Highly-tunable formation of nitrogen-vacancy centers via ion implantation

We demonstrate highly-tunable formation of nitrogen-vacancy (NV) centers using 20 keV 15N+ ion implantation through arrays of high-resolution apertures fabricated with electron beam lithography. By varying the aperture diameters from 80 to 240 nm, as well as the average ion fluences from 5 x 10^10 to 2 x 10^11 ions/cm^2, we can control the number of ions per aperture. We analyze the photoluminescence on multiple sites with different implantation parameters and obtain ion-to-NV conversion yields of 6 to 7%, consistent across all ion fluences. The implanted NV centers have spin dephasing times T2* ~ 3 microseconds, comparable to naturally occurring NV centers in high purity diamond with natural abundance 13C. With this technique, we can deterministically control the population distribution of NV centers in each aperture, allowing for the study of single or coupled NV centers and their integration into photonic structures.Comment: Related papers at http://pettagroup.princeton.ed

Importance of understanding variable and transient energy demand in large multi-product industrial plants for process integration

There have been some news releases claiming that Professor Henle in Germany has found the chemical identity of UMF, and that in future chemical analysis will be used instead of assays of antibacterial activity to indicate the level of UMF in manuka honey. Both of these claims are misleading. Because the level of active substance in manuka honey is an unreliable indication of the level of antibacterial activity and can be very misleading, it is hard to see any commercial advantage for it to be used to indicate antibacterial activity other than if someone wanted to fool the consumer into thinking that the higher numbers are giving them a level of antibacterial activity that is far higher than they are really getting

A derivative method for minimising total cost in heat exchanger networks through optimal area allocation

This paper presents a novel Cost Derivative Method (CDM) for finding the optimal area allocation for a defined Heat Exchanger Network (HEN) structure and stream data, without any stream splits to achieve minimum total cost. Using the Pinch Design Method (PDM) to determine the HEN structure, the approach attempts to add, remove and shift area to exchangers where economic benefits are returned. From the derivation of the method, it is found that the slope of the ε-NTU relationship for the specific heat exchanger type, in combination with the difference in exchanger inlet temperatures and the overall heat transfer coefficient, are critical to calculating the extra overall duty each incremental area element returns. The approach is able to account for differences in film coefficients, heat exchanger types, flow arrangements, exchanger cost functions, and utility pricing. Incorporated into the method is the newly defined “utility cost savings flow-on” factor, θ, which evaluates downstream effects on utility use and cost that are caused by changing the area of one exchanger. To illustrate the method, the CDM is applied to the distillation example of Gundersen (2000). After applying the new CDM, the total annual cost was reduced by 7.1 % mainly due to 24 % less HEN area for similar heat recovery. Area reduction resulted from one exchanger having a minimum approach temperature (ΔTmin) of 7.7 °C while the other recovery exchangers had larger ΔTmin values. The optimum ΔTmin for the PDM was 12.5 °C. The CDM solution was found to give a comparable minimum total area and cost to two recently published programming HEN synthesis solutions for the same problem without requiring the increased network complexity through multiple stream splits

Brane world models need low string scale

Models with large extra dimensions offer the possibility of the Planck scale being of order the electroweak scale, thus alleviating the gauge hierarchy problem. We show that these models suffer from a breakdown of unitarity at around three quarters of the low effective Planck scale. An obvious candidate to fix the unitarity problem is string theory. We therefore argue that it is necessary for the string scale to appear below the effective Planck scale and that the first signature of such models would be string resonances. We further translate experimental bounds on the string scale into bounds on the effective Planck scale

Building theory on the negotiation capability of the firm: evidence from Ryanair

Purpose: In an attempt to build upon existing theory, this paper investigates the potentially reciprocal relationship between negotiation and strategy, and strives to contribute towards a better understanding of the ways in which organizations negotiate. Design/methodology/approach: Built upon the integration of two different bodies of literature, negotiation and strategy, and on the analysis of the case of Ryanair, this paper argues for an integrated approach to negotiation and organizational capabilities. Findings: The case study allows for a clearer understanding of how negotiation capability can play a significant role in supporting the creation and sustainment of competitive advantage, even under unfavorable industry settings. Originality/value: The paper contributes to theoretical development by offering new and insightful explanations of firms’ behavior, moving beyond the classic interpretation of industry dynamics, such as bargaining power. This study has implications for both practice and research, as it offers a better and more holistic understanding of the strategy making process and the foundations of its success

Performance of Sorghum Hybrids in Relation to Sources of Resistance to Biotype C of the Greenbug

This paper presents results of research on the agronomic performance of sorghum [Sorghum bicolor (L.) Moench.] hybrids derived from several germplasm sources that possess resistance to biotype C of the greenbug [Schizaphis graminum (Rondani)]. Significant differences among hybrids with resistance from different sources were evident for grain yield, seeds/head, heads/plant, days to midbloom, and plant height. SA7536-1 seemed superior to KS30, IS809, and PI264453 resistance sources in potential for producing high-yielding hybrids with resistance to biotype C. Greater numbers of seeds/head was the component largely responsible for the yield advantage of the SA7536-1 hybrids

COVID has changed students’ needs and expectations. How do universities respond?

Flexibility is often understood as student preferences for modes of learning. Some students see benefits in fully online learning and may decide to continue in that mode. The majority, though, have expressed a strong desire to return to campus. But they want to retain the flexibility of online learning. This conversation piece explores how universities move forward with teaching post-pandemic

Developing interventions to change recycling behaviors: A case study of applying behavioral science

The Theoretical Domains Framework (TDF) and the Behavior Change Wheel (BCW) are frameworks that can be used to develop recycling interventions. The aim of this study was to demonstrate the utility of these frameworks for developing recycling interventions. 20 semistructured interviews with university building users were analyzed using the TDF and BCW. Environmental context and resources, beliefs about consequences, knowledge, and intention were identified as the key theoretical domains influencing recycling behaviors. The BCW was used to develop recommendations for intervention. This research is the first case study to demonstrate how the TDF and the BCW can be used to develop recycling interventions