An assessment of strategies for the development of solid-state adsorbents for vehicular hydrogen storage

Allendorf, Mark D.,Hulvey, Zeric,Gennett, Thomas,Ahmed, Alauddin,Autrey, Tom,Camp, Jeffrey,Seon Cho, Eun,Furukawa, Hiroyasu,Haranczyk, Maciej,Head-Gordon, Martin,Jeong, Sohee,Karkamkar, Abhi,Liu, Di-J The Royal Society of Chemistry 2018 ENERGY AND ENVIRONMENTAL SCIENCE Vol.11 No.10

<P>Nanoporous adsorbents are a diverse category of solid-state materials that hold considerable promise for vehicular hydrogen storage. Although impressive storage capacities have been demonstrated for several materials, particularly at cryogenic temperatures, materials meeting all of the targets established by the U.S. Department of Energy have yet to be identified. In this Perspective, we provide an overview of the major known and proposed strategies for hydrogen adsorbents, with the aim of guiding ongoing research as well as future new storage concepts. The discussion of each strategy includes current relevant literature, strengths and weaknesses, and outstanding challenges that preclude implementation. We consider in particular metal-organic frameworks (MOFs), including surface area/volume tailoring, open metal sites, and the binding of multiple H2 molecules to a single metal site. Two related classes of porous framework materials, covalent organic frameworks (COFs) and porous aromatic frameworks (PAFs), are also discussed, as are graphene and graphene oxide and doped porous carbons. We additionally introduce criteria for evaluating the merits of a particular materials design strategy. Computation has become an important tool in the discovery of new storage materials, and a brief introduction to the benefits and limitations of computational predictions of H2 physisorption is therefore presented. Finally, considerations for the synthesis and characterization of hydrogen storage adsorbents are discussed.</P>

ONLINE SHOPPING CART ABANDONMENT - CONSUMER MOTIVES AND EFFECTIVE COUNTERMEASURES

Julian F Allendorf,Mirja Kroschke,Manfred Krafft 글로벌지식마케팅경영학회 2018 Global Marketing Conference Vol.2018 No.07

Shopping cart abandonment of the online shopping process is a major challenge for firms. It describes the phenomenon that a potential customer starts a check out process for an online order but drops out of the process before completing the purchase. On average, 650 out of 1,000 customers do not convert (Baymard Institute 2017), which highlights the managerial relevance and impact of this phenomenon for online firms. Since shopping cart abandonment directly affects an online firm’s sales and revenue, researchers and practitioners likewise are interested in understanding why people leave a website without completing the shopping process and, more importantly, how to reduce online shopping cart abandonment. However, to date, research on these questions is scarce (e.g., Kukar-Kinney and Close 2010) and firms lack guidance how to deal with online shopping cart abandonment. The goal of this study is to investigate effective countermeasures that firms can use to reduce and prevent the likelihood of abandonment and thereby to increase the likelihood of a conversion. We conducted a field experiment in cooperation with a German accessories online retailer over three weeks (n = 8,467 shopping carts) and tested the effectiveness of a reminder pop-up window with a 10% discount vs. a reminder pop-up window without a discount vs. a control group. All online store visitors within the period were randomly assigned to one of three groups once they have put an item in the shopping cart. The pop-up windows appeared once they were about to click on the exit button. Our results indicate that a reminder pop-up window with a 10% discount significantly increases the conversion rate on the website compared to the control group, leading to an increase in revenue of approximately € 5,000. In contrast, a reminder pop up window a discount does not seem to reduce shopping cart abandonment. Further, we will investigate how this campaign affects the retailer’s overall profitability. In addition, using a laboratory experiment (n = 1,041) we replicated and extended our insights on effective countermeasures for shopping cart abandonment. People seem to be more likely to convert when there is a guest checkout option available. In sum, our research has important implications for researchers and online firms how to deal with online shopping cart abandonment.

Nanostructured Metal Hydrides for Hydrogen Storage

Schneemann, Andreas,White, James L.,Kang, ShinYoung,Jeong, Sohee,Wan, Liwen F.,Cho, Eun Seon,Heo, Tae Wook,Prendergast, David,Urban, Jeffrey J.,Wood, Brandon C.,Allendorf, Mark D.,Stavila, Vitalie American Chemical Society 2018 Chemical reviews Vol.118 No.22

<P>Knowledge and foundational understanding of phenomena associated with the behavior of materials at the nanoscale is one of the key scientific challenges toward a sustainable energy future. Size reduction from bulk to the nanoscale leads to a variety of exciting and anomalous phenomena due to enhanced surface-to-volume ratio, reduced transport length, and tunable nanointerfaces. Nanostructured metal hydrides are an important class of materials with significant potential for energy storage applications. Hydrogen storage in nanoscale metal hydrides has been recognized as a potentially transformative technology, and the field is now growing steadily due to the ability to tune the material properties more independently and drastically compared to those of their bulk counterparts. The numerous advantages of nanostructured metal hydrides compared to bulk include improved reversibility, altered heats of hydrogen absorption/desorption, nanointerfacial reaction pathways with faster rates, and new surface states capable of activating chemical bonds. This review aims to summarize the progress to date in the area of nanostructured metal hydrides and intends to understand and explain the underpinnings of the innovative concepts and strategies developed over the past decade to tune the thermodynamics and kinetics of hydrogen storage reactions. These recent achievements have the potential to propel further the prospects of tuning the hydride properties at nanoscale, with several promising directions and strategies that could lead to the next generation of solid-state materials for hydrogen storage applications.</P> [FIG OMISSION]</BR>

The Role of Endoscopic Ultrasound-Guided Ki67 in the Management of Non-Functioning Pancreatic Neuroendocrine Tumors

YongYan Cui,Lauren G. Khanna,Anjali Saqi,John P. Crapanzano,James M. Mitchell,Amrita Sethi,Tamas A. Gonda,Michael D. Kluger,Beth A. Schrope,John Allendorf,John A. Chabot,John M. Poneros 대한소화기내시경학회 2020 Clinical Endoscopy Vol.53 No.2

Background/Aims: The management of small, incidentally discovered nonfunctioning pancreatic neuroendocrine tumors (NF-PNETs)has been a matter of debate. Endoscopic ultrasound with fine-needle aspiration (EUS-FNA) is a tool used to identify and risk-stratifyPNETs. This study investigates the concordance rate of Ki67 grading between EUS-FNA and surgical pathology specimens in NF-PNETs and whether certain NF-PNET characteristics are associated with disease recurrence and disease-related death. Methods: We retrospectively reviewed the clinical history, imaging, endoscopic findings, and pathology records of 37 cases of NF-PNETs that underwent pre-operative EUS-FNA and surgical resection at a single academic medical center. Results: There was 73% concordance between Ki67 obtained from EUS-FNA cytology and surgical pathology specimens; concordancewas the highest for low- and high-grade NF-PNETs. High-grade Ki67 NF-PNETs based on cytology (p=0.028) and histology (p=0.028)were associated with disease recurrence and disease-related death. Additionally, tumors with high-grade mitotic rate (p=0.005), tumorsize >22.5 mm (p=0.104), and lymphovascular invasion (p=0.103) were more likely to have poor prognosis. Conclusions: NF-PNETs with high-grade Ki67 on EUS-FNA have poor prognosis despite surgical resection. NF-PNETs withintermediate-grade Ki67 on EUS-FNA should be strongly considered for surgical resection. NF-PNETs with low-grade Ki67 on EUS-FNA can be monitored without surgical intervention, up to tumor size 20 mm.