Skip to main content Skip to navigation
Showcase GPSA

Coordinated Voltage Control for Conservation Voltage Reduction in Power Distribution Systems

Coordinated Voltage Control for Conservation Voltage Reduction in Power Distribution Systems

Primary Author: Rahul Jha

Faculty Sponsor: Anamika Dubey

 

Primary College/Unit: Voiland College of Engineering and Architecture

Category: Engineering and Environmental Science

Campus: Pullman

 

Abstract:

 

Principle Topic

An efficient operation of the distribution grid can be achieved using network-level optimization modeled as a distribution optimal power flow (D-OPF) problem. However, the variable power generation profiles of distributed energy resources (DERs) may render the optimal control decisions that are obtained in advance using D-OPF methods to sub-optimal.

 

Method

For conservation voltage reduction (CVR), a coordinated centralized and local control approach is developed that simultaneously achieves the network-level objective, while mitigating the impacts of DERs variability on optimal control set-points. The centralized controller solves a D-OPF problem for substation power reduction using a bi-level approach to control the system’s legacy voltage control devices (voltage regulator and capacitor banks) and smart inverters. A penalty successive linear programming (PSLP) approach is used to obtain a computationally tractable D-OPF model. Next, an adaptive volt-var droop control for the local control of smart inverters is proposed to minimize the voltage deviations (due to DERs variability) with respect to the centralized control set-points.

 

Results/Implications

The proposed coordinated control approach is validated using the modified IEEE 123-node test system which has four voltage regulators, four capacitor banks and twenty-six DERs.  The results show that the proposed control simultaneously reduces the power consumption from the substation to achieve CVR objective and voltage violations due to DERs variability.

 

Stigma As a Moderator for the Relation between Race and Autism Spectrum Disorder Diagnoses

Stigma As a Moderator for the Relation between Race and Autism Spectrum Disorder Diagnoses

Primary Author: Shelby Johnson

Faculty Sponsor: Tammy Barry

 

Primary College/Unit: Arts and Sciences

Category: Physical and Social Sciences

Campus: Pullman

 

Abstract:

 

Principal topic: Past research has indicated that minority racial and ethnic groups in the United States face more barriers to accurate and timely autism spectrum disorder (ASD) diagnoses than their white counterparts. This project is designed to determine if stigma moderates the relation between race and the time lapse between symptom onset and ASD diagnosis.

 

Method: Data were collected from 152 parents of children with an ASD diagnosis. Parents reported at what age their child began showing signs of ASD, what age the child was officially diagnosed with ASD, and child’s race; they also completed a stigma scale measuring affective, behavioral, and cognitive stigma.

 

Results/implications: A t-test indicated that the time lapse between symptom onset and diagnosis did not significantly differ between white and non-white participants. Furthermore, the time lapse between symptom onset and diagnosis did not significantly relate to stigma. However, a regression analysis indicated that stigma moderated the relation between race and the time lapse in diagnosis when comparing white participants (n = 123, M = 21.63, SD = 17.36) to non-white participants (n = 29, M = 17.66, SD = 18.86) p = .02. These data suggest race and stigma play a significant role in how long it takes a child to receive an ASD diagnosis. Although neither race nor stigma individually related to the time lapse between onset and diagnosis, their interaction was significant. Parents of minority children who reported experiencing higher levels of stigma also reported the shortest time lapse between symptom onset and diagnosis.

 

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.