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Removal efficiency of heavy metal Cu from acid wastewater using egg shell as adsorbent was investigated. The influence of calcination temperature and dosage of egg shell, as well as pH value on the removal efficiency were discussed to obtain the optimum removal condition. The results show that the removal rate of lead would achieve the best result of 99.56% when we use the egg shells calcined at 400°C,2h, and the content of egg shells is 30g/L, pH=3.0.Using eggshells to treat acid chrome-containing wastewater is simple and easy to be operated, which has application prospects for the process and good treatment effect.

Sludge reduction by electrolysis and its subsequent influence on removal rate of COD, NH3-N, PO43- and on the sludge activity in the aeration tank were investigated. In this research, two parallel sequencing batch reactors were used with one set was operated in convention modality and the sludge of the other set was electrolyzed and then fed back to the reactor. The results showed that: sludge electrolyze could reduce the sludge production around 21% and had slight effect on substrate removal efficiency. After the sludge being electrolyzed, removal rate of COD and NH3-N decreased by 1.1% and 6.9%, respectively. PO43- removal rate increased by 6.1%. The number of protozoa, metazoan and protonema decreased and the structure of sludge floc became more compact. Moreover, the activity of microorganism and carbon source metabolism of sludge changed slightly, but the microbial community structure and metabolic function of microorganism had little change.

Castor stalk is one of excellent woody materials.which is the byproduct of the castor oil plant. Itwas usually burnt without use at all when the castor seed were harvest. To use this resource, we studied the castor stalk based panel made with different resin including UF, PF and MDI resin. The results show that the properties of castor stalk based particle panel made with UF and MDI resin by certain techniques can reach the requirement of the standard of China expect the castor stalk based particle board with PF resin which will be studied further more.

Corn cobs are potential feedstock for producing heat, power, fuels, and chemicals. Densification of corn cobs into briquettes/pellets would improve their bulk handling, transportation, and storage properties. The objective of this study was to investigate the densification characteristics and specific energy requirements for the compression of corn cobs under four pressure levels (10, 12, 14, 16MPa) and with two particle size levels (2.41mm, 0.86mm). The compression behavior of ground corn cobs was studied using a hydraulic press briquetteing machine whose cylindrical die diameter was about 30 mm. The corn cobs moisture content and preheat temperature before compaction was 10% (w.b.) and 75 °C, respectively. The cylindrical die temperature was maintained at 90 ± 5 °C. It was found that the briquette density ranged from 809 to 1043 kg m-3; while the total specific energy requirement to compress and extrude briquette ranged from 17 to 26 MJ t-1, with an increase in pressure. Particle size had also a significant effect on briquette density and specific energy requirement. The finer corn cob grinds (0.86mm) resulted in higher density and lower specific energy requirement than the coarser corn cob grinds (2.41mm). New statistical models were developed to describe the total specific energy consumption of ground corn cobs during densification using a multiple linear regression analysis.

A graphene oxide/polyaniline composite was synthesized by an in situ polymerization process. This product was simply prepared in an ethylene glycol medium, using ammonium persulfate as oxidant in ice bath. The composite was characterized by field emission scanning electron microscopy, transmission electron microscopy, X-Ray photoelectron spectroscopy, Raman spectroscopy and electrochemical test. The composite material showed a good electrochemical performance.

SDBS modified graphene was prepared by electrochemical method using Sodium dodecylbenzenesulfonate (SDBS) as electrolyte and graphite rod as electrode. The anode graphite rod was corroded and deposited at the bottom of the electrolyte solution. The obtained graphene was characterized by Atomic force microscopy (AFM), Raman and Fourier transform infrared spectra (FT-IR). AFM images indicated that most of the layers had the thickness of less than 2 nm, suggesting the fromation of single layer of graphene. The resulting graphene showed very good dispersion stability both in water and in organic solvents (ethanol, acetone).

The solvent-based exfoliation of graphite, including into graphene and/or graphene-like platelets, is an important challenge. Here, we report a “direct” Friedel-Crafts acylation reaction between graphite and 4-ethylbenzoic acid (EBA) to afford edge-functionalized graphite (EFG). Unlike, for example, graphite oxide (GO), the functionalization is at the edges of the graphite and thus, the basal plane of individual layers in EFG is not functionalized. The EFG can be easily dispersed and exfoliated in common organic solvents to concentrations as high as 0.8 mg/mL. Large-are uniform films can be produced by solution-casting such dispersions on substrates and conductivities as high as 125 S/cm can be obtained by subsequent heat treatment at 900 °C under argon atmosphere. Hence, a few layers graphene obtained from annealing under argon atmosphere show the potential to replace Indium tin oxide (ITO).

In this work, we synthesized graphene nanosheets via a soft chemistry synthetic route involving pre-exfoliation treatment, strong oxidation, and post thermal exfoliation. X-ray diffraction (XRD), Raman spectroscopy, atomic force microscopy (AFM), and transmission electron microscopy (TEM) confirmed the ordered graphite crystal structure and morphology of graphene nanosheets. N2 adsorption was used to determine the specific surface area of graphene nanosheets. As a result, pre-treatment of the graphite with HNO3/H2SO4 mixture produced the exfoliated graphite nanoplates, and the post thermal exfoliation of the graphite oxide nanosheets at low temperature led to produce a large number graphene nanosheets. The specific surface area of obtained graphene nanosheets was 333 m2/g.

The aim is to treat oily sludge from floatation process of oil produced water by deflocculation. Based upon analyzing the granularity distribution and dewater efficiency of the flocs, floc breakage and dewater of oily sludge was carried out. The results indicated that the coagulant skeleton builder in sludge could be broken by changing the coalescent state, and deflocculation could disrupt skeleton of the floc and release interstitial water in sludge. The highest dewatering efficiency is about 81.2% at the pH of 4.5 by gravity sedimentation. The sludge had a broader range of granularity distribution and a smaller volume-average diameter. Moreover, the median diameter d (0.5) of the treated sludge was 36.0 μm, which was smaller than 73.1 μm of raw sample. Meanwhile, capillary suction time (CST) significantly decreased with pH adjustment. A wastewater removal efficiency of 90.99% for the treated sludge by pressure filtration could be achieved. The method would be a potential technique to be applied to other kinds of floatation sludge.

This study presents the experimental results of using admixture of used engine oil and kerosene as an alternative fuel in foundry shops. In this experiment, several proportions of used engine oil (well filtered) and kerosene were measured to make 1000ml per mixture using a calibrated beaker. Each mixture was fired in a furnacensuring atomization, ignition and combustion in a timed set up. Results of the experiment showed that admixtures of 100%, 95% and 90% volume of used engine oil gave low pour point hence were incombustible. 85%, 80% and 75% volume of used engine oil admixtures gave carburized flame. While 55% and below of used engine oil volume of admixtures gave oxygenated flame. 57% - 70% volume of used engine oil admixtures produced neutral flame which is ideal for melting. Of the latter proportions, 70% of used engine oil admixture had the highest heat content 70,780 kj/kg and the lowest cost. Hence this admixture is recommended as an effective admixture for fuel substitution in the foundry shop.

A moisture-measuring device for the determination of percentage moisture content of cassava particulate on dry basis during drying process was developed used to investigate the effect of pressure on the resistance of the cassava particulate sample. A thermo-gravimetric sample analysis was used for the calibration of the moisture measuring device. The device had four electrode cups, two of which were used as dummies to give a ½ Wheatstone bridge circuit used to measure the resistance. The resistance of the cassava samples increases with decrease in the %moisture content and decreases with increase in pressure.

The papers aim is to detail temper bead realization, as a possible solution to the removal of heat treatments. Applying temper beads could be a solution for repair, in case surface heat treatments are required, provided they are correctly applied. The paper presents the main ways of applying temper beads, presenting in the same time what the outcomes could be in case of not respecting the prescribed work sequence.

The objective of the paper is to present the newest results of our complex research work. In order to determination and comparison of the fatigue resistance, fatigue crack growth tests were performed on different grades of S690QL quenched and tempered, and S960TM thermomechanically rolled high strength steels.15 mmand30 mmthick base materials were used for our investigations. Welded joints were made from these base materials, using gas metal arc welding with matching, overmatching, and undermatching filler metals. In the paper, the performance of the welding experiments will be presented, especially with the difficulties of the filler material selection; along with the results of the fatigue crack growth examinations executed on the base materials and its welded joints. Statistical aspects were applied both for the presenting of the possible locations of the cracks in the base materials and the welded joints and for the processing of the measured data. Furthermore, the results will be compared with each other, and the possibility of derivation of fatigue crack propagation limit curves will be referred.

This paper is concerned with the selected aspects, which are discovered during a design stage of cable and membrane structures, known as “form-finding” process. The aim of this paper is the understanding of the basic principles of the form-finding process and their explanation of the very simple examples. The use of the finding a shape of a tension membrane that is in static equilibrium as an analogy with the search condition of minimal surfaces is explained. The basic principles are demonstrated on simple 2D example, in which the finding a stable minimal surface passes in the finding a stable minimal length.

In this paper, an innovative approach for contact zone analysis of skive hobbing is presented. This process is characterised by varying tool engagements and very small chip thicknesses. The paper describes the process-modelling and the analysis of the workpiece-tool contact. For efficient modelling, a novel dexel-based method for the description of a gear segment with discretized stock allowance is presented. Characteristic for the method is an analytical description of the target workpiece contour which allows to describe points of the surface by Cartesian coordinates on the winding off. On this workpiece contour, dexel are modelled in surface-orthogonal direction. The initial lengths of these dexel describe the stock allowance. By cutting these dexel with a tool, a time-and position-dependent prediction of material removal values, like width of undeformed chip, undeformed chip thickness or cutting directions can be obtained. Selected results are presented and interpreted.

Nuclear experimental instrumentation frequently includes the usage of thin-walled (metallic sheathed) thermocouples passing through the boundaries of pressure vessels. This is accomplished by sealing the thermocouples by brazing through special design fittings (passages) which are later sealed / welded to the body of the vessel.Two are the challenges to face : (a) the manufacture of the instrumented passage (b) its mandatory qualification, according to relevant standards. Even the brazing qualification standards are more flexible than for welding, the peculiar situation of nuclear instrumentation still needs special consideration and it is not properly covered by the regular standards.The paper describes the experience of the authors in manufacture of the instrumented passages with steel or Inconel sheathed thermocouples, along with some other known projects, in conjunction with applicability of relevant standards: ASME code, AWS standards, national standards. Since it is about pressure vessels, ASME prescriptions are mandatory in Romania; other standards may serve as valuable sources for the “engineering judgment” allowed and recommended by ASME code.The main problem in such specialty brazing qualification is that for some combinations of base metals and filler (imposed by application), one cannot avoid the significant fragilization due to a tremendous increase of hardness in the brazing area. Base material erosion is added and the effect is catastrophic : sectioning the thermocouples at the slightest movement. For example, brazing Inconel thin-walled tubes with BNi-7 is very hard to control – experimental data and images are included in the paper to illustrate this.Therefore, special means must be applied both in fabrication and in qualification, in order to ensure the product is functional and safe, even being fragile. This approach can be found in French design of irradiation devices, being also considered in the French code for design and construction of experimental reactors and irradiation devices. Being known that French experience in this field is vast, their approach makes us confident that our brazing technique is not wrong but the problem is to be solved through ‘smart’ design and specific procedures. Consequently a tentative set of domestic rules for work and qualification is proposed for discussion and further improvement.

In the paper there are presented experimental results concerning mechanical characteristics of friction-welded joints in comparison with electron beam welded joints, made by 20VNiMoCr120 heat-resistant steel, which are part of some elements working at high pressure and temperature. The paper represents a study which suggests non-conventional welding and heat-treatment procedures for water and steam-supply pipes, large cylindrical recipients with high values of wall thickness, boiler pipes, steam turbines which compose thermo-energetic installations, in order to prevent failure appearance. The actual level of development in all activity fields proves the fact that on top of the performance and modernism, technological products and processes must assure a high reliability. All the results and experimental researches are obtained by the first author in her PhD Thesis.

In this paper there are presented results of research carried out for establishing the most favourable scenario of curing of the Polymer-Cement Concrete (PCC). The general recommendations for PCC point to the need of alternating conditions of curing of PCC. Polymer-cement concrete should be first cured in the wet conditions for effective hydration of Portland cement and then in air-dry conditions for polymer setting. According to the literature, the often accepted curing regime of PCC covers 5 days of wet curing and then the air-dry curing until the time of testing. According to the European Standards, the wet period should last 3 days. However, the authors` experiences show that the aforementioned scenarios is not the optimum one. The studies presented in this paper are the part of the larger research program, which – according to the authors` intention – should lead to the establishing of the optimum curing regime for PCC. The tests were carried out using two types of polymer modifiers: two-component epoxy resin and water dispersion of polyacrylates, introduced into the cement concrete mix. The following properties were accepted as the criteria of evaluation of PCC curing effectiveness: compressive strength, tensile splitting strength, surface tensile strength (by pull-off method), wear resistance, water penetration under pressure. These properties were evaluated after 28 days of curing according to the various regimes. The tests showed that the extension of the wet curing period beyond 5 days was favourable for the technical properties of PCC. The establishing of the optimum time of wet curing, however, needs further research. Also, some conclusions were formulated about the usefulness of the various properties as the criteria of PCC curing efficiency evaluation.

The paper presents results of the researches conducted upon the use of the arc-air gouging process with coated electrodes, in comparison with the plasma gouging process, in case of the welded structures. The paper aims at submitting the arc-air gouging technologies with electrodes and the plasma gouging technologies. The research consists in gouging a structural steel, of the quality S275JR and in comparing the surfaces obtained by the enumerated processes. The obtained samples will be analyzed in terms of microstructure, macrostructure, hardness of the thermally influenced area, hardness of the gouged area.The gouging process is based on melting the raw material, with an electric arc achieved between an electrode and the raw material; and on removing the melt material with a compressed-air jet, in the case of the arc-air gouging and plasma gouging. The gouging with coated electrode is different, given that it requires special electrodes, with thick flux cover, in order to generate an electric arc and a strong gas flux. During the gouging process, the raw material will be oxidized; yet, this does not influence the process. The gouging process can be either manual or automated. In this paper, the manual variant will be submitted, in the case of the arc-air gouging technology and the gouging with coated electrodes; in the case of the plasma gouging, both variants will be submitted.

The paper is focused on the use of advanced composite materials in the real application areas of buildings exposed to extreme environmental stress. The paper describe properties of composite rebar, especially with regards to long-term resistance to chemical and corrosion attack, minimization of heat transfer or resistance in construction with reduced concrete cover. The paper also presents behavior of composite rebar and concrete samples with composite reinforcement during loading and fire tests.

This paper refers to behaviour and capacity of axially loaded columns strengthened under load using welded steel plates. This method of strengthening is fast, simple and widely used but no universal and reliable analytical solution has been presented yet. In the paper, focus is put on flexural buckling. The approach using cross-section properties of strengthened member and the modified buckling reduction factor was used to calculate the ultimate resistance. In buckling theory, the resistance of column subjected to compression load is reached when the most stressed fibres start to yield. However, some researchers allow certain amount of yielding for base material of columns strengthened under load. In the paper, the new modified buckling reduction factor based on Eurocodes is derived. Two types of column strengthening under various preload magnitudes are investigated using finite element study in ANSYS code and transient analysis type. Birth and death of elements is used to simulate strengthening welded plates. The results are compared with analytical solutions.

The thermal cycles simulator of welding is a complex equipment that reproduces in a specimen thermal cycles of the type caused in the HAZ by welding processes.In this paper, it is presented a comparison between the results obtained by welded joints and thermal cycle simulator specimens, from the material P355NH of 22 mm thickness for pressure vessels. Two types of thermal cycle simulator specimens were used: one specimen without post-simulation heat treatment and one specimen with post-simulation heat treatment.For the welded specimens Mn3Ni1CrMo filler material was used.This paper offers information about the impact energy of specific areas of the welded joints, both for butt welding and thermal cycle simulator specimens.A good correlation was observed between the results of thermal cycle simulation with post-simulation heat treatment and the results obtained by welding.

The present paper shows the experimental results obtained on two complex alloys Co-Cr-W-C-Fe-Ni-Si-Mn-Mo and Ni-Cr-Fe-B-Si-C-Co alloys deposited on copper support by welding (TIG). Well - known for their excellent abrasive wear, corrosion and high temperature erosion resistance, these materials were chosen as protective solutions for some highly mechanically and thermally stressed devices, namely the blast tuyeres of blast furnaces. A testing method which simulates as near as possible the real working conditions is the quick thermal shock, consisting in heating at the chosen testing temperature followed by cooling in cool air spray, for 25 cycles. Testing parameters were set according to the blast tuyere device working conditions. In this paper, the coatings microstructure’s comparative changes consequently to quick thermal shock were monitoring, because this affect the device lifetime and mechanical characteristics. The untested samples as well as on quick thermal shocked ones was investigated using X-ray diffraction, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS).

Development of new steels with higher creep resistance must be based on detailed knowledge of strengthening and degradation processes, structural stability at high temperature exposure and their welding. This paper is concerned with the real weld joint hardness and microstructure of progressive low alloy creep resistance T24 steel. These steel is widely used in many power-plant constructions all over the Europe. Welding the T24 steels components is one of the most important technological procedures. The aim of the performed investigation is to evaluate the hardness and microstructure in the heat affected zone (HAZ) and the weld metal. Results of the secondary hardening in the real weld joints after low temperature post weld heat treatment (460°C/48h) and without post weld heat treatment at service temperature are described in this paper. Obtained results are compared to the hardness values of the weld joint post weld heat treated at recommended temperature (740°C). The microstructure of the real weld joints was analysed by transmission electron microscopy (TEM) in order to identify minority phases - MX nanoparticles and/or coarse (M23C6) particles. Secondary hardening of the not heat treated and low temperature heat treated T24 weld joint was proved.

The computing industry is one of the fastest growing industries and it is caused by the rapid progression of computer hardware and software technological developments. The high-capacity storage systems become the important element of the network architectures. The network architectures of high-capacity storage systems can be developed by using various, different techniques. The present paper aims to give a review about the storage systems architecture, systematize the various types of connection, and present the significance of virtualization. Based on industry specific literature and on own research, the present paper sets up a clear systematization of these techniques by providing a brief summary of their essence, while also providing examples of their application in different network storages. The present article also provides an insight into the topic of the different connecting types of network systems, while highlighting the importance of virtualization and application of the iSCSI technology. After the explanation of the challenge of redundancies in storage systems, the author outlines the importance of using RAID (Redundant Array of Independent Disks) technology for handling the issue of redundancy

This paper represents a two degree of freedom (DoF) robot arm as a plotter system. A pencil tool is used as the end effector of the robotic arm and experimented in drawing alphabets, for example ‘IIUM’. The control mechanism of the prototype is designed using Arduino controller. A user interface is also designed to send necessary commands to the hardware application board using serial communication cable. Through the experimentation, the movement of each joint of the robotic arm is presented in this paper. The result proves the feasibility of the system which could be improved in future research in drawing complex images.

Graphene is a two-dimensional material consisting of single atomic layers of graphite. Its quality is markedly different from conventional graphite and semiconductor material. In this paper, electrical conductivity and Hall Effect of the graphene were measured at room temperature by Var der Pauw method. An ohmic contact of the sample and the electrodes was constructed and tested before the measurement of Hall Effect. With the help of the Var der Pauw method, the Hall voltages of the samples were measured under the static magnetic field and different input currents. Sequentially, a series of Hall parameters of graphene were obtained. The results shown that the Hall coefficient RH is 7.00*10-7 m3/C; the carrier concentration n is 10.52*1024 m-3 that is fifteen orders of magnitude bigger than silicon; the Hall element production sensitivity KH is 6.87*102 m2/C and the carrier mobility was 1,882.54 cm2·V-1·s-1 which is much bigger than silicon. The measurement results in this paper can provide some reference for graphene’s research and application in related areas.

This paper presents in detail the laser welding of a new mechatronic component belonging to the pressure sensors made ​​by aluminum alloy AW2007. Due to very high reflectivity of aluminum alloys, fast oxidation, the absorption of gases from the surrounding medium, special difficulties arise at laser beam welding and most situations require appropriate surface pretreatment. Given these issues, the paper present an experimental study on the influence of welding parameters on the seam quality for the aluminum alloy AW2007. In addition of the study regarding the influence of welding parameters, such as, laser power, welding speed, we conducted an analysis on the influence of the initial temperature of the material on the quality of the weld. Besides these aspects the paper presents a constructive solution for a device used to optimize the laser welding process of the sensor.

As organic transistors are preparing to make improvements towards flexible and low cost electronics applications, the analytical models and simulation methods were demanded to predict the optimized performance and circuit design. In this paper, we investigated the analytical model of an organic transistor device and simulate the output and transfer characteristics of the device using MATLAB tools for different channel length (L) of the organic transistor. In the simulation, the Pool-Frenkel mobility model was used to represent the conductive channel of organic transistor. The different channel length has been simulated with the value of 50 μm, 10 μm and 5 μm. This research paper analyses the performance of organic thin film transistor (TFT) for top contact bottom gate device. From the simulation, drain current of organic transistor was increased as the channel length decreased. Other extraction value such sub-threshold and current on/off ratio is 0.41 V and 21.1 respectively. Thus, the simulation provides significant extraction of information about the behaviour of the organic thin film transistor.

Nanotechnology has become a driving power in most of the branches of industry recently and construction industry is not an exception. Therefore, this paper deals with the topical problem of using nanoparticles in concrete. Carbon nanotubes (CNTs) with exceptional physico-mechanical properties were used in the experimental part of the paper. Their potential for enhancing characteristics of common concrete is promising. A frequent problem of application of carbon nanotubes is their agglomeration, which is caused by high surface tension, Van der Waals force and high ratio of sides. This fact limits possibilities of application of CNTs and it is the main reason of rare use of the promising potential of CNTs. Formed agglomerations can be dispersed by adding energy from outside and if suitable surface active agent in the solution of CNTs and water is added, their re-agglomeration can be prevented. Experimental part of the paper focuses on possibilities of dispersing CNTs by means of ultrasonic homogenizer Bandelin Sonopulse HD 3200 and suitable surface-active substance. Tests specimens were prepared from a suspension of water and CNTs with two different proportions and development of physico-mechanical properties in time was observed. Results confirmed the trends described in foreign literature sources and gave valuable impulses for further attempts to use nanotechnology in concrete technology.

Surface acoustic wave can be generated at the free surface of an elastic solid. Interdigital transducers (IDTs) are fabricated on the piezoelectric substrate surface that will act as electrical input and output port. When appropriate AC voltage stimulus is applied to the input transducer, surface acoustic wave will be produced. The output or receiving port will detect the incident surface acoustic wave and convert it back to a suitably filtered electrical once. For this property, surface acoustic based devices were initially developed for the telecommunication purpose such as signal filters and resonators. SAW based devices have been modified to be sensors later on from for gas detections and have been moving towards biological detections recently for its ultra-sensitivity to surface perturbation. The main component of this device is the IDTs. Recently, there are several methods to produce IDTs; Ultra-Violet (UV), deep UV lithography, Electron beam (e-beam) lithography and X-ray lithography. Although, these methods can produce very fine and accurate electrodes in term of submicron size but the costs are extremely expensive. Thus, this paper will discuss the conventional CMOS method which is much more economical to produce the applicable IDTs for the bacterial pathogens sensing purpose. Shear horizontal surface acoustic wave (SHSAW), one of the SAW based types is used in this paper as it is most suitable for the liquid based application as it has the advantage of acoustic energy is not being radiated into liquid.

For the present situation of spotty mask fabrics in current market, the paper used natural fiber silk as raw materials for the study of anti-fog and haze mask fabrics. The paper design five different programs and any one sample in every program has different weft density or warp and weft yarn fabric specifications. Make total of 15 kinds of trial samples and do a series of testing of fabric performance. Through testing the pore size value, the filtration efficiency, resistance value and other indicators and analyzing the results, do research on filtering properties of the fabrics. The conclusions have certain guiding significance in product development.

It’s generally accepted that the transport of lithium ions in solid polymer electrolytes exists mainly in the amorphous regions, thus the research has focused on reducing the crystallinity to obtain high conductivity at room temperature. However, the point has been challenged: crystalline systems can provide a better ionic conductivity. In this paper, PEO/LiClO4polymer electrolytes with different lithium-oxygen ratios were prepared by melt-blending. The results show that [EO]/ [Li+] = 3 system has higher ionic conductivity, 4.26×10-6S/cm, more than twice as that of [EO]/ [Li+] = 4 system. DSC and XRD results show PEO3:LiClO4crystalline phase present in both systems, the crystallinity of [EO]/ [Li+] = 3 system is higher. It illustrates the generally accepted mechanism is not suitable for these systems, suggesting the high conductivity of [EO]/ [Li+] = 3 system is due to the unique crystal structure of PEO3:LiClO4. Besides, as the crystallinity increases, the tensile strength of [EO]/ [Li+] = 3 system increases greatly, to 1.43 MPa. In addition, because of the high melt temperature of PEO3:LiClO4, the electrolytes will gain excellent heat resistance. In summary, this paper provides a new idea to prepare polymer electrolytes with high ionic conductivity, improved strength and excellent heat resistance in large scale.

Copper alloys with high strength and high conductivity are a serial of materials with excellent comprehensive performance. However, the strength and the conductivity are a pair of conflicting factors. To resolve this contradiction, Cu-1.0Cr-0.12Zr alloy was studied in this paper. With optical microscope, scanning electron microscope, Brinell hardness and the arms bridge, effects of heat treatment on microstructure and properties of such alloys was studied,and we strived to find a heat treatment processing to achieve the best match between the conductivity and the strength of the alloy. This paper focused on the study of conductive properties of the alloy. The main factor infuencing the conductivity of the alloy was the content of the soluting elements. The higher the content,the lower the conductivity, and vice versa. The results showed that the best comprehensive properties were obtained after solid solution at 920°C and then aging at 450°C for 180 min.

Changing "high consumption energy, low temperature heat to the indoor, waste heat to the environment", and turning the HVAC harmoniously into the natural ecological cycle, conform to the trend of the development of ecological architecture. Heat pump technology is a way of HVAC energy saving the most practical. Although low heat and cold source of the city sewage is ideal, but the quality is very unstable, can not meet the operation requirements of heat exchange equipment. This paper analyzes the key problems of the sewage side in sewage source heat pump technology application in the present: hair dirt clog sewage heat exchanger; fouling in heat surface reduces the heat transfer performance, and results in large heat-transfer equipment in the practical application. According to the key problems of sewage side, this paper prevents hair clogged with large tube heat exchanger; reduces the fouling thermal resistance, and enhances heat transfer process using the heat exchanging technology of circulating fluidized bed.

Oblique incidence lasertriangulation was used to detect medium and heavy plate flatness in this paper.The article mainly focused on point laser spot center extraction algorithm. Infielddetection of medium and heavy plate flatness, according to the problem of thepoint laser spot center extraction difficulty in interference condition, andfor enhancing lightness of spot center filed, an extraction algorithm of pointlaser spot center is put forward in this paper which combines threshold methodand square-weighted gray level based on floor board effect and traditionalcentroid method. Under no interference condition, point laser spot centerextraction using traditional centroid method has high accuracy. In the fielddetection with dusts, oil drops, water drops or other interferences,measurement precision has since fallen sharply. On this background, accordingto a kind of point laser spot center with the interference of water drops oroil drops, classification extraction algorithm of point laser spot center wasput forward in this paper. At the first level, the spot and the drop contourwas extracted with Sobel Operators. At the second level, the spot area wasextracted. And then, this spot area center was extracted by a point laser spotcenter extraction algorithm which combines threshold method and square-weightedgray level. And the center we get is point laser spot center. The validationresults show that with the water drop interference, the accuracy with a pointlaser spot center extraction algorithm which combines threshold method andsquare-weighted gray level is obviously improved by 94.17% than the traditionalcentroid method.

The intelligrid-oriented on-line relay settings verification system based on EMS real-time data are discussed, with related software system designed and fulfilled. Firstly, the research background and current situation of on-line relay settings verification system are summarized. Secondly, the on-line relay settings verification system's general principle, hardware and software design are mainly discussed. And this paper shows the designed hardware structure diagram, the software structure diagram. And the flowchart of main procedure is given. Thirdly, the methods of dealing with EMS real-time data of the on-line verification system are discussed in detail. The verifying principles of sensitivity & selectivity of relay protection are given definitely. It is able to simulate two simultaneous faults, faults in network oscillation, and faults during auto-reclosing. It checks reliability & sensitivity of relay settings under these circumstances. Finally, considering substation-area and wide-area relay protections, this paper points out some key problems of on-line relay settings verification system to be resolved, and its application prospect.

This paper presents a method based improved particle swarm optimization optimizing PI control parameters. When the load changes, parallel active power filter, in the traditional PI control strategies, can not well control DC voltage fluctuations leading the deterioration of its dynamic performance. This paper proposes the improved particle swarm algorithm by increasing symbolic function of inertia weight parameter in particle swarm algorithm, and changing position of the random number in the speed update equation. The improved particle swarm algorithm can avoid "premature" or fall into local optimal solution, so it could get a more accurate solution set. Using improved particle swarm algorithm to solve PI controller optimization objective function, to get a more accurate PI control parameters. Simulation and experimental results show that mutations in the case load, the overshooting of an capacitor DC voltage compare with the traditional PI control reduces 5.5%, compared with Particle Swarm Optimization reduces 1.5%. Based on the simulation analyses and experimental results, it has been proved that this method can realize a comprehensive optimization.

The control system of ventilation to engine room which based on Profibus-DP field bus and Siemens S7-300PLC is introduced in this paper. This paper also describes how to construct the control system by applying the Profibus-DP and S7-300 and the development of the supervision and control system using Wincc. The hardware and software design and system program are also presented in this paper. It has some application value.

When the large oil-immersed transformer start with heavy load in cold regions, due to the high viscosity of the oil at low temperatures, the flow of the oil is extremely slow in the early start of heavy load, resulting in a negative heat radiation. At the same time, the winding and the core are rapidly increasing heat in the early start of heavy load. Rapid increase in heat and the lack of heat dissipation caused a series of problems. In this paper, we study the process of heating and cooling when the large oil-immersed transformer start with heavy load in cold region and takes a transformer of 31.5MVA as example to build a three-dimensional model ,the model is based on the actual size of the transformer. We use the finite volume method to calculate three-dimensional temperature field distribution changing with time when the oil-immersed transformer startup with heavy load in - 35 °C,-30 °C and-25 °C three cases. The results show that the viscosity coefficient of transformer oil is very high at low temperatures. In the early start of the transformer, because of the poor fluidity of the oil, the heat cannot be dissipated in time and the transformer local overheating near the winding. Then we analyzes the damage of local overheating for a short period of time in the transformer, especially the damage of the oiled paper's insulation At last ,we analysis of the causes of transformer internal local overheating and give some measures to avoid local overheating when oil-immersed transformer start with heavy load in cold regions.KEYWORDS: oil-immersed transformer, cold regions, start with heavy load, FVM, three-dimensional temperature distribution

Elbow as common components in the gas pipeline fails easily to natural gas carrying solid particle erosion in the process of practical work. From the viewpoint of hydromechanics, the paper analyses the flow field distribution of manifold pressure and gas-solid trajectory by using the Gambit model and Fluent software in view of the right-angle elbow and numerical simulation of the adjacent manifold. The result obtains the situation about the manifold inner wall by the solid particle erosion wear. The simulation results show more intuitively the elbow, the most prone to erosion part in the manifold adjacent area and shape in erosion. Meanwhile, the paper analyses the factors affecting the occurrence and development of erosion.

The paper detailed expounds the intelligent attendance system, the design method,the purpose of the software process and can achieve results. The intelligentattendance system adopts the light emitting diode and photodiode photoelectricsensor circuit, complete student number recognition, by AT89S52 single chipmicrocomputer as the core, memory chip and display circuit constitute the mainpart of the system. The paper presents a smart attendance system hardwarecircuit design and software design flow chart.

the paper adopts measurement method along with questionnaire method to do research about indoor environment of several universities. Related parameter indexes in measurement are temperature, relative humidity, velocity & concentration of carbon dioxide indoors and outdoors. And the paper employs questionnaire method to get the staff’s subject impression on indoor environment. The results show that while implementing its basic function, university gymnasiums has a tendency to neglect the comfort for staff indoors, and also reflects the relevant issues between air quality and ventilation indoors.

The pull-in behavior of carbon nanotubes (CNTs), which is the sudden increase in the deflection of two interacting CNTs, affects the properties of CNT networks significantly, and thus becomes an important subject in applications. In this paper, an energy-based analysis is carried out to predict the pull-in behavior as well as the critical pull-in distance between two interacting CNTs, and the results agree well with the subsequent atomistic simulations. Furthermore, the factors that affect the critical pull-in distance are also investigated. It is found that the length and diameter of CNTs and space angle between CNTs affect the critical pull-in distance significantly: the critical pull-in distance increases almost linearly with the increasing CNT length and decreasing CNT diameter, and the parallel CNTs have a much higher critical pull-in distance than the non-parallel CNTs. Besides, the chirality of CNTs has a little influence, and when the two CNTs are both zigzag and armchair, the critical pull-in distance is higher than the CNTs with other chiralities due to their stronger commensurability effect. The method and results in this paper will provide nanoscale reference for the design and optimization of CNT-based nanomaterials and nanodevices.

The development of China's nuclear power industry is very rapid in recent years, nuclear generator also gets great development. With the increase of generator unit capacity, The service life and reliability of the generator is improved too. Among them, transient thermal generator operation ability is one of the key factors that affects the service life and reliability of generator. This paper mainly carries on to the generator produces in asymmetric operation process of negative sequence current and transient negative sequence component analysis theory, and with a turbo generator as an example, the voltage and current in different running states of the generator and the air gap flux density were compared and analyzed with finite element method. The conclusion of this paper has reference significance to deeply research the future of generator negative sequence component.

Steel silos are commonly constructed by welding together a large number of curved steel panels with lap joints.Where the lap runs horizontally around the silo circumference, the lap connection causes a local eccentricity in the line of vertical thrust in the shell wall. This eccentricity induces high local bending stresses, which are detrimental to the stability of the structure. This paper chooses a flat-bottom squat steel silo as the research object to analyze the stability of lap-jointed steel silo by comparing with a butt-jointed steel silo. By stressing loads calculated according to Chinese code for design of grain steel silos, considering two load cases including axial compression only and combined axial compression and internal pressure, this paper performs numerical analysises including linear buckling analysis, geometric nonlinear elastic analysis and geometrically and materially nonlinear analysis to study the effects of material nonlinearity and lap joint on stability.

Failure analysis (FA) is a critical element in the development of engineering processes and products. FA of components is the process of identifying failure mode/mechanism and finding out the causes of failure that relies on using of different testing techniques and analysis methods. It provides information necessary for technology advancement and for corrective action to improve quality and reliability. IC’s for military and space applications have extremely stringent reliability requirements. In this paper, the role of FA was discussed. And common and new techniques and tools were reviewed. Then the failure analysis of NPN transistors G3GGA was completed. Conclusions and recommendations for the analysis of failure sample and additional sample within the same batch are drawn from the discussions. This paper might serve as a reference to laboratories when encountering such problems.

Both the cost-effective operation of power systems and reliable operation are inextricably linked with the transformer life assessment. This paper analyzes the composition of the transformer life, life assessment factors and existing assessment methods. Based on factors of the current life assessment and problems of assessment methods, the paper analyzed the importance significance of uncertainty in the transformer life assessment and proposed the transformer remaining life assessment model, and methods based the random fuzzy theory. Assessment results can provide the basis for the transformer maintenance and help safe and economic operation of power systems.

Concrete mechanical properties under dynamic load such as blast and impact are very complex. Shock wave propagation law and damage effect in the concrete were studied numerically in the paper by using TNT explosive ignition and growth model, concrete dynamic damage model, and SPH method. And shock wave properties of different mass explosives in the concrete were analyzed with the similarity theory. The result shows that TNT shock wave propagation law meets the internal-blast similarity law. Peak pressure, positive pressure impulse, maximum velocity and maximum acceleration in the concrete decrease with the increase of scaled distance. And time needed for reaching peak pressure increases linearly with the increase of scaled distance. A theoretical basis of structure and protection design for constructions is achieved in the paper.

In the paper, according to crushing and attrition of material on mixer blade, the mechanical model of material on blade is established. According to nonlinear vibration and the basic theory of rotor dynamics, Mechanical model of vibration system and differential equations of motion are established. This paper has adopted the arithmetic of fourth-order Runge-Kutta, analyzing wave forms graph, chart of axis track, phase plane plot of system movement. Analysis results show that mixer system appears chaotic motion under some certain design parameters. This state of motion on mixers can better destroy cement coagulation group, increasing the number of effective collision of concrete particle, which can effectively improve the microscopic homogeneity of concrete and improve efficiency of concrete mixing.