This article deals with the impact and how to improve the Fatigue strength of Spring steel. In this regard, the basic and modern methods that include reducing the size of inclusions, decrease grain size, reducing the depth of decarburization, increasing the surface quality and desirable microstructure due to heat treatment are investigated and compared. In relation to the Fatigue strength of Spring steel, the microstructure of tempered martensite or fine bainite is used in the industry. The experimental results show that the multi-phasing of Spring steel from the microstructures of tempered martensite, fine bainite and retained austenite in Q&P and Q&B heat treatment methods or a combination of these two methods will bring the best micro-alloy microstructure for Spring steel. The concerned evaluation methods were: different microstructures caused by heat treatment and reducing the size of non-metallic inclusions in steel. The experimental results show that if the steel is clean (free of inclusion), the microstructure would play a dominant role in increasing the Fatigue life.

Compression Springs were prepared from Cr-Si high strength Spring steel and coated with pure Zn and Zn­ Ni by electroplating process. The effect of baking after electroplating as well as applying an electroless nickel interlayer on the Fatigue and Fatigue corrosion of the Springs was investigated. The results were analyzed using weibull statistical model. A considerable improvement (8%) in Fatigue life of the electroplated Springs with Zn-Ni was observed in the presence of Ni interlayer. In addition, baking of these electroplated Springs improved Fatigue life by 4%. The Fatigue life under salt spraying conditions, however, has demonstrated remarkable reduction by 40%, 34% and 30% for Zn-Ni plating, backed and unbaked Zn-Ni plating containing Ni interlayer, respectively.

The investigation of SUP9 steel under the hot-rolling conditions for applications to leaf Spring suspension focused on its tensile and Fatigue crack growth (FCG) properties. In order to investigate the tensile properties, tensile specimens were fabricated in the longitudinal-transverse (LT) direction. Furthermore, in order to evaluate Fatigue crack growth (FCG) behaviour, compact tensile (CT) specimens with different crack plane orientations in both the LT and transverse-longitudinal (TL) directions were employed. Microstructural and fractographic analyses were conducted using optical microscope (OM) and scanning electron microscopy (SEM). The hot-rolling process reduced the interlamellar spacings of Fe3C, enhancing the tensile properties through strain hardening. A high yield-to-ultimate strength ratio (~0.623) indicates excellent plastic deformation capability and resistance to Fatigue crack growth, making SUP9 steel suitable for the leaf Spring suspension system. Furthermore, the exponential crack growth rate constant, m, was found to be 3.066 in the TL direction and 3.265 in the LT direction, indicating that cracks propagate more rapidly in the LT orientation. Additionally, non-metallic inclusions, such as spherical oxides and MnS precipitates in LT specimens, were observed to facilitate faster crack growth in the transverse direction.

Introduction: Water distribution uniformity is a key in pressurized irrigation systems. Pressure fluctuations due to topographical changes, local and frictional head losses, and different water uses are considered of great concerns. Any mechanical device with the ability to keep an almost constant flow delivery, irrespective of the pressure fluctuations is of great practical importance. In this regard, a flow control valve is a useful tool. A flow control valve is a mechanical choked orifice plate structure including a float-Spring mechanism inserted in an ordinary orifice (Zhang and Wang 2015). Such a valve is not yet produced commercially. In this study, the effect of the Spring elasticity mainly due to Spring Fatigue is investigated experimentally on the valve performance. Also, the changes in the installation location of the float, when the valve is in rest condition, may affect its performance. To quantify this effect a detailed experimental plan was performed...

Introduction: One of the most difficult procedures in orthodontics is the treatment of skeletal open bite. This malocclusion is characterized by back ward rotation of mandible, an obtuse gonial angle, an increased anterior facial height, and a E long face appearance. The treatment strategy of skeletal open bite has been mainly based on vertical growth inhibition, forward autorotation of mandible, and intrusion of posterior dent alveolar structures. Early treatment of this malocclusion is of great interest because the therapeutic approach is functional before growth has been completed and is surgical afterwards. Posterior bite-blocks are one of the functional appliances which are commonly used. The purpose of this study was to evaluate the effect of Spring loaded posterior occlusal bite block (SLPOBB) on dento-facial structures in patients with skeletal open bite. Materials & Methods: In this clinical trial study, our sample group consisted of 23 skeletal open bite subjects (9 males and 14 females) having a mean age of 9.8, treated by SLPOBB until the open bite was completely dissolved and a favorable overjet was achieved. Cephalometric tracing was carried out on the lateral cephalograms taken prior to and after treatment. The data were analyzed using paired t-test to determine significant changes (a=0.05).Results: Skeletal changes: A statistically significant increase in SNB, ArGoGn, mandible length, anterior facial height, UFH, LFH, and posterior facial height was found.Decrease in ANB, Palatal plane/MeGo, SArGo, SNGoAr, and Y-Axis was also significant. Dental changes: The results revealed a significant increase in Upperl/Palatal plane height, Lower1/GoMe height & Upper 6/Palatal plane height and a decrease in Lower1/GoMe angle. Conclusion: SLPOBB was found to be effective in treatment of skeletal open bite by: 1) A significant decrease of mandibular posterior angles, an increase of posterior facial height, and upward and forward rotation of mandible. 2) Intrusion of mandibular first molars. 3) Extrusion of anterior dentoalveolar height, and lingual inclination of lower incisors.

Spring viraemia of carp virus (SVCV), a negative sense single stranded RNA virus of the family Rhabdoviridae, is the causative agent of a highly contagious SVC disease that primarily affects the common carp (Cyprinus carpio), an economically important fresh water fish species with world-wide distribution. SVCV has also been reported to cause disease in other fishes such as Poeciliidae, Esocida, Centrarchidae, Siluridae and salmonidae. There are several diagnostic tests for the detection of SVC virus, however, the tests have not been validated. The reverse transcriptase – polymerase chain reaction (RT-PCR) techniques have been developed and validated representing a powerful tool for detection of RNA. One of the most important aspects isolating RNA is to prevent degradation of the RNA during the isolation procedure. In this study, we explored the efficiency of protocols for RNA isolation from the SVCV strain 56/70.For RNA isolation, we compared four protocols, two guanidine isotiocyanate phenol – chloroform based protocols (RNX – Plus Iran, Iq2000 kit Taiwan) and two column based protocols (Cinnapure RNA Iran, high pure viral RNA kit, Roche Germany) that were commercially available. The results showed that the column based protocols, Roche method and Cinapure performed better than other methods with the yields of 31.76 ng/ml, 16/21 ng/ml, respectively. Each protocol yielded good quality of total RNA bands (480 bp) being observed in agarose gel electrophoreses but was not observed in IQ2000 kit. Amount of total RNA isolated was lower for IQ2000 kit Protocol. Further, the RNA being extracted from SVC by column based protocol method were resulted in successful amplified using RT-PCR method.

Barmejamal Spring is located in northeast of Ahwaz, Khuzestan Province, Iran. The catchment area of the Spring consists of the northeast and southwest flanks of the Koh-e-Safid anticline, which is made up of karstic calcareous Asmari formations. There are sinkholes, caves, and other karst landforms in the catchment area. The existence of several faults has brecciaed Barmejamal Spring karst aquifer that may have caused karstification to occur in parallel fracture systems. For the purposes of this study, pH and water temperature were measured on a weekly basis for a period of 12 months and water samples were analyzed for major anions and cations. Flow rate was measured on a daily basis during the recession, and weekly during the rest of the study period. Using the PHreeqc 2.6 computer model, the partial pressure of carbon dioxide and the saturation index of calcite and dolomite were also estimated. Three distinct periods belonging to three recession coefficients (\1, \2, \3) were observed in the hydrograph of the Barmejamal Spring. No considerable differences were observed between the first and second recession coefficients. Base flow for \1, \2 and \3 constituted 49%, 75.34%, and 100% of the total flow in the first and second recession periods and in the precipitation period, respectively. The variation of specific conductance, calcium and bicarbonate concentrations, and calcite saturation indices were not significant throughout the study period. The morphology and geology of the Barmejamal Spring catchment area and the data from hydrograph and chemographs show that the hydrologic system is of the diffuse-conduit flow type.