The Influence of Sandblasting Process Parameters of Aerospace Aluminium Alloy Sheets on Adhesive Joints Strength

In this study, the influence of sandblasting process parameters as a surface preparation method on the strength of single-lap adhesive joints of EN AW 2024 T3 aerospace aluminium alloy sheets was determined. Eleven sets of sandblasting parameters were used, which were determined according to a determined experimental plan. The variable factors in the sandblasting process were pressure, nozzle distance, and workpiece displacement speed. The sand jet incidence angle was constant. Garnet 80 E+ was the abrasive material that was used. The joints were made using an epoxy adhesive composition of Epidian 5 epoxy resin and a PAC curing agent. The influence of the surface preparation method on the surface roughness and contact angle to determine the surface free energy was evaluated. The shear strength of the adhesive joints was also determined, which finally allowed the evaluation of the applied surface treatment variants. The obtained results were subjected to statistical analysis, which indicated that the highest shear strength of the adhesive joints was obtained for samples whose surfaces were treated by sandblasting at parameter configurations in which the pressure was 5–6 × 105 Pa; the distance between the nozzle and the sandblasted surface should not be greater than 97 mm, and the speed at which the workpiece moves in relation to the nozzle should not be greater than 75 mm/min.

The result of the influence of center pivot irrigation machine operations on rain (irrigation) intensity

The water consumption through the nozzle or water pressure through the nozzle at the given water thickness (У,min) the two technological parameters, the pressure of the nozzle (X1, PSI) and the rotational speed of the nozzle (X2, m/min) are used to determine the state of the impact at 8 mm nozzle. The experiment was determined under laboratory conditions on a Low Energy Nozzle (LEN). The experiment was conducted in the ‘’ Irrigation machinery and equipment design’’ laboratory of the School of Engineering and Technology of the MULS using the ‘’Low pressure nozzle distribution radius and rain intensity measuring equipment’’. The maximum intensity of water supplied by the nozzle is 1.727 mm / min or the maximum pressure is 30 PSI and the minimum flow rate is 0.313 mm / min. The pressure regulator at 20 min was at a value of 20 PSI, and the transition speed was at a maximum of 3 m / min. Бороожуулах эрчимд машины ажиллах горим нөлөөлөх байдлыг тодорхойлсон дүн Бороожуулах хошуугаар өгч байгаа усны зарцуулгын хэмжээ буюу өгсөн усны зузаанд (Y, мм) хошуугаар гарах усны даралт , машины тойрох хурд гэсэн технологийн хоёр параметр дангаараа болон хавсран үзүүлэх нөлөөллийн төлвийг тодорхойлох туршилтыг 8 мм голчтой бороожуулах хошуун дээр лабораторийн нөхцөлд тодорхойлов. ХААИС-ийн ИТС-ийн “ Усалгааны машин, тоног төхөөрөмжийн хийц “лабораторт 2019 онд “Бороожуулах хошууны борооны эрчим, усны жигд тархалт тодорхойлох төхөөрөмж”- ийг ашиглан туршилтыг хийж гүйцэтгэв. Нам даралтат бороожуулах хошууны борооны эрчмийг тодорхойлж, үр дүнг математик статистикийн аргаар боловсруулахад бороожуулах хошуугаар өгч буй усны хамгийн их хэмжээ 1.727 мм/мин нь даралт хамгийн их 30 PSI, шилжих хурд хамгийн бага 1м/мин үед байгаа бол хамгийн бага хэмжээ 0.313 мм/мин нь даралт тохируулагч 20 PSI утга дээр, шилжих хурд хамгийн их буюу 3 м/мин байв. Түлхүүр үг: Даралт тохируулагч, бороожуулах хошууны жигд тархалт, нам даралтат бороожуулах хошуу

V-SHAPED HOLES FOR FULL COVERAGE FILM COOLING OF A HIGH-PRESSURE NOZZLE GUIDE VANE

This paper describes an experimental activity carried out to investigate the potential of V-shaped holes for film cooling a high-pressure nozzle guide vane. The newly designed V-shaped scheme was compared with a standard laidback fan-shaped holes. The influence of showerhead cooling was also assessed. Different injection conditions were examined under the same cascade operating condition using CO2 as coolant. The quality of holes geometry and their discharging behavior was first characterized. Then dual luminophore Pressure Sensitive Paint (PSP) was used for measuring the adiabatic film cooling effectiveness all over the vane surface. Results of the current work showed that using a V-shaped hole configuration would give nearly the same surface protection as standard shaped holes with a reduced number of holes and, thus, at lower coolant flow consumption.

Comparison of Type-1 and Type-2 Fuzzy Systems for Mineralization of Bioprinted Bone

ABSTRACTBioprinting is an emerging tissue engineering method used to generate cell-laden scaffolds with high spatial resolution. Bioprinting parameters, such as pressure, nozzle size, and speed, have a large influence on the quality of the bioprinted construct. Moreover, cell suspension density, cell culture period, and other critical biological parameters directly impact the biological function of the final product. Therefore, an approximation model that can be used to find the values of bioprinting parameters that will result in optimal bioprinted constructs is highly desired. Here, we propose type-1 and type-2 fuzzy systems to handle the uncertainty and imprecision in optimizing the input values. Specifically, we focus on the biological parameters, such as culture period, that can be used to maximize the output value (mineralization volume). To achieve a more accurate approximation, we have compared a type-2 fuzzy system with a type-1 fuzzy system using two levels of uncertainty. We hypothesized that type-2 fuzzy systems may be preferred in biological systems, due to the inherent vagueness and imprecision of the input data. Here, our results demonstrate that the type-2 fuzzy system with a high uncertainty boundary (30%) is superior to type-1 and type-2 with low uncertainty boundary fuzzy systems in the overall output approximation error for bone bioprinting inputs.

Manufacturing process design of high-pressure graphite-blasting for mechanical production of turbostratic graphene

In this paper a manufacturing process is introduced to treat the bulk surfaces of surfaces via graphite powder blasting to directly produce an adherent layer of graphene. Subsequently, the study aims to correlate optical, thermal and electrochemical modifications with treatment parameters such as blasting pressure, nozzle distance and number of passes. After the treatment, the target surface has enhanced spectral, thermal and electrochemical properties because of the graphene’s turbostratic nature to adhesion to its surface. The thermal stability performance showed a consistent 5% increase relative to a bare aluminum substrate. A two-fold increase in corrosion resistance is seen in the sample compared to bare aluminum while diffuse absorbance values enhancement is around three-fold. This proposed manufacturing method provides straightforward and effective treatment at various degrees of automation. Since the deposited graphene substrate can cover a large area, it can be applied as a final layer on thermal collectors, PV panels and for other applications. It is possible to adopt this process to other well-established treatment plants without requiring high investments in the overhead expenses.

A Revisit of Rainfall Simulator as a Potential Tool for Hydrological Research

Different means of hydrological data collection have developed and used. However, they are constraint in one way or other. This paper therefore revisited the rainfall simulator as potential tool for hydrological research. The research disclosed that there are three different types of rainfall simulators; drop former simulator, pressure nozzle simulator and hybrid simulator. It can further be classified as indoor model and outdoor. The research also showed that precipitation is the driving force in hydrological studies. Consequently, in the design of rainfall simulator, the following should be taken into consideration: nozzle spacing, pump size, nozzle size, nozzle type, nozzle spacing, plot size and pressure. Meanwhile, intensity, distribution uniformity, kinetic energy, rainfall drop size and rainfall terminal velocity should be noted in its evaluation. Factoring-in the aforementioned design considerations, data collection is made easy without necessarily waiting for the natural rainfall. Since the rainfall can be controlled, the erratic and unpredictable changeability of natural rainfall is eliminated. Emanating from the findings, pressurized rainfall simulator produces rainfall characteristics similar to natural rainfall, which is therefore recommended for laboratory use if natural rainfall-like characteristics is the main target.

Modeling of the Production of Lipid Microparticles Using PGSS® Technique

Solid lipid microparticles (SLMPs) are attractive carriers as delivery systems as they are stable, easy to manufacture and can provide controlled release of bioactive agents and increase their efficacy and/or safety. Particles from Gas-Saturated Solutions (PGSS®) technique is a solvent-free technology to produce SLMPs, which involves the use of supercritical CO2 (scCO2) at mild pressures and temperatures for the melting of lipids and atomization into particles. The determination of the key processing variables is crucial in PGSS® technique to obtain reliable and reproducible microparticles, therefore the modelling of SLMPs production process and variables control are of great interest to obtain quality therapeutic systems. In this work, the melting point depression of a commercial lipid (glyceryl monostearate, GMS) under compressed CO2 was studied using view cell experiments. Based on an unconstrained D-optimal design for three variables (nozzle diameter, temperature and pressure), SLMPs were produced using the PGSS® technique. The yield of production was registered and the particles characterized in terms of particle size distribution. Variable modeling was carried out using artificial neural networks and fuzzy logic integrated into neurofuzzy software. Modeling results highlight the main effect of temperature to tune the mean diameter SLMPs, whereas the pressure-nozzle diameter interaction is the main responsible in the SLMPs size distribution and in the PGSS® production yield.