There is one fact that lead composite material to be a unique material among others. Its properties could be settable or flexible with arrangement of composition, orientation and production procedure. Meanwhile other materials seemed to have fixed set after fabrication. Nowadays, one of the widely developed structural composite is polymer based composite with inorganic reinforcement. It is useful in automotive or aircraft component because reasonable strength and much lower density compare to metal. In this study, e-glass fibers were manually laminated with polyester resin in open die using brush. This method is widely known as hand lay up. Fibers were set in stacking sequences of 0 o , 90 o , and 0 o , means a fiber is in perpendicular direction to its neighbor fibers. After complete dried up, composite panel is cut of accordingly to ASTM standard for tensile and compressive testing specimen. In order to examine hole effect, center of gage length specimen was drilled off. Namely, specimen will be distinguished as no hole specimen and open hole specimen. Results showed tensile strength of 200.58 MPa and 155.22 MPa, compressive strength of 335.73 MPa and 254.1 MPa, for no hole and open hole specimen respectively. Introducing open hole reduces mechanical strength of composite both tensile and compressive. It could be mechanical consideration for safety design of material composite application. Failure mechanism of composite is also influenced by existence of open hole. When no hole specimen will experience failure at near to grip (LAT), open hole specimen has fracture line propagate from hole into width (LGM).
The present paper is concerned with experimental study of thermal performance of a Photovoltaic/Thermal (PV/T) tray dryer. The PV/T tray dryer considered consistes of a solar cell module of 100 W P integrated with a cabinet dryer. The cabinet dryer is covered with tranparent UV plastics allowing direct heating from solar radiation The ccoling air of the solar cell is used as drying medium and circulated by solar cell powered DC fans. The experiment was performed under no load condition at different weather conditions, i.e on a cloudy day and a clear day. During the experiment, the daily average solar radiation and ambient temperature are respctively 324,7 W/m 2 and 26,5 o C (cloudy day) and 727 W/m 2 and 27,9 o C (clear day). The maximum air temperatures attained in the dryer chamber are 34,4 o C (cloudy day) and 40,5 o C (clear day). There is air temperature variation among the trays, however the variation is insignificant, only at the order of 1-3 o C.
Power House Division (PHD) is one of the divisions that is part of PT. ABC. As an electrical energy supplier in XYZ area, Power House Division consist of four Power House, which each Power House has several engine. The first Power House (PH 1) consist of two Diesel engine Generator (DG) and one Gas Turbine in the second Power House. The third and fourth Power House consist of seven Diesel engine Generator. To keep the engine performance stable that is produce maximum power and prevent unknown damage that it make engine trip then the overhaul activity done. overhaul activity is carried out the process of replacement and recondition of spare parts of all parts of the engine. The recondition process is done in the cylinder head. Cylinder Head is an important component of a machine function as a combustion place and as an inlet and airway. There are long stages done In the process of recondition cylinder head from the demolition of cylinder head components to the re-installation of these components. There is a cylinder head that has crack, so it can not be recondition. It should be replaced with a new cylinder head. The machining process is used recondition cylinder head. They are Cutting, Lapping, and Grinding. In the pocket cylinder head, the recondition is found that it has a rust so that the size of the pocket and oversize that it has sticks around the pocket. Grinding process performed on uneven parts of valve.
A main drive is an important mobilizing motor component in a raw mill. Due to the extremely condition of constant operation of the raw mill results in failure of the main drive. This disturbs the raw mix intake and halts the next processes. In order to observe and diagnose the cause of failure on the main drive, it is important to conduct a maintenance. The Predictive maintenance technique utilized in this research is the vibration analysis technique. The measuring process of the vibration is conducted through the use of transducer velocity in radial and axial directions on the drive and non-drive components of the RIM03 motor and the symetro gear. The vibration, spectrum, velocity, and speed of rotation are analyzed in the x-Viber. Based on the vibration measurement data, the root cause of vibration can be analyzed through spectrum velocity. In this research, the critical result is found at the LS symetro gear. The occurred problem on the LS symetro gear is caused by misalignment shaft on the symetro gear connecting to gear pinion. The solution which can be applied is heat treatment to the shaft, therefore misalignment can be reduced.
The air conditioning machine commonly used is air conditioning system with a vapor compression cycle. The use of air conditioning machines consumes more electrical energy than other household appliances. In this study, the addition of the water mist method in evaporative cooling system with variations of distance of 20 cm, 40 cm, 60 cm so that the energy consumption of split type AC (Air Conditioning) of machines is more efficient. The results showed that the pressure of the condenser using water mist was lower 48 Psig than the pressure of condenser with a cooling load of 2000 W, and lower by 34 Psig of the pressure of condenser without the cooling load. Meanwhile the temperature of the air entering the condenser (Tout) after using a water mist has lower temperature than without the water mist, therefore it can save electricity consumption in the compressor. The temperature of the lowest inlet air of the condenser reached at the use of water mist with a distance variation of 60 cm was 28 ℃. And the relative humidity (RH) relatively decrease at the exit of the condenser using water mist with distance variation of 60 cm length was 59.6%. The compressor power decreased lower using a 60 cm distance water mist of 0.52 kW compared to without using a water mist with a 2000 W load of 0.56 kW. So that COP using water mist higher about 5.24 than without a water mist of 4.72. The highest COP was obtained using water mist at a distance of 60 cm
Electrolysis is a method used to describe the composition of air. electrolysis converts air bonds (H2O) into its constituent compounds flammable Hydrogen and Oksigen which help the combustion process. Water electrolytic devices are called HHO generators, HHO generators use pure water electrolysis, the results of the meeting between H2 and O2 will be used as alternative fuels in meeting renewable energy needs. This research uses a HHO generator. Testing the performance of the HHO generator is done experimentally on a laboratory scale. The first stage is making a dry type HHO generator using SS316L plate. The size of the plate is 70 mm x 70 mm, the center of the plate is punched Ø 12 mm, the top and the bottom of the plate are perforated Ø 10 mm. The HHO generator consists of 5 cells and 4 neutral plates for each cell by agreeing 5, 7 and 9 grams of KOH for 1 liter of distilled water. The results of the production of HHO gas produces a large amount of H2 and O2 which flows in units of minutes at a volume of 500 ml. HHO gas production parameters will depend on current, power and efficiency will increase from each of the above variables. Measurements use special measurement tools to distinguish which are quite significant
Bathtube curves are often used by reability engineers to describe the life of a product's population. This graphical representation of the bathtube curve can be divided into 3 phases. The first phase of the curve is infant mortality failure which is characterized by decreasing failure rate. The second phase is normal life or useful life which the failure rate is aproximately constant. Finally, the third phase is wearout failures and it is assumed that failure rate increases. To observe the running-in periode, a pin on disc test was conducted based on the ASTM G99 standard, where the disk rotates and the pin is loaded. So that the relative motion occurs between the pin and disk with a point contact. Between the surface of the disk and the pin is lubricated with several types of lubricant. Tests carried out for 30 minutes with a time interval of data collection every 6 minutes. From the results of tests, in the phase of running-in periode shows that the wear rate in the first 6 minutes was very high and it tends to decrease exponentially. Lubricant could influence the wear rate and surface texture of the discs in the running-in periode as well.
Les boulets de broyage ou de concassage sont des elements de broyeurs utilises dans les cimenteries; ils exigent une resistance a l’usure elevee sous l’action de produits abrasifs lors de la transformation de la roche en fines particules de taille inferieure au millimetre. Les traitements thermiques constituent une etape essentielle pour l’elaboration du boulet. Ils permettent d’obtenir des duretes et une resistance a l’usure convenables. Les analyses structurales et microstructurales par diffraction X et microscopie electronique a balayage permettent de comprendre leurs correlations. Dans cet objectif, nous avons etudie l’influence de quelques facteurs determinants dans ces traitements. Les facteurs consideres dans le present travail sont : la temperature d’austenitisation (950 °C et 1050 °C), la severite du milieu de trempe (refroidissement a l’air ventile et a l’huile) et le diametre des boulets (boulets de diametre 50 et 70 mm). Les resultats obtenus ont revele la presence de carbures de type Cr7 C3 repartis dans une matrice martensitique ou ferritique et que le taux de l’austenite present dans les boulets trempes a l’air ventile est inferieur a celui des boulets trempes a l’huile. La temperature d’austenitisation et la taille des boulets influent sur la trempabilite. En effet, l’ecart de durete entre la surface et le cœur des boulets de diametre 50 et 70 mm chauffes a 1050 °C, refroidis a l’air ventile et a l’huile, est plus important que celui des boulets correspondants chauffes a 950 °C. Une augmentation de la taille des boulets conduit a la diminution de la trempabilite notamment les boulets de diametre 70 mm chauffes a 1050 °C.
This article presents the last improvements of Dassault Aviation in the field of aero-acoustic loads and vibrations resulting from the in-flight opening of a drone's weapon bay. Within the context of the nEUROn programm, Dassault Aviation computes the aero-acoustic loads applied on the weapon bay panels and analyses their effects in term of acoustic fatigue and equipment's vibrations. Due to the frequency band involved and the aero-acoustic loads complexity, new methodologies and tools have been developed to predict the dynamic behavior of the structure in the middle frequency band field. Those methods have been validated and their limits identified through a wind test tunnel. The real application of this work during the development phase is pointed at through: on the one hand, the acoustic fatigue impact on the structure design, on the other hand, the vibrations specifications for equipment qualifications. This last point is, for the first time, entirely computed with numerical simulations by Dassault Aviation. Finally, the first confrontations of the specified environment with the equipments behaviour during qualification tests lead to discuss the method and consider prospects and improvements.
What environmental constraints will materials have to face in the future? Can current measurement tools like LCA (Life Cycle Analysis) support the choices of material and adapt to these constraints to pave the way to a sustainable world? Are there some alternative or complementary approaches to enhance the quality of information for decision makers? The aim of this article is to provide answers to these three questions. The society of tomorrow, in the second half of the 21st century, will be a society where the circular economy will play a more important role and thus will help reduce materials waste. This is a critical aspect of sustainability. To get there, the decisions have to be enlightened and fair, because the decisions (or non-decisions) made today shape the world that future generations will have to manage. Furthermore, Lord Kelvin used to say: "what you can't measure, you can't improve". Therefore, these decisions have to be supported by measurement tools that will properly capture the stakes of reuse and recycling at the end of life of products. Today, LCA is the common tool used to address this matter. However, the present article has shown that LCA cannot incorporate the whole complexity of sustainability. LCA is good at considering micro-scale issues, comparing one solution with another, in a static approach. How can it give right directions to decision makers in order to support the vision of a circular economy? The application of different standards showed that it is not easy at all and that recycling product at their end of life are not rewarded equally and sometimes not promoted at all. Therefore rebound effects leading to contradictory decisions may occur. LCA alone is not enough to make enlightened decisions. It should be complemented by other methods. This was proposed in the last part. Based on the IPAT equation, this approach tries to capture different aspects that are not addressed properly by LCA, due to the fact that the functional unit is too restrictive, that the time dimension and prospective approach should be more integrated, and that it should enlarge the scale of the analysis to the macro-economy and the socio-economy. It should also recognize that the efforts have to be shared by different players including material industry and manufacturers, policy makers and society in general. As a general conclusion, we are convinced that tomorrow's society will recognize the value of materials that are recyclable and reusable, like steel has been for many decades. But there is still a clear need to addressing, in research and development, the improvement of the metrics, combining social, environmental and economic assessment, so that the sustainability value of materials is properly measured. These are the objectives of the Sovamat Initiative and the SAM conferences.
The massive use of air gaps in tooling, per the Evistoe (R) concept, can confine the heat contributed by the cast alloy in a small volume. The resulting high die wall temperatures are turned to account to cast parts having ultra-thin walls, of the order of one millimetre thick. Effective thermal insulation limits thermal exchanges to slow the cooling of a cast alloy. The property that best characterizes this effectiveness is the reciprocal of thermal conductivity, thermal resistance. Air was chosen as the insulating material because of its many advantages: very favourable thermal conductivity, limited application cost, and zero purchase cost. Evistoe (R), an innovative tooling design, has been used to produce plates 1 mm thick measuring 130 by 200 mm and automobile seat backs 1.2 mm thick measuring 390 by 576 mm. The mechanical properties of the castings so produced complied with standard EN 1706 of May 2010 for aluminium alloy castings. A patent application was filed for the Evisto (R) concept in August 2010.
Fracture toughness evaluation of brittle or ductile materials by indentation testing. Micro and nanoindentation tests are widely used to evaluate the fracture toughness of brittle materials. The methods are principally based on the radial cracks length as a function of indentation load. More recently methods were developed in relation with the pop-in observed on the loading portion of the load-displacement curve in instrumented indentation, measurement of the crack opening displacement or chipping induced by indentation near the edge of the material. For ductile materials a new indentation technique was recently introduced for estimating the fracture toughness, although no crack is observed. The critical indentation energy is related to the decreases of Young's modulus measured by indentation and a model based on continuum damage mechanic. In this paper, we propose a retrospective of these different methods using principally sharp indenters. All these methods are attractive because of their simplicity and ease of implementation. However, the uncertainties obtained for the measurement of toughness can be significant and even reach 50%.
The aim of this work is to study the possibility of using zinc phosphating treatment to protect reinforcement steel against pitting corrosion in the concrete. For this investigation, steel samples were subjected to zinc crystalline phosphatation in a classical phosphate bath modified by adding Ni2+ ions. After that we evaluated their corrosion behavior in simulated concrete pore solution by various electrochemical techniques. The obtained results show that the phosphatation treatment improves significantly the corrosion resistance of the steel rebar. In fact, the treated samples, comparatively to those untreated, present nobler values of corrosion and pitting potentials and lower corrosion current densities. The impedance measurements confirm this tendency; the obtained spectra show a significant increase in the charge transfer resistance parallel to a decrease in the capacity of the electrochemical double layer of treated samples. In fact, the coating acts as a physical barrier against the diffusion of chloride ions. In addition, during the dissolution of the phosphate layer in the strongly alkaline simulated solution, the released PO43- ions participate in the reaction of formation of a passivating film playing the role of a chemical barrier against the pitting corrosion initiation.
At the end of 2008 and in response to the economic crisis, the EU launched a Recovery Plan supported by technology initiatives, one of them being the European Green Car Initiative (EGCI) to help the car industry design next-generation passenger vehicles, which address fuel efficiency and carbon footprint issues at the level of the challenges of the 21st century. The European steel sector, which supplies material to the European car industry, which builds 1/3 of all passenger cars in the world, has launched an extensive, bold and imaginative series of projects to address lightweight design, cost, safety, sustainability, availability, recycling, electric applications and Life Cycle Assessment (LCA), which are the main technical topics, as steel retains an essential role in the design of these future green vehicles. Highlights of these are presented here, such as the development of new steel grades, either new advanced high-strength steels or low-loss steels for electric cores, the co-design of steel solutions with OEMs and the importance of LCA in vehicle conception.
est décédé le 17 décembre 2012 à l'âge de 91 ans.Il avait le regard vif, de nombreux talents et de riches moyens d'expression.Jacques Leclerc fut chargé de la Direction Métallurgique d'Usinor et il laisse de nombreux amis métallurgistes « orphelins » d'un modèle intellectuel et professionnel.Il fut un témoin et un acteur de décisions très importantes pour la Sidérurgie Française entre la fin 1945 et le début des années 80. Ingénieur de l'École Polytechnique (X42), il était le fils d'un ingénieur Centralien, chef d'Aciérie à Neuves-Maisons, puis à Montluçon (Compagnie des Forges de Châtillon-Commentry et Neuves-Maisons).Comme d'autres ingénieurs de sa génération, il n'avait pas pu intégrer son école en 1942 et avait du attendre l'année 1944 pour poursuivre ses études.Il avait mis à profit cette période d'attente pour travailler à Montluçon où son père était alors en fonction.Son père pour lequel il avait beaucoup de considération l'avait ainsi amené à découvrir la Sidérurgie et la recherche (il gardait encore les carnets de son père sur lesquels étaient reportées entre-autres des coupes de divers lingots d'acier).Il était rentré à Denain-Anzin, devenu ensuite Usinor, sous la présidence de René Damien, dont il disait qu'il avait reçu la mission de servir en devenant « son métallurgiste » [1].Au cours de sa carrière qui l'a conduit à exercer cette mission au plus haut niveau, il n'a cessé d'approfondir et de développer avec une grande passion les fonctions et les différents volets de cette mission : études et recherches dans le domaine des procédés et des produits, définition des gammes de fabrication et du contrôle de la qualité, méthodes d'investigation, liaisons avec la clientèle. . .Il a réussi à donner à ces métiers un rayonnement de premier plan et à les rendre attractifs pour tous ceux qui ont eu la chance de travailler avec lui.L'exercice de ce métier qu'il a valorisé et rendu « incontournable » l'a conduit à participer à de nombreuses décisions.
The increasing proportion of renewable resources in electricity mixes, the decentralization of energy supply and the growing use of electric vehicles demands the challenging development of reliable, cost effective and flexible energy storage technologies. One option are electrochemical energy storage systems with high specific power and high specific energy density. One of the most promising electrochemical energy storage systems is the lithium-ion batteries (LIB) which are customized regarding size, weight, specific energy and specific capacity what makes batteries ready for operation under different conditions such as emerging electric power systems, grid support or electric mobility [1]. Even though the lithium-Ion technology for traction batteries is not yet widely applied, experiments and first use experiences show that it is a promising electric energy storage system for electric mobility. However, the environmental impacts of battery production, use and recycling are not well understood. To gain a better understanding about the ecological properties of LIBs material and energy flow analysis (MEFA) is conducted. The MEFA defines the possible sources and consumers of relevant materials, substances, pollutants and energy flows [2,3]. The presented study analyses the consumed materials and energy as well as the emitted substances and waste heat of different LIBs. The main focus of the MEFA is on the production phase and includes active and passive components and material such as metal-salts, electrode materials, other functional metals (e.g. current collectors, casing, etc.), plastics (e.g. separator) and electrolytes [4-7] and on energy consumption as well.
This experimental study presents novel composite materials recently developed for joining copper parts. These agar-based compositions may be shaped by powder injection molding. This ease of implementation opens the possibility to produce brazing preforms with complex shapes. Two examples of uses are presented, the first deals on soldering and the other focuses on the brazing. Joints respectively obtained allow to obtain mechanical strength and metallurgical quality similar to those obtained from conventional materials (SnPb or CuP based) used for joining copper tubes.
Equal channel angular pressing is both a novel and an industrialized process among severe plastic deformation methods to fabricate ultra-fine-grained metals and alloys. Verification of a three-dimensional finite element model which compares various strength coefficients and strain-hardening exponents (virtual materials) defined for the plastic deformation behavior of materials was performed with experimental tests. The virtual process numerically analyzed the effects of the strain behavior and pressing force. The results show that strength coefficient enhancement leads to decreased effective strain value, heterogeneous strain distribution and higher pressing force, and an increment in the strain-hardening exponent results in lower pressing force. However, this parameter does not have an obvious effect on the effective strain magnitude and strain dispersal uniformity. Furthermore, the highest imposed effective strain, the best strain distribution homogeneity and the lowest required punch load were achieved for the deformed material with the lowest strength coefficient and highest strain-hardening exponent.
Ecosystem goods and services (EGSs) are of crucial importance for the economic and social development of human communities. The well-established life cycle assessment (LCA) method is facing a number of challenging improvements to define new Characterization factors (CFs) for life cycle impact assessment (LCIA) of EGSs. Very recently, extensive work conducted under the UNEP/SETAC Life Cycle initiative has been completed with the goal of providing new LCIA methods and spatially differentiated mid-point CFs for land use and land use change impacts on biodiversity and ecosystem services. However, the implemented models do not enable one to assess the actual damage to ecosystem functionality, and thus the relationship among EGSs and related areas of protection (e.g. AoP of "Natural Resources") remains undefined. This paper aims at investigating the potential characterization ability of the Emergy method for LCIA of EGSs. The goal is to use the extensive libraries of Unit Emergy Values (UEVs) of primary services and resources as CFs for LCIA to evaluate the physical contribution of EGSs in supporting life cycle processes. Having its roots in thermodynamics and systems ecology, Emergy can appraise a larger and more diversified (than LCA) number of EGSs through a common physical denominator, i.e. the solar emjoule or seJ, which measures the solar energy embodied in natural products. Emergy thus has a typical Nature-oriented perspective, accounting for the available energy that is used up by the natural cycles, directly and indirectly, to generate biotic and abiotic resources. A library of selected UEVs (more than 100) for biophysical EGS valuation has been framed including values collected from the Emergy literature and formulated on the latest planetary baseline (i.e. 15.2E + 24 seJ/yr). Advantages and limitations for future application of these values toward an LCIA mid-point impact characterization of Emergy are discussed. UEVs may represent mid-point LCIA factors for ecological contribution analysis, enabling one to account for the memory of energy previously required to produce EGSs, which can be used as a proxy to assess the future environmental work necessary to regenerate the used EGSs. However, the added value of Emergy for LCA is still debated, mainly because of the low accuracy and unclear meaning of the UEVs in relation to the availability of resources. Therefore, Emergy can be conceived as a suitable physical measure complementary to the economic valuations and current "user-side" tools applied in LCA.
