The surface effects on the critical dimensions of ferromagnetic nanoparticles have been studied. Iron nanoparticles with different mean diameter from 5.9 nm to 21.4 nm were prepared by thermal decomposition of iron pentacarbonyl in the presence of oleic acid/octyl ether. The heating response of these ferromagnetic nanoparticles suspended in water were measured experimentally during which the same amount of iron nanoparticles and di-ionized water were irradiated by an alternating magnetic field and the increase in temperature of the system was measured. The heating performance of the nanoparticles was described in terms of Specific Absorption Rate (SAR) which depends on the heating rate. The heating rate was calculated from the initial slope of the heating curve at an inflection point whereby there is minimum heat loss to the surrounding. Results were analyzed to find the critical diameters for the transition from single-domain to superparamagnetic regime and from single-domain to multi-domain regime. Also, the frequency and current dependence of SAR were studied. The maximum value of SAR was obtained when the applied frequency and current were at 175 kHz and 15 A, respectively. An equation for the critical radius for the transition from single-domain to multi-domain regime with low anisotropy was derived and numerically solved by using a program written in C++ and results were analyzed to find the effect of surface parameters on the critical diameter of nanoparticles. The SAR as a function of nanoparticle’s diameter shows two maxima which can be connected with the two critical dimensions. One is D C1 at 18 nm for the transition from single-domain to multi-domain configuration and the second is D C2 at 10 nm for the transition from single-domain to superparamagnetic regime. Comparison of these experimental results with the bond order-length-strength correlation theory was discussed.
Scepticism towards marketing activities is a common consumer cognition. Despite its widespread prevalence, no attempt has been made in the past to review and synthesise the extant literature on scepticism. This study presents a comprehensive review and analysis of consumer scepticism literature from various domains of marketing. The paper critically examines various definitions, operationalisations, typologies, and the theoretical foundation of consumer scepticism, and differentiates scepticism from related constructs of (dis)trust, dissonance, and ambivalence. It presents a synthesis of literature on the antecedents (individual, product, and claim-related factors) and consequences (for promotions, products, retailers, and firms) of consumer scepticism. A framework is proposed based on the synthesis. The framework can help researchers studying scepticism in a particular domain (like health-related claims) identify relevant variables from other domains (like environmental claims). Results of the review process reveal a lack of clarity on the dimensionality and the measurement of scepticism; a paucity of research on drivers and consequences of consumer scepticism; and the need for further investigation of the concept of situational scepticism.
Purpose This paper aims to examine the effect of three types of health-related claims (health, nutrition and ingredient) and product healthiness on situational skepticism toward the claims that appear on the front-of-package of food products. The effect of situational skepticism on the purchase intention of the product is further examined. Design/methodology/approach Two experimental studies were conducted with a 3 (health-related claims: health claim vs nutrition claim vs ingredient claim) × 2 (product healthiness: healthy vs unhealthy) between-subjects factorial design. Study 1 investigates the effects within a single product category (Biscuits) and Study 2 the effects across product categories (Salad and Pizza). Findings The results demonstrate that situational skepticism is the highest for health claims, followed by nutrition claims and the least for ingredient claims. In addition, situational skepticism is higher for claims appearing on unhealthy products vis-à-vis healthy ones. Finally, situational skepticism mediates the relationship between claim type, product healthiness and product purchase intention. Research limitations/implications This study contributes to the field of nutrition labeling by advancing research on information processing of nutrition labels through the lens of the persuasion knowledge model (Friestad and Wright, 1994). Specifically, this study contributes to a nuanced understanding of claim formats on how the language properties of the claim – its vagueness, specificity and verifiability – can affect consumer perception. This study finds that higher specificity, verifiability and lower vagueness of ingredient claims lead to lower skepticism and hence higher purchase intention. Practical implications Furthermore, this study incrementally contributes to the ongoing discussion about the claim–carrier combination by showing that health-related claims are better perceived on healthy compared to unhealthy products. Hence, managers should avoid health washing, as this can backfire and cause harm to the reputation of the firm. Social implications From a public policy point of view, this study makes a case for strong monitoring and regulations of ingredient claims, as consumers believe these claims easily and hence can be misled by false ingredient claims made by unethical marketers. Originality/value The scope of research on skepticism has largely been limited to examining a general individual tendency of being suspicious (i.e. dispositional skepticism) in health-related claims as well as other areas of marketing. In this research, the authors extend the scope by examining how specific types of claims (health vs nutrition vs ingredient) and product healthiness jointly impact consumer skepticism, i.e. situational skepticism.
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