An experimental study on pulsating Heat pipe (PHP) is presented in this work. A closed loop PHP with a single U turn is fabricated and tested. The transient and steady state experiments are conducted and operating temperatures are measured. The experiments are carried out for different working fluids, Heat Input and for different evacuation levels. The derived parameters include thermal resistance and Heat transfer coefficient of PHP. The results of these experiments show an intermittent motion of the working fluid at lower Heat Input. The temperature difference between evaporator and condenser at steady state is found lower for acetone compared to water, ethanol and methanol. Lower value of thermal resistance and higher value of Heat transfer coefficient are observed in case of acetone compared to water, ethanol and methanol. Lower values of temperature difference between evaporator and condenser and thermal resistance and higher value of Heat transfer coefficient are observed at atmospheric conditions of operation of PHP compared to evacuation conditions. The Power Spectral Density Analysis is also carried out on the results of these experiments using FFT technique to analyse the pulsating motion of the fluid in a PHP. In the Power Spectral Density analysis, the frequency distribution of temperature variation in PHP was observed over a wider range, signifying the periodic motion in the fluid flow of the liquid slug and vapour plug. This characteristic frequency corresponded to the characteristic time for a couple of adjacent vapour plug and liquid slug passing through a specific local wall surface in a PHP.

The influence of Heat-Input and pre-Heat treatment on the structure, mechanical and corrosion behavior of 2205 duplex stainless steel joint by means of GMAW process was the goal of this study. In this regards, the welding process was done using different Heat Input in the range of 0. 6 to 1. 4 kJ/mm and different pre-Heating treatments in the range of 25 to 100 oC. The microstructural properties of prepared samples were evaluated using x-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. Based on archived results, the microstructure of as-welded samples were combinations of Widmaneshtaten austenite which nucleated from boundaries and growth toward central part of ferrite grains. By increasing the Heat-Input, the percentages of ferrite and austenite phases decreased and increased, respectively. In this condition, the highest value of strength and ductility was achieved in as-weld samples with medium (1. 0 kJ/mm)Heat-Input. The corrosion studies showed that the Heat-Input has negligible effects on corrosion behaviorof 2205 duplex stainless steel joint. It was also found that the pre-Heating treatment has adverse effect on the mechanical properties of the junction.

Bone fracture occurs as a result of accident, old age and disease. Generally bone fracture treatment consists of stabilizing the fractured bone in the right position. In complex fractures, stabilizing internal and external tools and equipment is used to stabilize the fractured bone in position. Bone drilling is required in order to connect fixating devices. The forces required for chip formation increase the temperature during bone drilling. The phenomenon of thermal necrosis of the bone occurs if the temperature exceeds 47oC. Thermal necrosis inhibits bone fixation and causes the wrong bone healing.In this study it has been attempted to calculate the Heat of drilling process using the machining theory and estimate the share of Heat Input to the bone by the Weiner theory. Drilling tests conducted on samples of bovine bones and temperature changes in the location of the hole are measured and, using inverse conduction Heat transfer method, the Heat Input is calculated and compared with the theoretical Heat. Results showed that the experimental and theoretical Heats at different processing conditions are close to each other and revealed that the machining and Weiner theories are able to predict the Heat Input to the bone and temperature changes in the position of the hole.

In this experimental work, AISI 304 was welded via metal inert gas (MIG) welding process with Argon (Ar) as shielding gas. In the present study, AISI 304 was subjected to different Heat Input using a standard 308L electrode. Weld quality i.e. ultimate tensile strength, toughness, microhardness, and microstructure of AISI 304 were examined. Microstructures of welded joints were studied using scanning electron microscopy (SEM), linked to the SEM was used to determine the chemical composition of phases formed at the joint interface and from the result, it was revealed that at low Heat Input ultimate tensile strength is higher than those at medium and low Heat Input. From the result, it was also observed that grain coarsening extent in the HAZ increases with an increase in the Heat Input. It was also found that the fractures of toughness samples were brittle in nature which shows the low ductility and brittle fracture. Weld zone microstructure exhibited skeletal δ-ferrite in austenite matrix with various ferrite contents. Microhardness of weld bead was found to decrease with increases in the Heat Input. It was also observed that at medium Heat Input there was an improvement in tensile strength, elongation, and hardness due to finer grain structure and smaller inter-dendritic spacing.

In this study, the effect of Heat Input on microstructure and mechanical properties of magnesium alloy, AZ91, were investigated. The butt welding was carried out at three different Heat Inputs (269, 452, and 657 J/mm), using a tungsten arc welding process under the protection of inert gas (GTAW). Microstructure observation with optical (OM) and scanning electron, microscopes (SEM) showed that with an increase of the Heat Input, the grains both in the fusion zone and the Heat-affected zone coarsen and the width of the Heat-affected zone increased. Moreover, an increase of the Heat Input up to 657 J/mm resulted in a decrease of the continuous Mg17Al12 phase and an increase of the granular (particularly in weld area) and randomly dispersed. The results of tensile tests show that at high Heat Input the welding strength will decrease to 114 MPa, due to creation of gas voids in the welding area. This value is 21% less than that observed for lower Heat Input (269 J/mm).

The cladding of plain carbon steel with stainless steel is desired in industry because increase of corrosion resistance and reduction of economic costs. The cladding using tungsten electrode arc welding and shielding gas is in more attention due to unique features such as high quality and good adhesion to the base metal. In this study ER309L austenitic stainless steel was used as the primary layer and E316L as the final layer, on the SA516- Gr70 steel as well as the effect of Heat Input at four Heat level (574.5 j/mm, 609, 673, 743.5) was investigated. The ferrite was measured by a ferrite meter and Cr-Ni equivalent chart. From these results the amount of ferrite was higher at minimum Heat Input with respect to other Heat Inputs. The corrosion resistance of the samples was evaluated. According to the results, it was observed that increasing the Heat Input reduced the corrosion resistance and the highest corrosion resistance was observed at minimum Heat Input (574.5 j /mm).

This paper aims at investigating the effect of Heat Input in resistance spot welding on microstructure and mechanical behavior of 2304 duplex stainless steel, as a promising candidate for automotive application. The results showed that due to rapid cooling rate inherent to resistance spot welding, the ferrite-austenite phase balance is destroyed and nitride-type precipitates are formed within the ferrite grains. The amount of austenite in the weld nugget was a function of welding current, as the most important factor affecting welding Heat Input. Increasing welding current increased the austenite volume fraction from 4 to 18%. Moreover, the nitride precipitation was reduced upon using higher welding currents. Investigation of weld mechanical performance during the tensile-shear loading showed that increasing welding current enhances both load bearing capacity and energy absorption capability. The maximum achievable peak load and energy absorption of 2304 duplex stainless steel resistance spot welds were 25 kN and 40 J, indicating a superior weldability.

To evaluate the effect of nitrogen and water withholding in vegetative growth stage of corn on efficacy of nicosulfuron and 2,4-D+ MCPA an experiment was conducted as a factorial arrangement in a randomized complete block design with three replications at Tarbiat Modares University in 2017. The first factor contained four treatments including application of nicosulfuron, 2,4-D+ MCPA, weed free and weed infested as control. The second factor consisted of normal irrigation and water withholding from 4 to 8 leaf stage. Third factor contained either urea application or no fertilizer application. Normal irrigation and nitrogen fertilizer application significantly increased nicosulfuron and 2,4-D+ MCPA efficacy in weed control and total weed dry weight decreased to 341 and 361 g.m-2 respectively compared 1370 g.m-2 as weed infested. Nicosulfuron and 2,4-D+ MCPA reduced weed total dry weight significantly under irrigation withholding. Grain yield increased with application of nitrogen and nicosulfuron. Grain yield was higher with application of 2,4-D+ MCPA than nicosulfuron without nitrogen application under irrigation withholding. Application of nicosulfuron with nitrogen application provided satisfactory weed control and increased grain yield.