Daniel J. Shanefield

Development of a binder formulation for fused deposition of ceramics

A new family of thermoplastic binders has been developed for usage in fused deposition of ceramics (FDC). Mixtures were formulated consisting of a base binder, tackifier, wax, and plasticizer. The resultant formulation was chosen based on mechanical, rheological, and thermal property requirements. A formulation consisting of 100 parts base binder (by weight), along with 20 parts tackifier, 15 parts wax, and five parts plasticizer exhibited an optimized compromise of mechanical, rheological, and thermal properties. This formulation was compounded with 55 vol. per cent lead zirconate titanate (PZT) powder, and extruded into filaments with a diameter of 1.75mm and a length of approximately 50 (+/‐10) cm. The resulting filaments were used to fabricate functional piezoelectric ceramic devices via FDC. The binder development process is described, along with the associated mechanical, rheological, and thermal property data.

Thermal decomposition behaviour of poly(propylene carbonate)

Abstract Thermal analysis techniques including thermal gravimetric analysis (TGA), differential thermal analysis (DTA), and TG-FTIR were employed to investigate the thermal decomposition behaviours of poly(propylene carbonate) as a neat polymer and in the presence of AlN powder. It was found that the decomposition of poly(propylene carbonate) followed a depolymerisation mechanism and left no detectable residues. The combustion reaction in air enhanced the decomposition of the PPC binder in air only slightly compared to acrylic and PVB binders. In the presence of AlN powder, the PPC binder left primarily “gas phase mediated char” on the powder surface.

Poly(Vinyl Butyral) Pyrolysis: Interactions with Plasticizer and Ain Ceramic Powder

TGA and FTIR were employed to investigate the effects of dibutyl phthalate and butyl benzyl phthalate on the thermal degradation behavior of PVB, a binder used commonly for tape casting. Butyl benzyl phthalate was found to enhance the crosslinking of the PVB binder when heated in a nitrogen atmosphere during binder pyrolysis, which retarded its thermal degradation. The interaction between AIN powder and PVB binder was also studied by using TGA, XPS and a special furnace for collecting residual carbon. Intrinsic char and gas phase mediated char were studied separately.

CHAPTER 24 – Digital Microprocessor ICs

his chapter discusses digital microprocessor integrated circuits (ICs). Analog electrical signals are still used for many purposes—such as local telephone calls, and for some types of fairly simple computers in automation, etc. However, relatively small but very powerful computers, and also some large supercomputers, now use digital microprocessors for their internal operations. The binary digital programs for these microprocessors consist of extremely long lists of binary (zero or one) numbers. This is called machine language. Groups of these numbers, somewhat summarized into a symbolic format, are called object code, and this is considered to be a sort of language, at a slightly higher level than the raw zeros and ones. The chapter also elaborates on different computer languages.

CHAPTER 21 – SCRs and Triacs

This chapter presents a new way of controlling high current through the use of Silicon–control rectifiers (SCR) and trigger diode in the same device. Relaxation oscillators such as power controllers and proportional controllers are discussed in the chapter. Power Controllers are used to control large amounts of power. The proportional controllers are used to decrease or increase the amount of heat in devices as the temperature gets closer to a desired value. These are also referred to as Proportional–Integral–Derivative (PID) controllers.

CHAPTER 7 – Soldering

This chapter explains the process of soldering in detail. It provides a method for making a good solder joint. The chapter illustrates good and bad solder contact angles with the help of a diagram.

CHAPTER 18 – FETs and Tubes

This chapter explains the difference between FETs and Vacuum Tubes. Modem electronics would not be practical without amplification because this allows a large number of operations to be performed in series, without any total loss of signal strength from various resistances. Instead of making a transistor that conducts across both PN junctions when it is turned on, a transistor can be made with just a single PN junction that participates in the action. One such device is illustrated in the chapter. Modem integrated circuits (ICs) have millions of transistors attached in parallel, and even if only a microamp of leakage current flowed through each one that was not being used, an ampere or so would still be drawn from the power supply or battery at all times. This would generate a lot of heat and also drain batteries too fast for portable devices to be practical. Therefore, almost all modem calculators, laptop computers, cellular phones, etc. use complementary MOS (CMOS) circuits whenever possible.

CHAPTER 8 – The Oscilloscope

This chapter discusses what oscilloscope is and what it does. Oscilloscope is a type of electronic test instrument that allows the observation of constantly varying signal voltages. Some of the experiments provided in the chapter touches on the basic oscilloscope, sine wave, the square wave, high input resistance and EMI, the twisted pair, balanced lines, shielding, X versus Y inputs, and the curve tracer.

CHAPTER 4 – Series Resistances, Part I: Bad Output Voltages

This chapter discusses the problem of bad output voltages. Several different analogies involving water behavior are used as aids in explaining electrical behavior. In a few cases, the result is not what one might ordinarily expect, without considerable analysis. A few experiments to measure resistance, current, and voltage are discussed in the chapter. Devices in parallel have the same voltage across them and the devices in series have the same current going through them. When current goes through a resistance, some of the driving voltage is decreased; however, that voltage is available to go somewhere else. A potentiometer, which is two resistors with a connection available between them, is also discussed in the chapter with the help of an experiment.

CHAPTER 3 – Resistances in Parallel

This chapter discusses standard RETMA values, color coding, and the methods of obtaining resistance. Resistance to the flow of electricity is greater when the wire or other conductor is very narrow, similar to the flow of water in a very narrow pipe. At higher temperatures, the atoms of the conductive material move around randomly and are therefore not in their usual positions within the material, which also slows the net forward motion to some degree. Also, the electrons tend to collide with each other, which cause them to deviate from a straight path. The heating effect is used in a special type of thermistor device, where temperature can be measured by noting the rise in resistance. The inexpensive resistors to be used in this course are mostly the carbon composition type, which are graphite plus clay with a plastic insulating coating around the outside. The insulating coating around the resistor is usually epoxy plastic. A water pump analog of two resistors in parallel and the electrical example are also discussed in the chapter.