscopy and vibrating sample magnetometry. Significant influence of fuel and combustion mode was observed in the magnetic behavior of as-obtained samples. Values of the structural parameters were discovered to vary as a function of fuel choice, and to obtain crystallite size between 38 and 62 nm, inversion degree between 0.239 and 0.807, lattice parameter between 8.4125 and 8.4432 Å. The optimization of sol-gel method synthesis of zinc ferrite nanoparticles by chosing the appropriate fuel is providing structural and magnetic properties of zinc nanoferrite as potential materials to be used in biomedical applications

The energetic load smoothing along the rack tool cutting edge in toothing process

The method of generating the gear tooth with a rack tool is applied on MAAG machine tools. Their specific cutting scheme leads to an irregular energetic loading of the tool cutting edge, during the rolling process. In this paper, we present a new method for analyzing the energetic load along the cutting edges of the rack shaped cutter, based on graphical modelling of the cutting process performed in CATIA. The energetic load smoothing is proposed to be obtained by finding an appropriate variation law for the circular feed communicated to the workpiece by toothing machine kinematical chain, during the rolling motion that permanently respects the rolling condition established between the centrodes attached to both tool and workpiece. A numerical solution in a concrete case of analysis is also included

Detached chip smoothing during involute gear slotting in relation to generated tooth features

The problematic concerning the generating process uniformity, in the specific case of machining involute gear teeth with a rack shaped cutter provided by a single tooth is one of the notable challenges from gear teeth machining domain. In previous work, it has already been presented a solution of this problem, based on a graphical application in CATIA. The solution involves the modification of enveloping process ongoing, such as the circular feed motion takes place with variable speed. The variation law of feed motion speed that should be followed for smoothing the detached chip area is, obviously, different for each gear-type specific case. This paper is aiming to study the influence of generated tooth features onto this law form. Graphical and numerical applications addressing different cases of teeth numbers for the generated gear are presented and analyzed

Detached chip smoothing during involute gear slotting in relation to generated tooth features

The problematic concerning the generating process uniformity, in the specific case of machining involute gear teeth with a rack shaped cutter provided by a single tooth is one of the notable challenges from gear teeth machining domain. In previous work, it has already been presented a solution of this problem, based on a graphical application in CATIA. The solution involves the modification of enveloping process ongoing, such as the circular feed motion takes place with variable speed. The variation law of feed motion speed that should be followed for smoothing the detached chip area is, obviously, different for each gear-type specific case. This paper is aiming to study the influence of generated tooth features onto this law form. Graphical and numerical applications addressing different cases of teeth numbers for the generated gear are presented and analyzed

Determination of the Depth of Cut via Surface Integrity

The present paper continues the authors’ research in machining process optimization, including the direction of machining parameters optimization. The paper develops an innovative method, via surface integrity, for determining the technological route and the related depths of cut, with respect to machining front faces of cast iron parts. For correctly establishing the depths of the cut, the errors that appear within surface and subsurface layers during the casting process, as well as during machining, must be gradually eliminated. These errors make it necessary to consider the concept of surface integrity. This paper presents the modality of integrating the components of surface integrity into the depth of cut. For the practical use of this method, a new software tool based on a series of mathematical models and a small database was conceived. A case study illustrates how the method is applied and the software tool used to solve a specific application in the case of a belt pulley

The energetic load smoothing along the rack tool cutting edge in toothing process

The method of generating the gear tooth with a rack tool is applied on MAAG machine tools. Their specific cutting scheme leads to an irregular energetic loading of the tool cutting edge, during the rolling process. In this paper, we present a new method for analyzing the energetic load along the cutting edges of the rack shaped cutter, based on graphical modelling of the cutting process performed in CATIA. The energetic load smoothing is proposed to be obtained by finding an appropriate variation law for the circular feed communicated to the workpiece by toothing machine kinematical chain, during the rolling motion that permanently respects the rolling condition established between the centrodes attached to both tool and workpiece. A numerical solution in a concrete case of analysis is also included

Machining Parameters Optimization Based on Objective Function Linearization

Manufacturing process optimization is an ever-actual goal. Within this goal, machining parameters optimization is a very important task. Machining parameters strongly influence the manufacturing costs, process productivity and piece quality. Literature presents a series of optimization methods. The results supplied by these methods are comparable and it is difficult to establish which method is the best. For machining parameters optimization, this paper proposes a novel, simple and efficient method, without additional costs related to new software packages. This approach is based on linear mathematical programming. The optimization mathematical models are, however, nonlinear. Therefore, mathematical model linearization is required. The major and difficult problem is the linearization of the objective function. This represents the key element of the proposed optimization method. In this respect, the paper proposes an original mathematical procedure for calculating the part of the objective function that refers to the analytical integration of the tool life into the model. This calculus procedure was transposed into an original software tool. For demonstrating the validity of the method, a comparison is presented among the results obtained by certain optimization techniques. It results that the proposed method is simple and as good as those presented by the literature

End mill tool profiling by CAD method

296-302<span style="font-size: 9.0pt;mso-bidi-font-size:10.0pt" lang="EN-US">In orthopedics a lot of specialized tools and reconstructive elements are being used. Most of these tools are bounded by helical surfaces, significantly different from those used in similarly constructions with general character. The characteristics of these elements are defined by the structure and the composition of the material where the reconstructive elements are mounted, namely the bone. Hence result the necessity to imagine new fastening elements on screw type, characterized by a specific form. This paper presents a method developed in a CAD environment for profiling tools bounded by the revolution surfaces of the specifically helical drill used in the orthopedic reconstruction surgery. On the other hand, the surgery tools, like drills, must have cutting tools distinct from those used in the inorganic materials. Their shape has to assure a minimum heating of the machined material and to allow a good ejection of the material resulted from processing. An analysis of the cutting zone of the helical drills is also made by graphical methods, based on the CATIA design environment. A profiling algorithm of the end mill tool for generating helical surfaces with imposed axial section is also defined. </span