scholarly journals Recyclability Process of Gypsum Reinforced with Hemp Fabrics: Impact and Flexural Behaviour

2021 ◽  
Author(s):  
Luca Boccarusso ◽  
Davide Mocerino ◽  
Massimo Durante ◽  
Fabio Iucolano ◽  
Fabrizio Memola Capece Minutolo ◽  
...  
Keyword(s):  
Mechanical Response ◽  
Low Cost ◽  
Energy Levels ◽  
Recycling Process ◽  
Three Point Bending ◽  
Recycled Gypsum ◽  
Building Walls ◽  
Flexural Resistance ◽  
Grinding Time ◽  
Industrial Company

Gypsum is an ancient material, still widely used and suitable for many applications in the constructions due to its low cost, availability, lightweight, good thermal and sound isolating behaviour, fire resistance and low energy consumption. One of the most established application is its use as building walls and as pointed out in authors previous research works, it can be very useful and interesting to reinforce the gypsum with vegetable fibres like hemp. This aspect is in line with the current world situation where every industrial company needs to decrease the materials waste, increase recyclability and use more eco-friendly materials. Therefore, this work aims at designing, manufacturing, and testing of both commercial and recycled gypsum specimens reinforced with hemp fabrics, in order to improve impact and flexural resistance of traditional gypsum boards. The recycling process was carefully studied to detect the best grinding time, temperature and time of the heat treatment required to allow the reutilization of gypsum powders. Three point bending and impact tests at different energy levels were carried out in order to understand how the presence of the hemp fabrics within the gypsum matrix and how the recycling process affect the mechanical response of reinforced gypsum.

Mechanical Response of Porous Copper Manufactured by Lost Carbonate Sintering Process

2007 ◽  
Vol 539-543 ◽  
pp. 1863-1867 ◽  
Author(s):  
X.F. Tao ◽  
Li Ping Zhang ◽  
Y.Y. Zhao
Keyword(s):  
Particle Size ◽  
Flexural Strength ◽  
Relative Density ◽  
Mechanical Response ◽  
Compaction Pressure ◽  
Absorption Capacity ◽  
Energy Absorption Capacity ◽  
Three Point Bending ◽  
Porous Copper ◽  
The Impact

This paper investigated the mechanical response of porous copper manufactured by LCS under three-point bending and Charpy impact conditions. The effects of the compaction pressure and K2CO3 particle size used in producing the porous copper samples and the relative density of the samples were studied. The apparent modulus, flexural strength and energy absorption capacity in three-point bending tests increased exponentially with increasing relative density. The impact strength was not markedly sensitive to relative density and had values within 7 – 9 kJ/m2 for the relative densities in the range 0.17 – 0.31. The amount of energy absorbed by a porous copper sample in the impact test was much higher than that absorbed in the three-point bending test, impling that loading strain rate had a significant effect on the deformation mechanisms. Increasing compaction pressure and increasing K2CO3 particle size resulted in significant increases in the flexural strength and the bending energy absorption capacity, both owing to the reduced sintering defects.

Porphyrin doping of dichloride-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex for electroluminescence

2013 ◽  
Vol 17 (05) ◽  
pp. 351-358 ◽  
Author(s):  
Mohammad Janghouri ◽  
Ezeddin Mohajerani ◽  
Mostafa M. Amini ◽  
Naser Safari
Keyword(s):  
Molecular Orbital ◽  
Light Emitting Diode ◽  
Low Cost ◽  
Energy Levels ◽  
Orbital Energy ◽  
Homogeneous Layer ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Fundamental Structure ◽  
Organic Light

A method for obtaining red emission from an organic-light emitting diode has been developed by dissolving red and yellow dyes in a common solvent and thermally evaporating the mixture in a single furnace. Dichlorido-bis(5,7-dichloroquinolin-8-olato)tin(IV) complex ( Q2SnCl2 , Q = 5,7-dichloro-8-hydroxyquinoline) has been synthesized for using as a fluorescent material in organic light-emitting diodes (OLEDs). The electronic states HOMO (Highest Occupied Molecular Orbital)/LUMO (Lowest Occupied Molecular Orbital) energy levels explored by means of cyclic voltammetry measurements. A device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/ Q2SnCl2/Al (180nm) was fabricated and its electroluminescence performance at various thicknesses of light emitting layer (LEL) of Q2SnCl2 is reported. By following this step, an optimal thickness for the doping effect was also identified and explained. Finally a device with fundamental structure of ITO/PEDOT:PSS (55nm)/PVK (90nm)/meso-tetraphenylporphyrin (TPP): Q2SnCl2 (75nm)/ Al (180nm) was fabricated and its electroluminescence performance at various concentrations of dye has been investigated. It is shown that this new method is promising candidate for fabrication of low cost OLEDs at more homogeneous layer.

scholarly journals Photocatalytic Overall Water Splitting by SrTiO3 with Surface Oxygen Vacancies

Nanomaterials ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 2572
Author(s):  
Yanfei Fan ◽  
Yan Liu ◽  
Hongyu Cui ◽  
Wen Wang ◽  
Qiaoyan Shang ◽  
...  
Keyword(s):  
Visible Light ◽  
Water Splitting ◽  
Oxygen Vacancies ◽  
Low Cost ◽  
Energy Levels ◽  
Light Response ◽  
Hydrogen Energy ◽  
Surface Oxygen ◽  
Carbon Reduction ◽  
Overall Water Splitting

Strontium Titanate has a typical perovskite structure with advantages of low cost and photochemical stability. However, the wide bandgap and rapid recombination of electrons and holes limited its application in photocatalysis. In this work, a SrTiO3 material with surface oxygen vacancies was synthesized via carbon reduction under a high temperature. It was successfully applied for photocatalytic overall water splitting to produce clean hydrogen energy under visible light irradiation without any sacrificial reagent for the first time. The photocatalytic overall water splitting ability of the as-prepared SrTiO3-C950 is attributed to the surface oxygen vacancies that can make suitable energy levels for visible light response, improving the separation and transfer efficiency of photogenerated carriers.

scholarly journals Experimental analysis of chemical demulsification of cutting oil

2018 ◽  
pp. 28-37
Author(s):  
Piotr Pacholski ◽  
Jerzy Sęk
Keyword(s):  
Aluminum Sulfate ◽  
Low Cost ◽  
Metalworking Fluids ◽  
Optimal Dosage ◽  
Recycling Process ◽  
Lubricant Oil ◽  
Metalworking Fluid ◽  
Oil In Water ◽  
Oil Water

The wastewater produced by the metal industry is often present in the form of oil-in-water (O/W) or water-in- oil (W/O) emulsions. These fluids contain a certain amount of valuable oil that can be recovered in the recycling process. Therefore, the development of novel, efficient, and low cost processes for the treatment of metalworking fluid is necessary. Demulsification to separate oil/water mixtures is a very interesting option because it allows the recovery and reuse of the lubricant oil and effects in cleaner, easily treatablemwastewater.Chemical destabilization is the most common way of demulsification of metalworking fluids. As an example, inorganic salts can be used as demulsifiers. In the presented work the efficiency of treatment of cutting emulsions with chemical demulsification with usage of aluminum sulfate (IV) is described. The emulsion was prepared with Emulgol-ES12 self-emulsyfing oil delivered by Orlen S.A. In the research the feasibility of the demulsifier was checked.The novel in this paper is determination of the optimal dosage of emulsifier using the TurbiscanLab® apparatus. It is relatively quick and precise method that can be applied in the industry.

Designing Composites for Graceful Failure

2020 ◽  
Author(s):  
Amany Micheal ◽  
Yehia Bahei-El-Din ◽  
Mahmoud E. Abd El-Latief
Keyword(s):  
Mechanical Properties ◽  
Energy Dissipation ◽  
Composite Laminates ◽  
Ultimate Load ◽  
Low Cost ◽  
Cost Effective ◽  
Carbon Composite ◽  
Three Point Bending ◽  
Glass Carbon ◽  
Effective Product

Abstract When inevitable, failure in composite laminates is preferred to occur gracefully to avoid loss of property and possibly life. While the inherent inhomogeneity leads to slow dissipation of damage-related energy, overall failure is fiber-dominated and occurs in a rather brittle manner. Multidirectional plies usually give a more ductile response. Additionally, stiffness and strength as well as cost are important factors to consider in designing composite laminates. It is hence desirable to optimize for high mechanical properties and low cost while keeping graceful failure. Designing composite laminates with hybrid systems and layups, which permit gradual damage energy dissipation, are two ways proposed in this work to optimize for mechanical properties while avoiding catastrophic failure. In the hybrid system design, combining the less expensive glass reinforced plies with carbon reinforced plies offers a cost-effective product, marginal mechanical properties change and ductile profile upon failure. Hybrid glass/carbon composite laminates subjected to three-point bending showed strain to failure which is double that measured for carbon composite specimens, without affecting the ultimate load. Energy dissipation mechanisms were also created by building laminates which were intentionally made discontinuous by introducing cuts in the fibers of the interior plies. This created a longer path for damage before cutting through the next ply resulting in double failure strain with marginal reduction in load. The effect of fiber discontinuity in terms of spacing and distribution are among the factors considered.

scholarly journals Influence of Thermomechanical Treatment on the Mechanical Behavior of Protaper Gold versus Protaper Universal (A Finite Element Study)

2019 ◽  
Vol 7 (13) ◽  
pp. 2157-2161 ◽  
Author(s):  
Manar Galal ◽  
Amira Galal Ismail ◽  
Nada Omar ◽  
Mohamed Zaazou ◽  
Mohamed Abdallah Nassar
Keyword(s):  
Finite Element ◽  
Thermomechanical Treatment ◽  
Mechanical Response ◽  
3D Models ◽  
Nickel Titanium ◽  
Element Analysis ◽  
Torsional Resistance ◽  
Cad Cam ◽  
Flexural Resistance ◽  
Cam Software

AIM: To compare and evaluate the influence of thermomechanical treatment of Protaper Gold file versus Protaper Universal file during testing of bending and torsion using finite-element analysis. METHODS: Two nickel-titanium NiTi rotary files (ProTaper Gold and ProTaper Universal) were used in this study. The files were imaged using stereomicroscope to produce 3D models. The behaviour of the instrument during bending and torsion was numerically analysed in CAD/CAM software package. RESULTS: Under bending, ProTaper, Gold showed higher flexibility and flexural resistance than ProTaper Universal. The highest stress was related at the cutting edge of both files. While during testing of torsion, the maximum amount of stresses was related to the base of the flutes in both files. ProTaper Gold showed higher torsional resistance than the ProTaper Universal file. CONCLUSION: Thermomechanical treatment improved the mechanical response (bending and torsional resistance) of NiTi files.

scholarly journals Dynamics of Photogenerated Charge Carriers in TiO2/MoO3, TiO2/WO3 and TiO2/V2O5 Photocatalysts with Mosaic Structure

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1022
Author(s):  
Alexander I. Kokorin ◽  
Tatyana V. Sviridova ◽  
Elizaveta A. Konstantinova ◽  
Dmitry V. Sviridov ◽  
Detlef W. Bahnemann
Keyword(s):  
Light Exposure ◽  
Low Cost ◽  
Energy Levels ◽  
Charge Trapping ◽  
Bactericidal Effect ◽  
High Reactivity ◽  
Charge Carriers ◽  
Light Illumination ◽  
Uv Illumination ◽  
Photocatalytic Material

Titania is a widely used photocatalytic material possessing such advantages as low cost and high reactivity under the ultraviolet light illumination. However, the fast recombination of photoexcited charge carriers limits its application. Herein, we have synthesized original nanomaterials with mosaic structures that exhibited well-defined heterojunctions and new properties. Using SEM, XRD, EPR spectroscopy, photocatalytic measurements, and photoinduced pathphysiological activity of these photocatalysts, we studied the processes of charge carrier accumulation in TiO2/MoO3, TiO2/WO3, and TiO2/V2O5 under in situ UV illumination with emphasis on the charge exchange between energy levels of these nanosized semiconductors. It is shown that the accumulation of photoinduced charges occurs in two forms (i) filled electron traps corresponding to Ti4+/Ti3+ levels and (ii) Mo5+ centers, both forms contributing to the photoinduced biocide activity of the samples. This work demonstrates that light exposure of heterostructure photocatalysts with mosaic surfaces produces different types of charge-trapping centers capable of interacting with molecular oxygen yielding peroxo species, which provide long-life light-induced ”self-cleaning” behavior. Such photoaccumulating materials open new opportunities in developing light-driven self-sterilization structures exhibiting a prolonged bactericidal effect up to 10 h after stopping light exposure.

scholarly journals Damage Detection of Common Timber Connections Using Piezoceramic Transducers and Active Sensing

Sensors ◽  
2019 ◽  
Vol 19 (11) ◽  
pp. 2486 ◽  
Author(s):  
Fang Han ◽  
Jinwei Jiang ◽  
Kai Xu ◽  
Ning Wang
Keyword(s):  
Damage Detection ◽  
Lead Zirconate Titanate ◽  
Failure Modes ◽  
Low Cost ◽  
Energy Levels ◽  
Stress Waves ◽  
Active Sensing ◽  
Timber Structures ◽  
Signal Energy ◽  
Timber Connections

Timber structures have been widely used due to their low-cost and environmental-friendly properties. It is essential to monitor connection damage to ensure the stability and safety of entire timber structures since timber connection damage may induce catastrophic incidents if not detected in a timely manner. However, the current investigations on timber connections focus on mechanical properties and failure modes, and the damage detection of timber connection receives rare attention. Therefore, in this paper, we investigate the damage detection of four common timber connections (i.e., the screw connection, the bolt connection, the decussation connection, and the tooth plate connection) by using the active sensing method. The active sensing method was implemented by using a pair of lead zirconate titanate (PZT) transducers: one PZT patch is used as an actuator to generate stress waves, and the other works as a sensor to detect stress waves after propagating across the timber connection. Based on the wavelet packet energy analysis, the signal energy levels of received stress waves under different damage extent are quantified. Finally, by comparing the signal energy between the intact status and the damage status of the timber connection, we find that the energy attenuates with increasing severity of the connection damage. The experimental results demonstrate that the active sensing method can realize real-time monitoring of timber connection damage, which can guide further investigations.

Tuning the hygro-mechanical response of paper-based systems using glycerol

2020 ◽  
pp. 1045389X2094716
Author(s):  
Isaias Cueva-Perez ◽  
Roque Alfredo Osornio-Rios ◽  
Aurelio Dominguez-Gonzalez ◽  
Ion Stiharu ◽  
Angel Perez-Cruz
Keyword(s):  
Dynamic Response ◽  
Resonance Frequency ◽  
Mechanical Response ◽  
Water Solution ◽  
Low Cost ◽  
Mechanical Systems ◽  
Lumped Parameter Model ◽  
Glycerol Water ◽  
Energy Harvesters ◽  
Lumped Parameter

In recent years, the need for portable, low-cost, and eco-friendly devices for testing and monitoring has arisen. Paper-based devices have emerged as a response to these needs due to the properties induced by capillarity, flexibility, disposability, and biodegradability. In this work, the authors explored the possibility of tuning the hygro-mechanical response of paper-based cantilever beams using glycerol. A lumped-parameter model with non-linear stiffness is used to describe the dynamic response of the beams using three parameters. An experimental method based on resonance frequency tests is used to study the influence of glycerol on the dynamic response of four different beam configurations. The obtained results demonstrate that the resonance frequency of paper-based mechanical systems can be easily tuned by the imbibition of a glycerol–water solution. This study could lead to the development of tunable paper-based mechanical systems for specific applications such as energy harvesters and hygro-mechanical-based sensors.

Cast NiTi Shape-Memory Alloys

2004 ◽  
Vol 855 ◽  
Author(s):  
Alicia M. Ortega ◽  
Carl P. Frick ◽  
Jeffrey Tyber ◽  
Ken Gall ◽  
Hans J. Maier
Keyword(s):  
Shape Memory Alloys ◽  
Shape Memory ◽  
Grain Orientation ◽  
Mechanical Response ◽  
Complex Geometry ◽  
Low Cost ◽  
Orientation Distribution ◽  
Scanning Calorimetry ◽  
Cast Material ◽  
Niti Shape Memory Alloys

ABSTRACTThe purpose of this study is to investigate the structure and properties of polycrystalline NiTi in its cast form. Although it is commonly stated in the literature that cast NiTi has poor shape-memory behavior, this study demonstrates that with appropriate nano/micro structural design, cast NiTi possesses excellent shape-memory properties. Cast NiTi shape-memory alloys may give rise to a new palette of low-cost, complex-geometry components. Results from two different nominal compositions of cast NiTi are presented: 50.1 at.%Ni and 50.9 at.%Ni. The cast NiTi showed a spatial variance in grain size and a random grain orientation distribution throughout the cast material. However, small variances in the thermo-mechanical response of the cast material resulted. Transformation temperatures were slightly influenced by the radial location from which the material was extracted from the casting, showing a change in Differential Scanning Calorimetry peak diffuseness as well as a change in transformation sequence for the 50.9 at.%Ni material. Mildly aged 50.9 at.%Ni material was capable of full shape-memory strain recovery after being strained to 5% under compression, while the 50.1 at.%Ni demonstrated residual plastic strains of around 1.5%. The isotropic and symmetric response under tensile and compressive loading is a result of the measured random grain orientation distribution. The favorable recovery properties in the cast material are primarily attributed to the presence of nanometer scale precipitates, which inhibit dislocation motion and favor the martensitic transformation.

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