The work paper contains the experimental results concerning the mechanical properties of some varieties of vine grapes produced in Romania. It is presented the variation of the detachment force of grapes out of pedicel depending on maturation degree, the angle which it action the detaching force and the grape mass, and the crushing force of peel depending on maturation degree and grape mass.
The paper presents operating parameters determination for series heat exchangers in order to determine counter flow operation for maximum performance. If the sizing procedure suggests a nonstandard length heat exchanger, use the next larger size or consider using two shorter heat exchangers.
There are situations when the temperature difference between two fluids is big. Also, from technological and financial reasons, the construction materials for these two tubes of the heat exchanger are different. The paper presents the main problems which appear in design work as a result of this fact.
Heat exchangers represent an important part of the study matter of the students from Process Equipments Department. That is why the lab work must be very synthetic and concluding prepared, thus the students may resolve as many practical applications as possible in the shortest time. The authors present a solution for such a work lab.
The flexibility of nozzles in pressure vessels plays an important role in both piping flexibility analysis and vibration analysis and therefore it is necessary to analyze the radial flexibility of nozzles. The aim of the present paper is to analyze the flexibility of radial nozzles by considering the effect of transverse shear deformations and to discuss the difference between the results of the two theories.
The paper presents conclusions of theoretical research for shear deformations and bending moments, but only for well specified cross sections, when factors like that gyroscopic moment, axial force, torque are neglected. The author presents the influence of bending moment and shears force for critical speed and calculation relations for bending moment and shear force determination in any cross section. Considering all these relations it is to realize a specialized soft for determining of these factors.
The construction material choice depends on work regime parameters (pressure, temperature), on corrosion and erosion and on the cleanliness factor imposed upon the product. The paper presents an applicative research for tall towers to establish some economic variants depending on the quality of the material used in tall tower construction, element size, loads and working conditions.
This work tackles the study of longitudinal stability of road platforms movement for transporting no gauge equipments; hereabout type (1+2) axles. In the effected analyze it is considered the effect of the assembly weight, of the forces of inertia and of the ones due to wind action, when climbing the ramp and also when descending the slope. At the same time it may be considered or not the effect introduced by the dampers, tires and the road surface deformability over the movement stability in the earlier mentioned conditions.
Complementary and alternative technologies proposed provide then use of cereal and water mash (1:3 hydro module) and starch turning into simple sugars by industrial enzyme preparations and further processing by: Alcohol fermentation of fermentable sugars by yeast followed by recovery and refining of alcohol obtained; Syrup separation from glucose-dextrose, syrup purification and concentration for food purposes.
Results obtained during the experiments confirm the initial hypothesis that cereal processing, namely corn to produce ethyl alcohol and glucose-dextrose syrup can be optimized and rendered profitable by this technique using the latest generation of industrial enzyme preparation.
Both raw materials which originate from agriculture and same product which obtain after technologically operation (ex. breaking up, granulating etc.) it examine on separation process, process which has role to move away, from the base product, same impurity or to obtain the same product, but on size, form, color class etc.
In this paper is presented determination mode of floating speed for a particle, which is, obtain after breaking up operation.
Because of industry development and appearance of urban agglomeration have like result pollution of ambient medium.
Grinding it's a base activity in to unity of grist. Grinding represent operation unitary of reduction a geometrical dimension of particles, following action of working mechanism at grinding machines Because variety dimension of mechanical property, chemicals composition, grinding cereals it's characterized from big complexity.
Texture of feeding products it is one of important factors which conditioning appropriation qualitative at one product, especially the sensorial. Texture notion can be easy understand if it is examination at an interaction between human senses and mechanical property of feeding product.
The scope of the present paper is to present an automatization mode of a wine plant computation, using on this purpose the computation technique, respectively, the computer- assisted command automatization of the functioning process of the wine plant. So, in the first part of the paper, starting from the computation mathematical apparatus of the wine plant technological parameters, an application has been realized using Visual C++ 6.0 software for the computation and optimization of wine plant technological parameters. In the second part of the present paper, using two interfaces (a hardware interface and a software one), it has been realized an application of autmatization of wine production when four identical wine plants are computer-controlled and commanded, the scope of the application being the correlation of parallel functioning of these ones.
For theoretical study about determination of mixer productivity its take a mixture formed by cocoa mass, cocoa butter, glazing sugar and powder milk. The determination was realized theoretically including two work modalities: by one single element, alternately, to a productivity calculating relation, obtaining linear graphics and by variation of two component elements of productivity formula obtaining spatial graphics.
Vinegar is a product of acetic oxidation and it is well known since antiquity. Any product subjected to alcoholic fermentation can be accepted as raw material in vinegar fabrication together with other matters such as honey, sugar, syrup. Wine, beer, cider and ethyl alcohol are considered the main raw materials for vinegar fabrication. In vinegar fabrication, both white and red wines can be used. Wine, as raw material, must be completely clear, filtrated and preservative free. In our country, as in France, Spain, Italy, wine represents main raw material for vinegar fabrication.
We must consider certain factors like oxidizing temperature and environment when we choose the method an technology for vinegar fabrication.
This test has been performed for determining the way in which the coupling saddle ensures the mobility range according to R 55 ECE-ONU and it has included two types of tests: static and dynamic ones. The values of applied forces and the suitable displacements determined during the tests to various values of the number of performed stressing cycles are presented under the form of some force-time and displacement-time diagrams.
This type of tests have been performed in order to determine the resistance to rupture of a 20 HP tractor draw bar, after running a number of 2.000.000 cycles, in an accelerated rate, at amplitudes and frequencies established according to D 89/173/CEE. It has also been checked whether this type of bar ensures the mobility range required by the Directive, finally finding if there occurred any fractures, permanent deformations or visible exterior deteriorations.
In the paper are presented some aspects regarding aspects regarding the powering by vibration generators with rotation masses of the classifying plane sieves blocks. It is also analyzed characteristic positions of vibration mechanism in working process and is analytically determined the amplitude of blocks oscillations and the value of rotation mass for some existing machinery in the field.
The authors has developed an engine friction model in order to determine the instantaneous friction components at any crank angle during the overall engine response. The main friction components are the piston assembly, the bearing, the valve train and the auxiliares. The model includes new analytically derived equations for the friction components of the rotary valves train, the ring assembly and the bearing with mixed lubrication. The model takes into consideration the effect of temperature variations on the viscosity of the oil. The friction equations are based on theoretical calculations for hydrodynamic and mixed lubrication. They rely on Reynolds equation and dvnamic analysis. Simulation results are presented, which compared with experimental data indicate an accuracy of more than 98 per cent.
Development costs and turnaround times can be significantly reduced by using a combination of computational and experimental methods. That is why, simulation methods have become an indispensable tool in the Diesel engines development process. The hardest part in this process is the model conception. The authors had created the model using a specialized soft "SolidEdge", the analysis being developed using Finite Element Method due to the COSMOS/M soft. In addition to the F.E.M., simulation methods are increasing in significance. Numerical methods are also becoming increasingly important as a tool for the development of combustion system applications. These methods provide a better understanding of the processes occurring inside an engine, allowing to perform dedicated fine- tuning of the various processes and to investigate the impact this has on performance, efficiency and emissions.
The effects of rotation on penetrative convection in an annulus of fluid are studied numerically by finite difference method. The axisymmetric flows for fourteen sets of parameters are presented. It is found that rotation compresses the cell heights and increases the horizontal cell number in the r-z plane. The curvature of the container strongly effects die cell structure only at low rotation rate. The upper dynamical boundary condition have virtually no effect on the flow fields if the upper temperature is sufficiently high.
The process of condensation of vapors on a laminar, falling film of immiscible liquid is formulated within the framework of certain assumption for a laminar, two-film model. The numerical solutions are presented for a wide range of parameters, and it is observed that the dynamics of the falling film has a profound influence on the condensation heat transfer rates. The condensation heat transfer coefficient is found to be a function of the modified Graetz number, subcooling parameter, and the heat capacity ratio of coolant-to-condensate. Further, shorter liquid film lengths would yield considerably high condensation heat transfer rates in comparison with the Nusselt analysis.
A simple computational procedure is described for ascertaining the heat or mass transfer in laminar forced convection over a rotating body of revolution. The analysis is applicable to nonuniform surface condition and for fluids having a large or moderate value of the Prandtl (Schmidt) number. Examples are given to illustrate the usefulness of the analysis as well as to expose its limitation.
The paper described the physical relations between the stresses and a strain that appeals in the walls of a hydraulic mono-tube shock absorber. There are determined the displacemenl.slopc.stress.cutiing force and ring stress expressions versus the damping coefficient.
The paper presents the correlation functions and the spectral density of a random function as against its derivates that are relations of utility in the dynamic system’s study such the twin-tube shock absorber. There are determinate the response of mathematical waiting, the autocorrelation function response, the dissipation response, the spectral density response.
This paper is a study on the structure of the surface layer of a grinded plane workpiece. It establishes the time variation of the surface layer temperature field, the workpiece layer where the melting temperature is attained. It is possible, in this way, to know the maximum width of the layer where the fast austenite/martensite transformations are changing the material properties. The study also establishes the variation of the surface layer width as a function of time, feed velocity and grinding tool thickness.
A finite-difference numerical method has been adopted to generate flow patterns and heat transfer characteristics for laminar, steady-state, two-dimensional natural convection around a circular cylinder submerged in an unbounded Boussinesq fluid. The approach allows the use of nonuniform as well as uniform specified temperature and heat flux distributions over the cylindrical surface. Part of the results are generated for reverse convective flows with recirculation zones which occur when part of the cylinder is below the ambient temperature while the remaining part is above. The results for uniform temperature boundary condition are in good agreement with the experimental data and other solutions available in literature.
The paper describes the mathematical model for a kind of twin-tube hydraulic shock absorber. A description of a passive shock absorber and the analytical complexities of the oil flow are discissed. The oil compressibility and the entrapped gas in the oil are considered in the model. It is found that the problem-of-water fraction is increasing while the decreasing of the velocity system.
This paper describes a mathematical model for a kind of a mono-tube hydraulic shock absorber. For the development of the nonlinear analysis it is presented the oil flow during the compression phase. It is taken in account the oil compressibility and the entrapped gas in the oil. It is found that the problem-of water fraction is increasing while the decreasing of the velocity system.
The energy produced of the water fall is one the most pure; consequently, an ecological solution, preferring anywhere is possible to account the gravitational energy. The great cost price of investments are made up for in fact, of important time of exploitation of the hydro-electric plants, the cost price of maintenance is petty and for fuel are null. Today there is a high competition among he producing firms of turbines for to impose the most performance models. The solution which is proposed in this paper will improve the performances of Pelton turbine
This paper is the result of the documentation work about the fluoridation of water. The scientific world has different judgments about this problem and the final conclusions it isn't made yet.
The fluoridation of the water generated many discussions about the human body effects. Exists controversies between proponents that sustain the benefic effect of prevent tooth decay and detractors insisting in risks and damages to the health of some people.
The paper analyses the modifications of the adjusted parameter value (the pressure p2 at the reducer outlet) depending on the values Qc of the consumed flow rate. These modifications are analyzed in three distinct areas of consumption and concrete solutions for the phenomenon to decrease in the areas I and III are suggested, the critical area in which the operating of devices performs abnormalities. In the contents of paper, the qualities, which increase or decrease the phenomena, which should arise, are also analyzed.
The experimental research was made with the aim of optimization of the papain addition in the beer in order to achieve a beer with rich and stable foam, and an enhanced colloidal stability. Through the introduction of the papain in the beer, it is achieved the enzymatic hydrolysis of the proteins for the low molecular mass compounds, which are unable to form complexes with the poliphenols or the dimerical or trimmerical anthocvanin. An addition of 1 to 3 grams papain per one hectoliter of beer gives it an enhanced colloidal stability.
The experimental research was made with the aim of making the multiplication of the Saccharomvces carlbergensis beer yeast in laboratory phase and the pure cultures station, more efficient. Maintaining constant the aeration of the must, the multiplication rate of the yeast, the pressure, the stirring rate and the temperature, it can be optimized the time in which the must have to be added for the next phase of multiplication without the determination of the apparent extract.
The process of incineration of city domestic waste has in view the environment depolution under economic conditions, upon the revaluation of the resulted thermal energy The advantage of the procedure is the fact that the equipment for burning needs small surfaces and can be situated close to the locations, thus reducing a lot the transportation costs. The ashes resulted by burning can be kept by the burning gas by means of some adequate installations, therefore the polluted materials eliminated into the surrounding areas through chimneys having corresponding sizes are relatively small.
The addition of bran and additives, such as wheat germs, aimed at the quality and nutritive increase of the diet bread. An addition of wheat bran in the limits of 10-30% represents an economic solution by replacing the wheat flour. In order to obtain normal technological results it is sufficient: 5% yeast, 2% NaCl, 1.5 wheat germs.
Using soya flour in bakery products give a proteinic product by partial replacing of wheat flour. At the 6% content of the soy flour in the mix with wheat flour type 800, the baking dough could be realized at the 180°C and 33-35 minutes.
The paper package uses as raw material cellulose from resinous wood, obtained from the sulphate and sulphite procedure. The paper packages widely used in the food industry are to be found under the form of bags, boxes or 70/100 cm standard sizes.
The lignin resulted from the process of flocculation in acid environment from the sulphate waste waters, is a product with specific functional properties which can be used with the best results in the electrical and metallurgical industry and in the wood industrialization.
The lignin resulted from the process of flocculation in acid environment from the sulphate waste waters, is a product with specific functional properties which can be used with the best results in the electrical and metallurgical industry and in the wood industrialization.
Slaughtering and canning technological process have a pollution degree owing to the modification of the residual solutions' quality. The qualitative weight polluters are represented by organic compounds, as like: animal fats, soluble and insoluble proteic compounds, mineral compound of the singeing and skinning phases. The polluting degree having instability characters owing to biochemical altered process lead to the application of process and quantitative reduction of the polluters.
The research realized in the first stage of the included complex program of the theme regarding residual solutions that come from the slaughtering technological process showed the possibility of using lime and aluminium sulphate for the flocculation of the biodegrabile organic components. Lime and aluminium sulphate consumption depends on the concentration of the polluting components. For a steady residue the resulting efficiency was 75% at 100 ÷ 5 oC and 90% being organic substances.
This study goal was to estimate the potential of some forestry and pulping wastes-wood and bark dusts to liberate aromatic by products. The use of different chemical characterization methods specific for lignocelluloses has allowed an estimation of polymeric and aromatic composition of studied materials, especially with the determination of lignins contents (ADL and KLASON), with guaiacyl and syringyl monomers from uncondensed lignins quantified by thioacidolysis. The distributions of monomers have been proved to be a function of the starting materials type: dicotyledonous angiosperms and gymnosperms, excepting pine bark, present the highest potential precursors quantities (280-380 µmol/g). Pine bark seems to be very different comparing by monomer distribution with the wood; it contains mostly guaiacyl monomers and a little fraction of p-hydroxyphenylpropan (< 25%).
This study goal was to estimate the potential of some forestry agricultural wastes- grassstraws, maize stem, hemp, flax, especially with phenolic acids incorporated in graminaceous cell walls after alkaline hydrolisis. The use of different chemical characterization methods specific for lignocelluloses has allowed an estimation of polymeric and aromatic composition of studied materials, especially with the determination of lignins contents (ADL and KLASON), with guaiacyl and syringyl monomers from uncondensed lignins quantified by thioacidolysis. The distributions of monomers have been proved to be a function of the starting materials type: dicotyledonous angiosperms and gymnosperms, excepting pine bark, present the highest potential precursors quantities (280- 380 µmol/g). Pine bark seems to be very different comparing by monomer distribution with the wood; it contains mostly guaiacyl monomers and a little fraction of p- hydroxyphenylpropan (< 25%).Monocotyledonous angiosperms contains two types of sources: like native lignins, few condensed and phenolics acids from complexes [lignin- phenolic acid-polysaccharides].
This study goal was to estimate the potential of some industrial lignins (isolated lignins). The use of different chemical characterization methods specific for lignocelluloses has allowed an estimation of polymeric and aromatic composition of studied materials, especially with the determination of lignins contents (ADL and KLASON), with guaiacyl and syringyl monomers from uncondensed lignins quantified by thioacidolysis. The distributions of monomers have been proved to be a function of the starting materials type. P-hydroxybenzoic, vanillic and syringic acids, even they are easy liberated in alkaline medium, it can't be considered aromatic aldehydes precursors. In concordance with these results, the aldehydes can be considered precursors for correspondent acids, which can be formed by oxidative treatment. It can be observed that Kraft lignins from gymnosperms (Kraft and Indulin AT) contain mainly G units incorporated in P-O-4 structures and vanillin, in the same measure. Hydrolytic lignin (sugar cane origin) is formed principal, by p-coumaric acid and S monomers. The organosoluble lignins are constituted both G units and S units, which can be explained by the type of starting material (dycotyledonous angiosperms).
The oat flour represents an important cereal source used in mixture with wheat flour in order to obtain the dietetic bakery products, with small gluten content; an adding of 3 - 6 % oat flour can ensure the obtaining of dietetic bakery products with nutritive role accepted by the consumers.
One of the problems of the development and valorisation of cereal raw materials and by- products resulted from the primary processing is represented by the proper understanding of the quality requirements imposed for food products, of the functional potential of the basic structures of aliments, as means of satisfying the nutritional context. The wheat bran results as a by-product with interest for alimentary consumption, a by- product which imposes by its chemical composition: the content in cellulose, mineral components, vitamins from the B group, vitamin PP and E, protein components, sugars and fats.
One of the solutions regarding environment cleaning refers to valorizing bran, a by-product from the operation of wheat grinding, in obtaining baking products. The research programmed is conceived in the centre system, rotary compound of the second degree with four independent variables, using wheat bran in the first technological phase for obtaining dough. An addition of maximum 12% bran could be considered sufficient for achieving the baking products with optimum quality conditions.
Using bran in the composition of baking products represents a technical- economic solution with positive ecological implications. A bran addition of 12% doesn't influence in a negative manner the settled baking conditions: temperature of 160-200°C and duration of 33 minutes.
The paper present sources structure and pollution factors for water in technological process to sugar fabrication from sugar-beet. water pollution to sugar fabrication.
In this paper we present the technical demands, which stand to base of projection a mechanico-biological purification block station for domestic water, and the principal levels in projection of these.
In this paper we present theoretical aspect concerning specific mechanical energy of soil works, soil texture and determination methods of this.
Up to the present, analyses have shown that most of the elements in the periodic system are found in water. Most of them are contained in tiny quantities, so that they do not modify water quality. In Siret hydrographic basin, in laboratories of physicochemical, biological and bacteriological analyses, investigations are carried out to determine the quality of surface waters in rivers of I and II orders in slow and rapid flow. When it comes to slow flow, water quality is analyzed monthly in 36 sections of I order, and quarterly in 24 sections of II order. As to rapid flow, analyzes are daily made in 16 sections. These analyses were made between 1998-2001 and values for all gauges were established. As a result of the determinations established, important changes regarding the oxygen pattern (OP) and the mineralization degree (MD) stood out. The results regarding water quality are the first step in the control activity with reference to technologies of depollution.
The presence of water it is an indispensable condition in the apparition and development of life on earth. Water is the main element in sustaining the fields which are responsable for social and economical development of a country. The examination of me water quality in four control points on the Siret river, from biological and bacteriological points of view, established the affiliation of the river to the beta mazosaproba area. This fact is owing to medium level of organic pollution that overtakes the admitted limit during four years with 30%.
The paper presents some peculiar aspects of ion exchange behavior for a weakly basic anion exchange filter which is placed in a water demineralization plant. The paper analyses the way in which the weakly basic anion filter operates. Operating capacity has been calculated and the protecting role for post-connected strongly basic anion exchanger to organic fouling has been pointed out.
The selective collect action of the domestic waste correlated with the description of their chemical composition, may lead to certain and accurate appreciations from a technical-ecological point of view.
The growth of the selective collect of domestic waste has emphasized for the researched program in a city and industrial area located in the North of Moldavia, having a population of 120000 inhabitants, a weight of 70%, represented by paper waste (bags, carton boxes, waste sheets), to which we can add plastic and glass waste.
Out of the physical - chemical and bacteriological processes, which turn waste into an inert material a less quantity of polluting agents, leaching and fermentation gas must result. The values obtained for the chemical parameters of the leaching analyzed, produced sequence to the water percolation through the municipal solid waste mass out of the ecological deposit studied range within the limits prescribed by the laws in force.
The air is the main of our life. We need air, every minute of our life In our life time we breath for more than 500.000.000 times. The atmospheric pollution is a dynamic process from the point of view of numbers and types of emission sources but also the number, nature and noviciate of the pollutants. Atmospheric pollution gaseous substances are: NO, N02, S02, C02, CO, H2S. The analyses of the C02 and CO in the atmosphere are effectuated by gas chromatography. The analyze is effectuate in Bacau, in different aria and different hours. The method using is gas chromatography. This method permits the determination of concentration of CO and C02 exprimated ppm-g/m3 air The highest polluted area in Bacau is situated in the proximity of Margineni area. In the proximity of Bistrita River it was registered lowest concentration of CO and C02 this concentration is bellow maximal limit.