Research Progress of Bonding Agents and Their Performance Evaluation Methods

Bonding agents are an important type of additive that are used to increase the interfacial interaction in propellants. A suitable bonding agent can prevent the dewetting between the oxidant and binder, and thus effectively improve the mechanical properties of the propellant. In the current paper, the bonding mechanisms and research progress of different types of bonding agents such as alcohol amine bonding agents, borate ester bonding agents, aziridine bonding agents, hydantoin bonding agents, neutral polymer bonding agents, and so on, are reviewed and discussed. The evaluation methods of their bonding performances including molecular dynamic simulation, contact angle method, in situ loading SEM, characterization analysis, and mechanical analysis are summarized to provide design ideas and reference for future studies.

Intelligent Reading Recognition Method of Pointer Meter Based on Deep Learning in Real Environment

The accurate reading of pointer meter is a crucial task in complex environments such as substations, military and aerospace. The current recognition algorithm is mainly used to identify the same type and non-tilt meter, which has limited application in real environment. This paper proposes a novel end-to-end intelligent reading method of pointer meter based on deep learning, which locates the meter and extracts the pointer simultaneously without any prior information. Especially, the pointer is directly and precisely extracted using the designed semi-pointer detection method without any handcrafted features designed in advance, which avoids the accumulated error caused by preprocessing. Based on the extracted panel object, including semi-pointer, panel center and scale characters, the indicated value of the pointer is obtained by a local angle method, which can achieve better performance than the traditional angle method by referring to the neighboring scale lines of the pointer. Experimental results demonstrate that the method is faster and more effective than some common methods. It is worth noting that this study has the advantage of being able to recognize pointer meters in complex environments such as tilt, rotation, blur and illumination. It is acceptable for the actual application requirements in real environment with a recognition accuracy of 99.20% and the average reference error of 0.34%.

Contact angle of modified fibrovascular bundle of salacca (Salacca sumatrana Becc.) frond by NaOH+Na2SO3 combination

The fibrovascular bundle (FVB) of the salacca frond is one of the potential raw materials in the development of bio-composite technology. The purpose of this study was to investigate the wettability of FVB using the contact angle method after the alkali modification treatment. The method of this research was to use FVB frond of Salacca sumatrana Becc. which was treated with alkaline modification of the combination of NaOH+Na2SO3 at various concentrations. The results showed that the combination of NaOH 1M+Na2SO3 0.4 M had the smallest contact angle, which means that the FVB has a good wettability value compared to the control treatment. Based on the results, it can be concluded that the modification of NaOH+Na2SO3 can increase the wettability of FVB.

EYES CANNOT SEE WHAT THE BRAIN DOES NOT KNOW

Background: Intraocular foreign body (IOFB) is a common ocular trauma and is a leading cause of visual impairment. Majority of the cases reported the occurrence at the workplace and usually related to activities involving metallic objects. Hammering, drilling, explosion and usage of machining tools are among the causes of IOFB. Foreign body in the angle are frequently missed as it is not visualised directly during a routine examination. Thus, a thorough examination which includes gonioscopy and imaging must be done in all penetrating and full thickness cornea laceration cases. Purpose: We report a case of self-sealed full thickness cornea laceration with presence of metal foreign body in the angle. Method: Case Report Result: A 19 year-old boy, presented with right eye discomfort following trauma 1 week prior to presentation. Examination revealed a self-sealed full thickness cornea laceration at 1-2 o’clock with a foreign body found seated on the angle from gonioscopy. A foreign body consist of metal had successfully removed surgically with the facilitation of intraocular magnet. Conclusion: All self-sealed penetrating injury to the eye required a high index of suspicious of intraocular foreign body. An imaging and complete examination with dilated fundus examination and gonioscopy will be helpful to identify the location of foreign body. Hence, definitive treatment will prevent long term complication related to intraocular foreign body.

Characteristics of Shale Wettability by Contact Angle and Its Influencing Factors: A Case Study in Songliao

Wettability is a significant factor in the exploration and development of shale oil. Currently, shale wettability has yet to reach a unified understanding. The contact angle is widely used in the study of shale wettability. However, the pre-treatment of the shale profoundly affects the contact angle. In this paper, the contact angle errors introduced by the pre-treatment of samples are discussed. Shale wettability is influenced by many factors, and there is not yet a systematic study of its influencing factors. Based on the above issues, the shale of the northern Songliao Basin was taken as the subject. The wettability of the different lithofacies is characterized by an improved contact angle method. The compositional characteristics of the shales and oil in the study area were analyzed. Fresh minerals, a single component of oil, and different temperature/pressure conditions were set up to investigate the influencing factors of shale wettability. The studies show that Organic matter abundance and thermal maturity have a positive correlation with oil-wet. Siliceous minerals are positively correlated with water-wet. Carbonate and clay minerals are negatively correlated with water-wet. The mineralogical composition of the shale, the composition of the oil, the characteristics of the aqueous media, the asphaltene deposits on the surface, temperature, and pressure all impact wettability. The affinity of minerals for hydrocarbons is iron minerals > carbonate minerals > clay minerals > siliceous minerals. Minerals are more hydrophilic at low salinity conditions. The deposition of non-hydrocarbons and asphaltenes renders the surface oleophilic. Increasing temperatures will reduce the hydrophilicity of the “oil-water-rock”.

Formation and Optimization of Electrical Discharge Coatings Using Conventional Electrodes

An emerging topic is electrical discharge (ED) coating with its application on complex shapes and cavities to repair components or act as functional coatings. Because it is a variant process of an electric discharge machine (EDM) with the ability to coat on electrically conductive substrates, there is a possibility that next-generation electrical discharge machining components may exploit the attachment phenomenon to enhance recast layer properties. Previously, researchers have obtained ED coating by mixing the powder in a dielectric medium and/or by using powder metallurgy electrodes. In this work, primarily, an insight in the formation of ED coating on-die sinks electrical discharge machine, using conventional electrode materials viz., bronze on titanium alloy (Ti-6Al-4V) is made. The bronze electrode on the titanium substrate obtained a crack-free copper coating of ~20 microns thickness. In order to perform the experiments, three combinations were made using five parameters: current (Amps), ton (µs), Toff (µs), duty cycle (%), and flushing pressure as constant (bar). After obtaining the coating, a combination of input parameters was selected by optimizing the output performance parameters, viz., the electrical discharge deposition rate, coating thickness, micro-cracks, and elemental coating composition. Secondarily, different optimization techniques viz., grey relational analysis, the technique for order of preferences by similarity to ideal solution, −nD angle method and information divergence method were implemented to find out the suitable combination of parameters where the latter two methods were introduced for the first time in this area of EDM optimization. A study was conducted to check whether the latter two methods are optimization techniques or multi-criteria decision-making techniques. The optimization of existing reactor types and the development of new reactors in wastewater treatment through EDC, by which energy could be saved by replacing the conventional techniques.