Since the first experiments with plasma focus facilities in 1960's. These devices are known as intense sources of neutron when the working gas contains deuterium with a proper density. Most of the emitted neutrons are produced by D-D reactions, but the mechanism of these reactions is not still clear completely. In this paper, the results of experimental investigations of neutron emission characteristics in "Dena" plasma focus facility (Filippov type, 90 kJ, 25 kV) over a range of discharge voltages and pressures are presented. Out working gases are D2 & D2+%1 Kr, two different conic and flat insert anodes were employed. We have simultaneously measured the total emissions in our experiments for analyzing the neutron generation mechanism in this device. We have found the upper & lower pressure limits and the optimum pressure for neutron generation, and we have observed the double pluses structure of neutron signal for the first time in this device. Form the experimental results, it seems that both thermonuclear & no thermonuclear mechanisms are always present in neutron generation, but their contribution in the total yield is strongly dependent on experimental conditions (initial pressure, discharge voltage, gas admixture, etc.) It was found that the range of variation of total neutron yield and neutron emission anisotropy factor for experiments with D2+%1 Kr is wider than experiments with D2, and the best neutron emission results belongs to discharges in D2+%1 Kr with a conic insert anode. By employing D2+%1 Kr with a conic insert anode, and varying pressure between 0.3-2 torr at a discharge voltage of 16 kV, it can be deduced that in low pressures (<0.5 torr) the role of beam - target interaction mechanism in neutron production is important, and its importance decreases with pressure, around the optimum pressure (0.86 torr) the GPM mechanism has the major effect on neutron generation, and at high pressures the thermonuclear mechanism plays the major role. Furthermore, the behavior of the neutron yield and anisotropy factor with discharge energy at a pressure near optimum (0.84 torr) was studied and it was found that at low energies anisotropy factor is relatively high and decreases sharply by increasing the energy, From the experimental results, the? index in the empirical neutron yield scaling law was found about 3.62 for D2 +%1 Kr and 3 for D2.

Temporal flow characteristics of a 3D centrifugal impeller suction system were numerically studied in vacuum conditions. The blockage of the high-speed rotating impeller appeared, which greatly dropped the suction of the layer suction device. The temporal flow characteristics of the 3D centrifugal impeller suction system were worthy of attention in vacuum conditions. Separation vortices were generated near the blade suction surface. The blocking mechanism of the passage was further analyzed at different extremely low flow rates through the time-space evolution of the streamline. The Q-criteria was introduced to analyze the vortex evolution within the fluid domain of the impeller. Vortex evolution law was captured—the vortices always generated near the suction surface of the blade and moved to the pressure surface of the adjacent blade in the same passage and disappeared. The uniform distribution of three stall cells was captured through the diagram of turbulent kinetic energy. The flow rate increased, and the vortex evolution period gradually decreased. The comparison of pressure fluctuations in different conditions further demonstrated the flow mechanism at the vacuum flow rate was different from that at low flow rates. The sharp increase of pressure fluctuations near the blade pressure surface was consistent with the phenomenon near the suction surface. The pressure fluctuation at extremely low flow was mainly composed of scattered fluctuations caused by fluid separation. The steady and unsteady characteristics described the internal flow characteristics of this suction system at vacuum-flow rates. Theresults provide a profound design for vacuum cleaners.

Today, many researchers have focused to use of composite materials in various industries. Most of the composites used in industry are structurally sandwich composites. Sandwich composites consist of three parts: shells, core and adhesive materials. Sandwich structures are mostly used where the weight and volume of the structure is superior to its strength. Therefore, if sandwich structures can be strengthened in some way without huge increase of weight, they will be a very good alternative for all types of metal and composite structures. One of the issues in the field of pressure vessels and composite bodies is the study of their endurance in the face of external pressure. Due to the creation of unstable buckling in tanks under external pressure, the buckling is always considered as the main mechanism of their failure.The current study aims to investigate the core of sandwich structures by modeling the tanks and bodies under external pressure of these structures using the finite element method. Two modes were examined for modeling: one with a solid foam core and the other with a honeycomb-shaped core (trapezoidal). Each of these modes was modeled in two distinct materials, as well as three various dimensions and sizes, which were first derived linearly by the first buckling mode for each of the modes; The problem was then nonlinearly analyzed for the most crucial situation with coefficient of initial geometric disturbances . By analyzing prior research in this subject, the results of finite element analysis were confirmed. The usage of sandwich composite constructions in the face of external pressure conditions, according to the findings, can be highly useful.

Various researches on laboratory and field scale illustrate that manipulating the ionic composition and the ion concentration of injected water can affect the efficiency of water flooding and the interaction of injected water with rock and other fluids present in porous media. The objectives of this paper are to investigate parameters that affect low salinity water flooding; mainly the effect of injecting water salinity on and the potential of low salinity water flooding for oil recovery in secondary recovery mode are studied. The effect of pH and differential pressure across the core are used to explain the mechanism of fine migration phenomena. The recovery results of formation water injection were compared for the seawater, formation water with a salinity of 0.1 and 0.01, and when divalent ions were removed from the formation water with a salinity of 0.01 to investigate the effect of divalent ions on oil recovery. Different types of crude oil were used for investigating the effect crude oil properties on oil recovery. Seawater injection resulted in lowest oil recovery of 2.6% and the reduction of water salinity of formation water from 0.1 to 0.01 resulted in an improvement of 4% and 7.7% in oil recovery respectively. Removing divalent ions from the injected water decreased the improving effect of low salinity water flooding. In addition, both types of crude oil responded to low salinity flooding and no straight correlation was seen between acid number and the improving effect of low salinity water flooding.

Pore pressure is defined as the pressure of the fluid inside the pore space of the formation, also known as the formation pressure. When the pore pressure is higher than hydrostatic pressure, it refers to as overpressure. Overpressure can make many problems such as kicks, blowouts, wellbore instability, hole washouts and loss of drilling mud circulation. Overpressure is generated due to different mechanisms; such as, compaction disequilibrium, oil to gas generation, buoyancy effect and lateral transfer. Each mechanism effects on exceed pressure in a significant way. So far, several methods have been proposed in pore pressure prediction using well logs and seismic data. Each method relies on a consideration that over pressure is resulting from a specific mechanism as the main factor, and it is also provided an empirical formula for estimation of pore pressure. Hence, geological studies to understand the overpressure generation mechanism and also choose the appropriated pore pressure estimation method are very important. The main objective of this study is to determine the mechanism of high pressure using well log information and provides the best method of estimating the pore pressure in one of hydrocarbon fields in southern Iran. To obtain this goal, the overpressure mechanism generation is studied from sonic log, density log, pore pressure and vertical effective stress information. The results suggest more disequilibrium compaction as the main mechanism and less unloading mechanism behind the overpressure. So, the Eaton and Bowers methods are used to estimation pore pressure and the results show agreement with the pore pressure prediction from formation pressure test.

This study investigated the development and evaluation of an automatic feeder control system for sugarcane planters. The primary objective was to address limitations in existing machines and enhance their performance by introducing precise control of cane feeding.

The automatic feeder control system was equipped with three types of sensors, including a Load Cell Sensor that directly measures the weight of sugarcane on the feeder table. This feature provides a real-time assessment of cane availability. The Hydraulic Oil Pressure Sensor monitored the pressure within the hydraulic system that drives the feeder mechanism. Variations in pressure served as an indirect measure of the force applied to the cane during the feeding process. The Ultrasonic Distance Sensor employed ultrasonic waves to estimate the distance between the sensor and the sugarcane pile. Nevertheless, some limitations concerning accuracy and response time were identified. A microcontroller served as the central processing unit, receiving sensor data and generating control signals to regulate the feeder mechanism. This allowed for automation and eliminated the need for a manual operator. The performance of the automatic feeder control system was evaluated against a manual control method operated by a human.

The evaluation focused on three key aspects: cane spillage, planting quality, and control stability. Cane Spillage: the amount of sugarcane inadvertently dropped during the planting process. Automatic control methods using a load cell and hydraulic oil pressure sensor reduced spillage similarly to manual control, averaging approximately 8.8 t ha-1. The ultrasonic sensor resulted in significantly lower spillage, achieving 7.4 t ha-1. However, its limited accuracy and responsiveness led to undesirable gaps between the planted canes. Planting Quality: The implementation of automatic control techniques utilizing load cells and hydraulic oil pressure sensors successfully ensured uniform spacing between planted canes, achieving results comparable to traditional manual methods. Due to its shortcomings, the ultrasonic sensor created gaps between the planted canes, undermining the overall quality of the planting process. Control Stability: The method utilizing hydraulic oil pressure sensors exhibited limitations in maintaining consistent control under varying operational conditions. This stemmed from temperature-dependent changes in oil viscosity, which affected the pressure readings and ultimately the control signal. Based on the evaluation results, the load cell control method emerged as the most favorable option for automatic feeder control. It delivered performance that matches manual control in terms of cane spillage reduction and planting quality, all while eliminating the need for an operator. The hydraulic oil pressure sensor method, although effective in some aspects, presented challenges due to oil viscosity variations. The ultrasonic sensor showed promise for reducing spillage; however, it ultimately fell short due to its inability to accurately and swiftly detect the availability of cane, resulting in gaps between planted canes. A separate assessment was carried out to compare manual cultivation with an automatic control method based on weight measurements using a load cell. This evaluation revealed significant differences (p < 0.01) in billet weight, the number of billets utilized, and one-sided gaps between the two methods. However, no significant difference was observed in terms of two-sided gaps.

This study successfully designed and implemented an automatic feeder control system for sugarcane planters. The load cell control method emerged as the most effective solution, successfully eliminating the need for operators while ensuring high standards of planting quality and efficiency. Additional research could explore advancements in sensor technology and control algorithms to further enhance the performance of automatic feeder control systems.

The aim of this study was to analyze the mechanism is precipitation Comprehensive Iran. For this purpose the daily precipitation data of 483 synoptic and climatology stations arranged. In this study, a comprehensive annual rainfall is said to have a minimum rainfall and above, 50% sequence coverage and have at least two days. Winter surround Iran on the condition of rainy days were extracted and examined. Then, to review and analyze the mechanism of atmospheric precipitation comprehensive synoptic and dynamic parameters such as moisture flux, vortices, ground level pressure, Geopotential, meridional and zonal wind component for the levels of 1000, 850, 700 and 500 HP studied and analyzed was. The results of this study showed that the widespread mechanism of dynamic and synoptic Winter country most affected by the composition of the atmosphere patterns such as the Mediterranean low pressure - low pressure core Persian Gulf, Iran, Central High East Europe closed low pressure, low pressure Urals - the Middle East, high pressure, low pressure Saudi Arabia - High pressure belt Europe and Siberia - Iran's low-pressure center. However most of the winter precipitation of moisture flux feed barley middle-Level interaction, particularly levels of 850 and 700 HP respectively. It was while change 500 hPa atmospheric dynamical mechanism is an important role in Iran's winter inclusive.

In this paper, a setup for performing dynamic flow experiments was prepared. A set of natural depletion tests were done to investigate the effects of pressure depletion and the initial asphaltene content of crude oils on asphaltene deposition in porous media using two live oil samples of Iranain reservoirs. The results of these experiments, which were done in constant rate and three pressure steps, show that the asphaltene deposition occurs by decreasing pressure in the vicinity of bubble point pressure and the main mechanisms are surface deposition, pore throat plugging and in some period the entrainment of the particles via the flow of oil is observed. According to the experiments, in case of the oils with less asphaltene content, the dominant mechanism is surface deposition, and the rate of deposition is uniform, while using the crude oil with higher asphaltene content, the pore throat plugging mechanism has more important role in the permeability reduction of reservoir rock.

The aim of the present study was comparison of plantar pressure distribution and ground reaction force during walking between prefabricated shoes with hydrodynamic mechanism and EVA sport shoes. In the current study, 10 healthy male individuals participated. A special shoe with specific ways for liquid flow was made for the present study that was capable of reducing pressure from damping mechanism. Also, an EVA shoe was used for comparison as reference shoe. Ground reaction force and plantar pressure distribution were measured using Pedar insole system. Data analysis was performed using Pedar X software and in eight regions of foot. The results of the present study showed that the special shoe with hydrodynamic mechanism could effectively reduce load in rear foot, forefoot, and toe regions. According to the results, damping effect of liquid shoe following impact force can effectively reduce the pressure and force in high risk regions of the foot.

Many models are proposed to predict flux decline in membrane ultrafiltration, but since these models have limiting assumptions, they are not applicable to all solutions. The present study modeled fouling in skim milk concentration process using proposed equations for the main mechanisms of fouling, including complete blocking mechanism, intermediate blocking mechanism, standard blocking mechanism and cake filtration mechanism. These models then were compared with experimental data at 50, 100, 150, 200 and 250 kPa trans-membrane pressures to investigate the effect of trans-membrane pressure on flux decline. Based on the results obtained here, it was found that predictions of cake filtration model were in good agreement with experimental data, while those of standard blocking model were in poor agreement. Complete blocking mechanism was not capable of predicting flux data using CurveExpert Professional. With decreasing trans-membrane pressure, the differences between experimental data and models decreased. The results also showed that the second mechanism responsible for flux decline was intermediate blocking model. In fact, cake filtration mechanism and intermediate blocking mechanism are the two main mechanisms responsible for fouling in skim milk concentration process. Moreover, the results obtained from modeling of resistance showed that the cake layer resistance was the main resistance to flow, which was in accordance with what we had expected from accumulation of protein and fat molecules on the surface of the membrane. All in all, the cake filtration mechanism is the main mechanism for predicting flux decline, and it is expected that this model in combination with intermediate blocking model, would result in the best prediction of fouling phenomena in milk concentration process.