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Network Loss Analysis of Low-Voltage Low Power DC Microgrids for Rural Electrification

Network Loss Analysis of Low-Voltage Low Power DC Microgrids for Rural Electrification

Primary Author: Rabia Khan

Faculty Sponsor: Noel Schulz

 

Primary College/Unit: Voiland College of Engineering and Architecture

Category: Engineering and Environmental Science

Campus: Pullman

 

Abstract:

Principal topic

The topic is “Network Loss Analysis of Low-Voltage Low Power DC Microgrids for Rural Electrification”. Millions of people around the globe are suffering  from energy poverty, particularly the inhabitants of Africa  and South-East Asia. Electrification through national grids is cost-prohibitive with limited power generation sources in the  third world countries. The low voltage, low-power islanded DC microgrids are a practical option for rural electrification.

 

Method

In this research work, the detailed network loss analysis of four different microgrid architectures is performed using the modified Newton-Raphson power flow for DC systems. These architectures include, 1) Centralized generation centralized storage (CGCS), 2) Centralized generation distributed storage (CGDS), 3) Distributed generation centralized storage (DGCS), and 4) Distributed generation distributed storage (DGDS), which are implemented with both radial and ring interconnection schemes using time-varying load demand and PV generation.

 

Results/implications

Comparative performance analysis of these architectures is done using the modified Newton-Raphson power flow method at different low-voltage levels and conductor sizes. The DGDS architecture with ring interconnection is the most efficient and reliable with an advantage of scalability, usage diversity, and mutual resource sharing capability. However, ring interconnection requires extra conductors, which increase the cost. So, a tradeoff between conductor size, voltage level, cost, interconnection scheme, and reliability is to be made while selecting the components for the microgrid architecture. The efficiency of systems is higher for conductors with lower AWG sizes but it is more expensive. So, trade-off between conductor size, voltage level, cost, interconnection scheme, and reliability is important.

 

The Effects of Absolute Status, Relative Status, and Patriarchal Culture on the Victimization of Women: An International Comparative Study

The Effects of Absolute Status, Relative Status, and Patriarchal Culture on the Victimization of Women: An International Comparative Study

Primary Author: Sohee Kim

Faculty Sponsor: Melanie-Angela Neuilly

 

Primary College/Unit: Arts and Sciences

Category: Physical and Social Sciences

Campus: Pullman

 

Abstract:

 

A rising number of concerns about violence against women has resulted in various explanatory theoretical frameworks being emerged and developed. For example, several feminist theories have shed light on the role of women’s socioeconomic status and gender stratification relative to men in order to predict violence against women. Meanwhile, another branch of feminist theory argues that female victimization stems from the cultural disadvantage women incur in the patriarchal structure. Evidence has far been inconclusive, however. To fill this gap, we investigate the following questions: Which indicators are more predictive of women’s victimization? Will patriarchal culture play a role in explaining violence against women? To answer these questions, this study uses a multilevel mixed-effects model with logit link functions with a dataset comprising 36,286 respondents from 54 nations. Results show that women with higher absolute and relative status are victimized at higher rates at the individual-level, only supporting the backlash hypothesis. Among country-level variables, absolute status and relative status of women indicate significant effects, but the Marxist feminist argument is also supported. Furthermore, there is a significant positive association between patriarchal culture and women’s victimization. These results indicate we should deliver the message saying that improving gender equality is not the signal of threats to men’s rights in society, rather it is given rights for women.

 

Self-disclosure on Facebook: “Self” and “Others” from social penetration perspective

Self-disclosure on Facebook: “Self” and “Others” from social penetration perspective

Primary Author: Ka Lai Lee

Faculty Sponsor: Porismita Borah

 

Primary College/Unit: Edward R. Murrow College of Communication

Category: Physical and Social Sciences

Campus: Pullman

 

Abstract:

Principal topic

Previous studies found that online self-disclosure has various offline implications such as friendship development and subjective well-being. Thus, it is imperative to understand the underlying mechanism of online self-disclosure. As such, the current study examined the simultaneous influences of “self” (i.e., personal involvement with the information to be posted) and “others” (i.e., audience diversity in the network) in self-disclosure on Facebook.

 

Method

Based on social penetration theory, we conducted a 2 (high versus low personal involvement) x 2 (high versus low audience diversity) factorial design experiment with different hypothetical scenarios. A total of 241 young adults participated and they were asked to imagine being the main roles who were deciding whether or not to share the hypothetical stories on Facebook. After the participants read the scenarios, they were instructed to write down whatever thoughts that came across their minds and fill in items which assessed their considerations, Facebook usage and demographics.

 

Results/implications

The results suggested that information that is highly involved with oneself would trigger extended thought elaborations in deciding self-disclosure. However, surprisingly, the influence from audience diversity in the network on self-disclosure was revealed to be minimal. The study underscored the self-serving purpose of self-disclosure online, such that young adults would chiefly focus on considerations surrounding themselves instead of the audience representation. The current study pointed to the potential domination of self-concerns more than audience-related considerations for self-disclosure on SNSs for young adults. Future directions are discussed.

 

The Purpose of Fashion Shows Through the Lens of Media’s History

The Purpose of Fashion Shows Through the Lens of Media’s History

Primary Author: Lindsay McCoy

Faculty Sponsor: Jihyeong Son

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Business, Communication, and Politial Sciences

Campus: Pullman

 

Abstract:

 

Fashion shows are a popular spectacle that promotes human expression and aesthetic, yet few studies examine their history, purpose, or influential factors. In particular, no study has previously examined how communication technology has impacted fashion shows in terms of media coverage, presentation format, and purpose throughout history.

 

Using qualitative content analysis with grounded theory utilizing secondary data from print books and internet sources using pre-defined key words and phrases, the histories of fashion shows and media were analyzed and compared to answer three research questions: What is the purpose and function of fashion shows throughout history?; How has the communication of fashion shows changed throughout various media transformations?; How did each of the various media types impact fashion shows and which had the greatest impact?

 

It was found that the invention of television and the radio had the greatest impact. Fashion shows in earlier decades were reserved for the elite classes, but television and radio allowed all members of society to become involved. The invention of the internet and social media provided the ability to virtually watch shows in real time, regardless of social status or location.

 

One implication is that fashion shows will continue to evolve with changing communication technology; therefore it is pertinent to monitor how fashion shows adapt in the future to understand how their purpose changes and what role they will play in society. This research study also creates a timeline framework for future research to build upon.

 

Highly Structured Nurse-to-Patient Interactions in an Acute Care Hospital ICU Reduces MRSA Transmission When Limited to Assigned Patient Groups: A Mathematical Model Approach

Highly Structured Nurse-to-Patient Interactions in an Acute Care Hospital ICU Reduces MRSA Transmission When Limited to Assigned Patient Groups: A Mathematical Model Approach

Primary Author: Matthew Mietchen

Faculty Sponsor: Eric Lofgen

 

Primary College/Unit: College of Veterinary Medicine

Category: Medical and Life Sciences

Campus: Pullman

 

Abstract:

PRINCIPLE TOPIC

The importance of nurse-to-patient contact in hospital settings for reducing healthcare acquired infections (HAIs) has been well documented. However, it is not well understood how specific interaction patterns effect pathogen transmission. Hospital staffing challenges are a reality, and in addition, are difficult and expensive to study. Using disease transmission models is a useful tool to explore the magnitude and the importance of patient care structure in an intensive care unit (ICU).

 

METHODS

A stochastic compartmental model of an 18-bed ICU was used to study how nurse interactions with patients affected the number of methicillin-resistant S. aureus (MRSA) acquisitions. A parameter, gamma, was introduced to represent the proportion of time a nurse spends within an assigned patient sub-group over a one year duration. The model was simulated 10,000 times with gamma being chosen randomly from a uniform distribution within the parameter range. A segmented Poisson regression model was fit to the MRSA acquisitions to detect any relationships or notable change points.

 

RESULTS

A non-linear relationship was observed, resulting in a decrease in acquisitions as the value of gamma increased. The regression model also detected a single change point in MRSA acquisitions at a gamma value of 0.40 (95% confidence interval: 0.37, 0.42). In conclusion, the proportion of time a nurse spends with an assigned group of patients may have large effects on MRSA transmission within an ICU. Highly structured nurse-to-patient contact with limited interactions outside of assigned patient sub-groups, may be important for hospital epidemiology prevention efforts.

 

Treatment of Dairy Wastewater using a Low-cost Vermifilter Technology

Treatment of Dairy Wastewater using a Low-cost Vermifilter Technology

Primary Author: Gilbert Miito

Faculty Sponsor: Pius Ndegwa

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

The dairy industry generates wastewater streams characterized by high organic and nutrient contents. When discharged untreated, the wastewater streams can lead to several environmental problems which include eutrophication, ground water contamination and greenhouse gas emission. Technologies such as membrane filtration, struvite precipitation, Ammonia stripping, and aerobic treatment have been suggested as viable treatment and recovery options, but these are expensive in terms of resources, labor and energy. Vermifiltration is an emerging low-cost and environmentally sustainable technology for the treatment of wastewater and recovery of nutrients using earthworms. This study evaluated the efficacy of a pilot scale vermifilter at treating a side-stream of dairy wastewater on a commercial dairy. The vermifiltration unit was set up and was monitored for a period of 6 months to study the effect of the process on the chemical oxygen demand, total ammoniacal-nitrogen, orthophosphates, and gas emissions. Influent and effluent samples were collected bi-weekly and analyzed using standardized methods. Gas emissions were also measured on site using the static chamber method. Overall, the vermifilter removed 42% of Chemical Oxygen Demand, 80% of Total Ammoniacal Nitrogen, and 7% of ortho-Phosphates. The vermifilter reduced ammonia emissions by 84–100%, nitrous oxide by 0–59%, carbon dioxide by 58–82% and Methane by 95–99%. These removals are attributed to the synergistic action of earthworms and the microorganisms in the units. Basing on these findings, vermifiltration is a viable low-cost alternative for nutrient recovery and treatment of dairy water while also reducing gaseous emissions.

 

Sensory Detection of Wine Faults Over Time Using Flash Profiling and the Electronic Tongue

Sensory Detection of Wine Faults Over Time Using Flash Profiling and the Electronic Tongue

Primary Author: Victoria Minette

Faculty Sponsor: Carolyn Ross

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

Wine faults are negative sensory attributes in wine that may result in large economic losses for wineries and can be attributed to the growth of spoilage microorganisms.  Due to quality changes happening quickly, detection is critical, therefore the use of a rapid sensory profiling method, such as flash profiling, is very useful.  Thus, the objective of this study was to use the electronic tongue (e-tongue) and a rapid sensory method, flash sensory profiling, to evaluate changes in wine over time due to the presence of different spoilage microorganisms.

 

Merlot wine was bottled and inoculated with different common wine spoilage microorganisms.  Starting at Day 0, wines were analyzed weekly until Day 42 using the e-tongue, microbial plating and flash profiling. PCA, GPA, and AHC analyses were performed.

 

Over 42 days of storage, both flash profiling and e-tongue analyses differentiated the wines. The e-tongue displayed low discrimination among the different microorganisms through Day 14 of storage. However, at Day 21, the discrimination index increased to 91%, indicating the e-tongue was able to differentiate among the samples.  From the flash profiling data, citations associated with wine faults reached a peak at Day 42 of microbial growth.  As the e-tongue detected differences starting at Day 21, but sensory differences were not apparent until Day 42, these results suggest that the e-tongue is a useful tool for early detection of wine faults.  The application of these novel techniques may be the key to detecting and limiting financial losses associated with wine faults.

 

Feedback in Computer-Assisted Language Learning: Meta-Analysis

Feedback in Computer-Assisted Language Learning: Meta-Analysis

Primary Author: Adnan Mohamed

Faculty Sponsor: Joy Egbert

 

Primary College/Unit: College of Education

Category: Arts and Education Sciences

Campus: Pullman

 

Abstract:

 

Feedback is a well-known advantage for language learning. Research on feedback in Computer-Assisted Language Learning (CALL) demonstrates that feedback has a significant effect on student language learning. However, a comprehensive review (e.g., Azevedo & Bernard, 1995; Kang & Han 2015; Li, 2010) revealed that there has never been a meta-analysis synthesizing the effectiveness of feedback in CALL studies and the moderators moderating the effectiveness of feedback in CALL. With the aim of summarizing years of research on feedback in Computer-Assisted Language Learning (CALL) studies and identifying the moderators of feedback in CALL, a meta-analysis was conducted. By establishing rigorous inclusion and exclusion criteria, the investigator located 21 primary studies that met clearly defined inclusion and exclusion criteria. The findings indicated under the Random Effect (RE) model that feedback in CALL has a significant medium effect size on student language learning outcomes (g = 0.56). However, the effectiveness of feedback in CALL is moderated by a host of variables, including learners’ proficiency, measures of proficiency, and so on.

 

Consumer acceptance of a ready-to-eat meal during storage using a home-use test

Consumer acceptance of a ready-to-eat meal during storage using a home-use test

Primary Author: Maria Montero

Faculty Sponsor: Carolyn Ross

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

A home-use test (HUT) is a method on which a product is consumed in-home under common daily use circumstances. One product that benefits from being evaluated in-home are ready-to-eat meals (RTE). RTE must be processed so they are microbially safe, and a novel method to accomplish this is microwave-assisted-pasteurization (MAPS). Therefore, this study determined consumers’ acceptance of MAPS-processed jambalaya and control through an on-line HUT over a 12-week storage period. Paralleling the HUT, an online auction determined consumers’ willingness to pay. Consumers (n=50) evaluated MAPS-processed jambalaya stored at 2?C and a control (cooked-frozen jambalaya stored at -31oC) after 2, 8 and 12 weeks of storage. Acceptance of different sensory attributes (aroma, appearance, flavor, texture) was measured for both jambalaya samples using an online survey. After tasting, consumers participated in an online auction to bid on the meal they previously sampled- this was used to estimate their willingness to pay for each meal.

Results showed that the processing method (MAPS vs. control) didn’t affect the measured sensory attributes. No significant sensory changes were observed in most of the tested attributes of the jambalaya samples due to storage time; only flavor liking decreased over time. For the online auction, the bid mean values ranged from $3.48-3.74 for the MAPS-processed jambalaya and from $3.33-3.56 for the control, similar to the price of commercially available jambalaya meals. Using a HUT for evaluating consumers’ acceptance of MAPS-processed jambalaya seems like an effective way of testing acceptance of an RTE in a more realistic environment.

 

The influence of structure locations on wildfire perimeters.

The influence of structure locations on wildfire perimeters.

Primary Author: Joshua Olsen

Faculty Sponsor: Jonathan Yoder

 

Primary College/Unit: Agricultural, Human and Natural Resource Sciences

Category: Agricultural and Natural Resource Sciences

Campus: Pullman

 

Abstract:

 

PRINCIPAL TOPIC

Wildfires suppression in the United States has cost an average of $1.8 billion annually over the past 10 years and wildfire damages have frequently exceeded 10 times that amount. A major reason for the extreme cost of wildfires is the presence of man-made structures.

 

Despite the large associated cost, the influence that structures have on wildfire spread has yet to be evaluated. We address this gap by analyzing structure density around fire perimeters to understand the relationship between structures and wildfire spread.

 

METHODS

Using an innovative dataset we evaluate structure presence around wildfires at a finer scale than has previously been possible. We analyze the present of structures per 1,000 acres across a 32 year timespan in the Western United States.

 

RESULTS/IMPLICATIONS

We find that a disproportionate number of structures reside in a 120 meter bandwidth around fire perimeters. We also find that structure density is highest in the first 30 meters outside of fire perimeters, suggesting that structures are more likely to be found immediately outside fire perimeters than inside fire perimeters. Structure locations are determined prior to fire ignitions which implies that structure locations influence final fire perimeters.

This trend is consistent across all 11 Western United States. This finding has implications for land development policy as well as policies governing prioritization for firefighting resources. For example, our results suggest that current fire suppression is largely guided by the presence of structures. This implies that structure protection may be prioritized over minimizing fire growth.