Student-designed experiments in general chemistry using laboratory interfacing

We present a spreadsheet-assisted exercise using Microsoft Excel software for the determination of the universal gas constant, R, in 35,712 different units. This large number of units arises from a simple enumeration of possible pressure-volume unit combinations and energy unit combinations covering SI (metric), Imperial (British), and American units. In turn, various units for force and area used for defining pressure, and various units for force and distance used for defining energy are explored. This presentation serves as an excellent exercise for high school and undergraduate students to master the skill of dimensional analysis, unit conversions, and basic combinatorics in general chemistry and physical chemistry courses. Instructors can also use the described exercise of constructing conversion matrices to train students in how to efficiently use the Microsoft Excel spreadsheet program.

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Revisiting Glycerol Esterification with Acetic Acid over Amberlyst-35 via Statistically Designed Experiments: Overcoming Transport Limitations

10.26434/chemrxiv.7731305.v1 ◽

2019 ◽

Author(s):

Víctor Gabriel Baldovino Medrano ◽

Karen V. Caballero ◽

Hernando Guerrero-Amaya

Keyword(s):

Acetic Acid ◽

Active Sites ◽

Batch Reactor ◽

Catalyst Particle ◽

Experimental Designs ◽

Particle Sizes ◽

Turnover Rates ◽

Designed Experiments ◽

Different Temperatures ◽

Glycerol Esterification

Turnover rates for glycerol esterification with acetic acid over Amberlyst-35 were measured under different temperatures, reactants and active sites concentrations, and catalyst particle sizes. Data were collected in a batch reactor. Experiments were done following a sequence of factorial experimental designs.

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Burn-in Failure Analysis of 0.5μm 1MB SRAM: Barrier Glue Layer Cracks and Tungsten Plug “Worm Holes”

ISTFA 1996: Conference Proceedings from the 22nd International Symposium for Testing and Failure Analysis ◽

10.31399/asm.cp.istfa1996p0159 ◽

1996 ◽

Author(s):

E. Widener ◽

S. Tatti ◽

P. Schani ◽

S. Crown ◽

B. Dunnigan ◽

...

Keyword(s):

Failure Analysis ◽

Product Quality ◽

Cmos Process ◽

Designed Experiments ◽

Root Cause ◽

Poly Silicon ◽

New Process ◽

Supply Current ◽

Electrical Analysis ◽

Current Characteristics

Abstract A new 0.5 um 1 Megabit SRAM which employed a double metal, triple poly CMOS process with Tungsten plug metal to poly /silicon contacts was introduced. During burn-in of this product, high currents, apparently due to electrical overstress, were experienced. Electrical analysis showed abnormal supply current characteristics at high voltages. Failure analysis identified the sites of the high currents of the bum-in rejects and discovered cracks in the glue layer prior to Tungsten deposition as the root cause of the failure. The glue layer cracks allowed a reaction with the poly/silicon, causing opens at the bottom of contacts. These floating nodes caused high currents and often latch-up during burn-in. Designed experiments in the wafer fab identified an improved glue layer process, which has been implemented. The new process shows improvement in burn in performance as well as outgoing product quality.

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