Preparation and Ballistic Performance of a Multi-Layer Armor System Composed of Kevlar/Polyurea Composites and Shear Thickening Fluid (STF)-Filled Paper Honeycomb Panels

In this study, the ballistic performance of armors composed of a polyurea elastomer/Kevlar fabric composite and a shear thickening fluid (STF) structure was investigated. The polyurea used was a reaction product of aromatic diphenylmethane isocyanate (A agent) and amine-terminated polyether resin (B agent). The A and B agents were diluted, mixed and brushed onto Kevlar fabric. After the reaction of A and B agents was complete, the polyurea/Kevlar composite was formed. STF structure was prepared through pouring the STF into a honeycomb paper panel. The ballistic tests were conducted with reference to NIJ 0101.06 Ballistic Test Specification Class II and Class IIIA, using 9 mm FMJ and 44 magnum bullets. The ballistic test results reveal that polyurea/Kevlar fabric composites offer better impact resistance than conventional Kevlar fabrics and a 2 mm STF structure could replace approximately 10 layers of Kevlar in a ballistic resistant layer. Our results also showed that a high-strength composite laminate using the best polyurea/Kevlar plates combined with the STF structure was more than 17% lighter and thinner than the conventional Kevlar laminate, indicating that the high-strength protective material developed in this study is superior to the traditional protective materials.

Device and Method for Measuring Volume in Receptacles for Storing Wine

This study is on the design and method of a volume measuring device installed inside a box used to store liquids mainly wine. Current devices that store wine in boxes have inside these boxes, inner boxes regularly made of rigid cardboard and a sealed plastic receptacle, which has an outlet tap to serve the wine. The device is focused on being used in the new wine packaging in a cardboard box. The measuring device is placed at the bottom of the wine dispenser box and displays a measurement of the volume of the wine even in the box via a measurement tower. The wine storage box contains inside: the device located at the bottom of the box containing the wine (i.e., the liquid), and the plastic container containing the wine above our measuring device. The measuring device will feel the weight of the current wine content in the plastic container and will automatically move a signal indicating the level of the liquid even in the plastic container. The measurement will be visible from the outside of the box by the consumer, the device is included by a receptacle or sealed bag connected to the measurement tower. The weight measurement receptacle is sealed and made of a material with a leak-resistant layer, and which is usually irregularly oval and is filled with at least one form of gas or air and where the packing layer is shaped to fill the bottom of the container and it is placed under the bag for storage and shipping. As the pressure of the liquid weight changes, the receptacle reacts by moving a measuring marker that reflects such changes, thus measuring the current volume of the liquid in the shipping box. There are numerous patents for measuring liquids, particularly for wine, and then we present several of these patents that are the most relevant to our case

Thermophysical characteristics of the formed layer of foam coke when protecting fabric from fire by a formulation based on modified phosphorus-ammonium compounds

This paper reports the analysis of flame retardants for fabrics that has established that the meagerness of the data that explain and describe the process of fire protection, as well as the neglect of elastic coatings, leads to the combustion of structures made from fabrics under the influence of flame. The development of reliable methods to study the fire protection conditions for fabrics leads to the design of new types of fireproof materials. Therefore, it becomes necessary to define the conditions for the formation of a barrier for burning and flame propagation by a piece of fabric and for establishing a mechanism that would inhibit a temperature transfer to the material. To address this issue, an estimation-experimental method has been devised for determining thermal conductivity when using a fire protection agent as a coating, which makes it possible to assess the thermal conductivity coefficient under the effect of high temperature. Based on the experimental data and theoretical dependences, the coefficient of thermal conductivity for the fire-resistant layer of foam coke was calculated, 0.034 W/(m∙K), which, accordingly, ensures the heat resistance of the fabric. The study results have proven that the process of the thermal insulation of fabric involves the formation of soot-like products at the surface of the sample. The inhibition of the process of heat transfer to the material treated with a composition based on modified phosphorus-ammonium compounds is characterized by the formation of a heat-protective layer of coke at the surface of the fabric. The maximum possible penetration of temperature through the thickness of the coating has been estimated. At the surface of the sample, a temperature was generated that significantly exceeds the ignition temperature of the fabric, and, at the non-heated surface, does not exceed 150 °C. Thus, there is reason to assert the possibility of targeted adjustment of fire protection processes in the fabric by applying coatings that can form a protective layer on the surface of the material, which inhibits the rate of heat transfer

Study of the influence of the housing on the cooling efficiency of the piezoceramic electroacoustic Langevin-type transducer

The object of research is thermal processes in Langevin-type piezoceramic electroacoustic transducers (PET), taking into account the housing. The piezoceramic electroacoustic transducers heat up during operation. Overheating of the converter leads to negative consequences, accompanied by a change in the parameters, characteristics of the device, as well as the failure of the converter. Or limitation on the duration and mode of operation, output power, current, amplitude and speed of oscillation of the converter. The paper investigates the effect of the housing on the temperature field of a Langevin-type PET by the finite element method, using modeling in SolidWorks. The results of temperature reduction of such cooling methods are shown: – filling the housing cavity with electrical insulating liquid, gas, a mixture of thermal paste; – use of holes in the housing; – changing the shape of the rear cover to have radiator side fins, vertical radiator fins, cylindrical radiator fins; – heat-resistant layer; – use of active air cooling at three different speeds. The most efficient 53 % and a uniform temperature field were found when filling with a mixture of thermal paste, but this solution is accompanied by additional experiments and a preparatory stage with the mixture. The cooling efficiency of 47 % was provided by active cooling – blowing with air, and this method requires additional equipment. Filling with insulating liquid gave a cooling efficiency of 27 % – an optimal result that does not require expensive investments. Slow blowing of the housing or adding only holes resulted in a decrease in the maximum heating temperature from 10 to 20 %, therefore, if the PET design allows the presence of holes, then it is necessary to rationally place them. Changing the shape of the back plate, heat-absorbing element, filling the housing with gas gave an efficiency decrease in the maximum temperature by 6–8 % compared to a closed housing with air. The research results make it possible to choose the optimal option for reducing the heating temperature of the Langevin-type PET to increase its efficiency and long-term trouble-free operation.

Static Electroplating of Iron Triad on Fastener Washers

Fasteners are commonly used in construction industry for parts joining purpose. There are many types of construction fasteners such as stud, bolt, anchor, nut, screw, and washer. The major problem of the fastener made by carbon steel is the poor resistance to corrosion. Electroplating is a simple yet low-cost tool to give a strong corrosion protection coating layer on the carbon steel. This study was performed to investigate the effect of current and deposition time on the iron triad (cobalt-nickel-iron) electroplating on the fastener washer. The experiment was conducted at 50 °C, pH 1-3 and at different electroplating time (30 minutes to 90 minutes) and current (0.2 A to 0.5 A). Burnt-out surface coating was observed on the fastener washer when the current was more than 0.4 A. A field test was carried out for 60 days to observe the corrosion behavior and performance of the products. Scanning electron microscope (SEM) analysis showed that a thin protection layer with 5.64 µm was formed at 60 minutes of electroplating time and 0.4 A of current. The surface roughness of the fastener washer was increased by increasing the electroplating time and current. The hardness was also improved with higher current and electroplating time if compared to the original fastener washer. The result of this study confirmed that a strong adhesive corrosion resistant layer to the fastener washer was using the current of 0.4 A (77 mA/cm2) and the electroplating time of 60 minutes.