Access to this document was granted through an Emerald subscription provided by CALIFORNIA STATE UNIVERSITY FRESNO For Authors:If you would like to write for this, or any other Emerald publication, then please use our Emerald for Authors service. Information about how to choose which publication to write for and submission guidelines are available for all. Please visit www.emeraldinsight.com/authors for more information. About Emerald www.emeraldinsight.comWith over forty years' experience, Emerald Group Publishing is a leading independent publisher of global research with impact in business, society, public policy and education. In total, Emerald publishes over 275 journals and more than 130 book series, as well as an extensive range of online products and services. Emerald is both COUNTER 3 and TRANSFER compliant. The organization is a partner of the Committee on Publication Ethics (COPE) and also works with Portico and the LOCKSS initiative for digital archive preservation. AbstractPurpose -Many traditional retailers use the internet as a complementary business channel while "pure player" retailers only sell products via the internet. The question of who is better at offering electronic physical distribution service quality (e-PDSQ) is open to debate. But, despite e-PDSQ's importance there are few empirical studies and most have focused on general service quality of internet shopping or web site design. The purpose of this paper is to discuss and empirically test a conceptual framework for e-PDSQ from the consumer's perspective. Design/methodology/approach -This paper follows a two-stage paradigm for scale and construct development, which is presented in a framework based on the concept of order fulfilment as a key driver in e-PDSQ. Consumer postal surveys were conducted in Edinburgh, UK. Findings -The consumer survey confirmed the appropriateness of the adopted e-PDSQ framework. The finding that price is the most important online purchasing criteria is in accordance with Verdict which suggests that price is the principle motivator in the home delivery market as the retailing market is getting more price-transparent and consumers are becoming more price-sensitive. Originality/value -Earlier work has provided insight into how e-PDSQ, represented by availability, timeliness and reliability. This paper extends this work and empirically tests and confirms an e-PDSQ framework to investigate differences between multi-channel and pure player retailers, and provides a parsimonious set of e-PDSQ variables and constructs for retailers to use to design and operate their online offerings.
PurposeMany traditional retailers use the internet as a complementary business channel and thus sell products through multiple channels. In contrast, “pure player” internet retailers only sell products via the internet. A proliferation of pure players over the past few years has intensified competition in the online shopping market and the question of who is better at offering physical distribution service quality (PDSQ), multi‐channel retailers or pure players, is open to debate. Despite PDSQ's importance in an electronic commerce environment there are few studies to date and most have focused on general service quality of internet shopping. The purpose of this paper is to discuss this phenomenon and posit a conceptual framework for further investigation.Design/methodology/approachThis paper reviews the literature to develop variables and constructs for investigation following the first stage of Churchill's paradigm for scale development, which are presented in a framework based on the concept of order fulfilment as a key driver in electronic PDSQ, or e‐PDSQ.Research limitations/implicationsThe framework is presented for future investigation, thus there is no empirical study in this paper.Practical implicationsPDSQ has strategic importance for retailers to achieve competitive advantage and offer superior customer service, particularly for pure players as they are considered intangible services compared to their multi‐channel competitors. This importance also extends to the e‐commerce environment.Originality/valueEarlier work has provided insight into how e‐PDSQ, represented by availability, timeliness and reliability, is affected by pricing, transactions and firms. This paper extends this work and presents an e‐PDSQ framework to investigate differences between multi‐channel and pure player retailers.
PurposeThe growth in online shopping has presented challenges for physical distribution service quality (PDSQ) provided by retailers, including both multi‐channel and pure players, and logistics service providers (LSPs). Issues emerging from a consumer survey regarding electronic physical distribution service quality (e‐PDSQ) informed this paper's research, which aims to consider this phenomenon.Design/methodology/approachThe research study employed qualitative interviews with retailers, logistics service providers and experts to consider the consumer survey findings and discuss the current market situation and suggestions for improvement.FindingsInterviewees confirmed that pure players offer better e‐PDSQ than multi‐channel retailers as well as important constructs of availability, time, condition and returns regarding this phenomenon, but also raised issues of relationships between retailers and LSPs and costs regarding service trade‐offs.Research limitations/implicationsThe research undertaken was exploratory and will require further and wider testing in other contexts and geographical areas to assure external validity.Practical implicationsThe findings have strategic importance for online retailers and LSPs to achieve competitive advantage and offer superior customer service.Originality/valueThis paper extends earlier, limited work on e‐PDSQ and considers retailer and LSP points of view concerning previous research into consumer expectations and perceptions of e‐PDSQ.
The outbreak of COVID-19 has spread across the world and was characterized as a pandemic. To protect medical laboratory personnel from infection, most laboratories inactivate the clinical samples before testing. However, the effect of inactivation on the detection results remains unknown. Here, we used a digital PCR assay to determine the absolute SARS-CoV-2 RNA copy number in 63 nasopharyngeal samples and assess the effect of inactivation methods on viral RNA copy number. Viral inactivation was performed with three different methods: (1) incubation with TRIzol® LS Reagent for 10 min at room temperature, (2) heating in a waterbath at 56°C for 30 min, and (3) high-temperature treatment, including 121°C autoclaving for 20 min, 100°C boiling for 20 min, and 80°C heating for 20 min. Compared to the amount of RNA in the original sample, TRIzol treatment destroyed 47.54% of N gene and 39.85% of ORF 1ab. For samples treated at 56°C for 30 min, the copy number of N gene and ORF 1ab was reduced by 48.55% and 56.40%, respectively. Viral RNA copy number dropped by 50–66% after 80°C heating for 20 min. Nearly no viral RNA was detected after autoclaving at 121°C or boiling at 100°C for 20 min. These results indicated that inactivation reduced the quantity of detectable viral RNA and may cause false negative results especially in weakly positive cases. Thus, TRIzol is recommended for sample inactivation in comparison to heat inactivation as Trizol has the least effect on RNA copy number among the tested methods.
A study is presented of the modeling and implementation of different concepts for linear feedback control of a single-mode resonance shallow cavity flow. When a physics-based linear model is used for cavity pressure oscillations, an H ∞ controller was designed and tested experimentally. It significantly reduced the main Rossiter mode for which it was designed, while leading to strong oscillations at other Rossiter modes. Other linear control methods such as Smith predictor controller and proportional integral derivative (PID) controller exhibited similar results. The ineffectiveness of using fixed linear models in the design of controllers for the cavity flows is discussed. A modification of the PID design produced a parallel-proportional with time-delay controller that remedied this problem by placing zeros at the frequencies corresponding to other resonance states. Interestingly, it was observed that introducing the same zero to the H ∞ controller can also successfully avoid the strong oscillations at other Rossiter modes otherwise observed in the single-mode-based design. The parallel-proportional with time-delay controller was compared to a very effective open-loop method for reducing cavity resonance and exhibited superior robustness with respect to departure of the Mach number from the design conditions. An interpretation is presented for the physical mechanisms by which the open-loop forcing and the parallel-proportional with time-delay controllers reduce the cavity flow noise. The results support the idea that both controls induce in the system a rapid switching between modes competing for the available energy that can be extracted from the mean flow.
In our recent work we presented preliminary results for subsonic cavity flow control using a reduced-order model based feedback control derived from experimental measurements. The model was developed using the Proper Orthogonal Decomposition of PIV images in conjunction with the Galerkin projection of the Navier-Stokes equations onto the resulting spatial eigenfunctions. A linear-quadratic optimal controller was designed to reduce cavity flow resonance by controlling the time coefficient and tested in the experiments. The stochastic estimation method was used for real-time estimation of the corresponding time coefficients from 4 dynamic surface pressure measurements. The results obtained showed that the controller was capable of reducing the cavity flow resonance at the design Mach 0.3 flow, as well as at other flows with slightly different Mach number. In the present work we present several improvements made to the method. The reduced order model was derived from a larger set of PIV measurements and we used 6 sensors for the stochastic estimation of the instantaneous time coefficients. The reduced order model so obtained shows a better convergence of the time coefficients. This combined with the 6sensor estimation improves the control performance while using a scaling factor closer to the theoretically expected value. The controller also performed better in off design flow conditions.
One of the current three main thrust areas of the Collaborative Center of Control Science (CCCS) at The Ohio State University is feedback control of aerodynamic flows. Synergistic capabilities of the flow control team include all of the required multidisciplinary areas of flow simulations, low-dimensional and reduced-order modeling, controller design, and experimental integration and implementation of the components along with actuators and sensors. The initial application chosen for study is closed-loop control of shallow subsonic cavity flows. We have made significant progress in the development of various components necessary for reduced-order model based control strategy, which will be presented and discussed in this paper. Stochastic estimation was used to show that surface pressure measurements along with the reduced-order model based on flow-field variables can be used for closed-loop control. Linear controllers such as H ∞ , Smith predictor, and PID were implemented experimentally with various degrees of success. The results showed limitations of linear controllers for cavity flow with inherent nonlinear dynamics. Detailed experimental work further explored the physics and showed the highly non-linear nature of the cavity flow and the effects of forcing on the flow structure.
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