Water-Splitting Photoelectrolysis Reaction Rate via Microscopic Imaging of Evolved Oxygen Bubbles

Bubble formation and growth on a water-splitting semiconductor photoelectrode under illumination with above-bandgap radiation provide a direct measurement of the gas-evolving reaction rate. Optical microscopy was used to record the bubble growth on single-crystal strontium titanate immersed in basic aqueous electrolyte and illuminated with UV light at 351/364 nm from a focused argon laser. By analyzing the bubble size as a function of time, the water-splitting reaction rate was determined for varying light intensities and was compared to photocurrent measurements. Bubble nucleation was explored on an illuminated flat surface, as well as the subsequent light scattering and electrode shielding due to the bubble. This technique allows a quantitative examination of the actual gas evolution rate during photoelectrochemical water splitting, independent of current measurements

Do Loyalty Programs Really Enhance Behavioral Loyalty? An Empirical Analysis Accounting for Self-Selecting Members

One of the pressing issues in marketing is whether loyalty programs really enhance behavioral loyalty. Loyalty program members may have a much higher share-of-wallet at the firm with the loyalty program than non-members have, but this does not necessarily imply that loyalty programs are effective. Loyal customers may select themselves to become members in order to benefit from the program. Since this implies that program membership is endogenous, we estimate models for both the membership decision (using instrumental variables) and for the effect of membership on share-of-wallet, our measure of behavioral loyalty. We use panel data from a representative sample of Dutch households who report their loyalty program memberships for all seven loyalty programs in grocery retailing as well as their expenditures at each of the 20 major supermarket chains. We find a small positive yet significant effect of loyalty program membership on share-of-wallet. This effect is seven times smaller than is suggested by a naïve model that ignores the endogeneity of program membership. The predictive validity of the proposed model is much better than for the naïve model. Our results show that creating loyalty program membership is a crucial step to enhance share-of-wallet, and we provide guidelines how to achieve this.Attraction models;Endogeneity;Grocery retailing;Loyalty programs;Tobit-II model

Do Loyalty Programs Enhance Behavioral Loyalty: An Empirical Analysis Accounting for Program Design and Competitive Effects

This paper studies the effects of loyalty programs on share-of-wallet using market-wide household panel data on supermarket purchases.We find that loyalty programs relate positively to share-of-wallet, but the programs differ in effectiveness and some are ineffective.Both a saving component and a multi-vendor structure enhance the effectiveness of a loyalty program, but high discounts do not lead to higher share-of-wallets.Further, if households have multiple loyalty cards, the effectiveness of a specific loyalty program is much smaller.The positive loyalty program effects on share-of-wallet entail substantial additional customer revenues.However, given the high number of loyalty programs already available in the market, our model predicts that a new loyalty program introduction will only lead to small effects on share-of-wallet.loyalty;marketing;retailing

Do Loyalty Programs Enhance Behavioral Loyalty:An Empirical Analysis Accounting for Program Design and Competitive Effects

This paper studies the effects of loyalty programs on share-of-wallet using market-wide household panel data on supermarket purchases.We find that loyalty programs relate positively to share-of-wallet, but the programs differ in effectiveness and some are ineffective.Both a saving component and a multi-vendor structure enhance the effectiveness of a loyalty program, but high discounts do not lead to higher share-of-wallets.Further, if households have multiple loyalty cards, the effectiveness of a specific loyalty program is much smaller.The positive loyalty program effects on share-of-wallet entail substantial additional customer revenues.However, given the high number of loyalty programs already available in the market, our model predicts that a new loyalty program introduction will only lead to small effects on share-of-wallet.

Do Loyalty Programs Enhance Behavioral Loyalty:An Empirical Analysis Accounting for Program Design and Competitive Effects

This paper studies the effects of loyalty programs on share-of-wallet using market-wide household panel data on supermarket purchases.We find that loyalty programs relate positively to share-of-wallet, but the programs differ in effectiveness and some are ineffective.Both a saving component and a multi-vendor structure enhance the effectiveness of a loyalty program, but high discounts do not lead to higher share-of-wallets.Further, if households have multiple loyalty cards, the effectiveness of a specific loyalty program is much smaller.The positive loyalty program effects on share-of-wallet entail substantial additional customer revenues.However, given the high number of loyalty programs already available in the market, our model predicts that a new loyalty program introduction will only lead to small effects on share-of-wallet

Comparison of lipid character of sediments from the Great Lakes and the Northwestern Atlantic

Geolipid compositions of surficial sediments from Lake Michigan, Lake Huron, and from three locations in the Northwestern Atlantic were determined to compare source inputs and alteration processes in different sedimentary environments. Fatty acids, sterols, fatty alcohols, and alkanes were examined in both unbound and bound extracts of these samples. Significant amounts of long chain fatty acids, alcohols, and hydrocarbons are present in the deep ocean station, yet this location contains a proportionally larger amount of short chain geolipids than do marine stations closer to shore. Larger proportions of long chain lipids present in the Lake Michigan, Lake Huron, and Gulf of Maine samples relative to the open ocean samples reflect larger inputs of land-derived lipids to sediments closer to terrigenous sources. Marine samples contain a more complex mixture of sterols than is found in lake sediments, suggesting that sterol inputs and alteration processes in the marine environment are more complex than in lacustrine settings. Ratios of 16:1/16:0 and 18:1/18:0 fatty acids decrease with increasing distance from land, which suggests that fatty acid degradation before and during deposition becomes more extensive in the open deeper ocean stations.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24970/1/0000397.pd

Organic geochemistry of suspended and settling particulate matter in Lake Michigan

Organic matter contained in particulate matter in Lake Michigan waters and sediments has been characterized by C/N ratios and by distributions of biomarker fatty acids, alkanols, sterols, and aliphatic hydrocarbons. Differences in organic constituents of particulate matter from various depths and distances from shore indicate a complex interaction of production, transformation, and destruction of the organic matter contained in sinking particles. Near-surface material contains important contributions of landderived organic matter, presumably of eolian input. Midwater particles have predominantly aquatic organic material of algal origin. At the sediment-water interface, selective suspension of the finer fractions of surficial sediments enriches bottom nepheloid layers with these sediment size classes. As a result, near-bottom particulate matter has an aquatic biomarker character. Organic matter associated with sinking particles undergoes substantial degradation during passage to the bottom of Lake Michigan, and aquatic components are selectively destroyed relative to terrigenous components.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24895/1/0000322.pd