255 research outputs found
Particle Density, Particle Size, and Nutrient Distribution of Flushed Dairy Manure
No full textThe handling of large volumes of liquid manure produced by hydraulic flushing systems can be challenging for dairy farmers. The high solid content in flushed dairy manure causes numerous challenges during manure handling, and the high nutrient content limits the amount of manure that can be applied onto cropland. The knowledge of particle density, particle size, and nutrient distribution of flushed dairy manure would allow dairy farmers to select appropriate manure treatment technologies and make better manure nutrient management on their farms. The major goal of this study was to understand the particle density, particle size, and total nitrogen (TN) and total phosphorous (TP) distributions of flushed dairy manure by using four commercial dairies in Southern Idaho as case studies. The study also aimed to examine the statistical significance of using different pore-sized inclined screen separators for solids and nutrients removal from flushed dairy manures of the four dairies. The particle densities of flushed dairy manure solids were determined by the pycnometer method using a methanol medium. A new technique—wet sieving combined with the hydrometer-pipette method—was used to determine the particle size and nutrient distributions of the flushed dairy manures. Nutrient analyses were carried out using the Hach methods: TNT 880 for TN and TNT 845 for TP. The flushed dairy manures of the four dairies differed in the initial total solid as well as nutrient contents with total solids (TS) ranging from 2.23% to 7.69%, TN ranging from 0.08% to 0.19%, and TP ranging from 0.04% to 0.13%. The particle densities of flushed dairy manure solids were found to vary with particle size, and the average particle densities of dried solids in flushed manures of dairies, #1, #2, #3, and #4 were found to be 1.48, 1.39, 1.37, and 1.30 g/cm3, respectively, much lower than the commonly used particle density of soils of 2.65 g/cm3. The distributions of solids and nutrients in flushed dairy manures also varied between the four dairies and were found to be site-specific. However, regardless of the dairy, the majority of TS, TN, and TP in flushed manures were observed at diameters smaller than 0.5 mm. Dairies, #1, #2, #3, and #4 had 63.85%, 58.17%, 57.94%, and 51.50% of TS smaller than 0.5 mm in diameter. Similarly, the percentages of TN and TP observed at diameters smaller than 0.5 mm for dairies, #1, #2, #3, and #4 were 72.00%, 75.14%, 75.76%, and 61.92% and 85.64%, 70.58%, 69.28%, and 61.35%, respectively. The statistical differences between the solid and nutrient removal capacities of different pore-sized inclined screen separators were found to be dairy-specific. From this study, it was estimated that 0.5-mm pore-sized inclined screen separators would remove between 25.41% and 37.40% of TS, 24.24% and 38.08% of TN, and 14.36% and 38.65% of TP from flushed dairy manures with initial TS ranging from 2.23% to 7.69%. This suggests that the inclined screen separators with pore size larger than 0.5 mm would remove only a fraction of total solids, total nitrogen, and total phosphorus from flushed dairy manures, and most of the TS, TN, and TP would remain in the liquid fraction after solid-liquid separation. Therefore, commercial dairies that rely on inclined screen separators with pore sizes larger than 0.5 mm for solid-liquid separation might need to look beyond the 0.5-mm pore-sized screen separators to remove higher quantities of solids and nutrients from their flushed dairy manures.masters, M.S., Water Resources -- University of Idaho - College of Graduate Studies, 2021-0
ANAEROBIC CO-DIGESTION OF DAIRY MANURE AND POTATO WASTE
No full textDairy and potato are two important agricultural commodities in Idaho. Both the dairy and potato processing industries produce a huge amount of waste which could cause environmental pollution. To minimize the impact of potential pollution associated with dairy manure (DM) and potato waste (PW), anaerobic co-digestion has been considered as one of the best treatment process. The purpose of this research is to evaluate the anaerobic co-digestion of dairy manure and potato waste in terms of process stability, biogas generation, construction and operating costs, and potential revenue. For this purpose, I conducted 1) a literature review, 2) a lab study on anaerobic co-digestion of dairy manure and potato waste at three different temperature ranges (ambient (20-25˚C), mesophilic (35-37˚C) and thermophilic (55-57˚C) with five mixing ratios (DM:PW-100:0, 90:10, 80:20, 60:40, 40:60), and 3) a financial analysis for anaerobic digesters based on assumed different capital costs and the results from the lab co-digestion study. The literature review indicates that several types of organic waste were co-digested with DM. Dairy manure is a suitable base matter for the co-digestion process in terms of digestion process stability and methane (CH4) production (Chapter 2). The lab tests showed that co-digestion of DM with PW was better than digestion of DM alone in terms of biogas and CH4 productions (Chapter 3). The financial analysis reveals DM and PW can be used as substrate for full size anaerobic digesters to generate positive cash flow within a ten year time period. Based on this research, the following conclusions and recommendations were made:
► The ratio of DM:PW-80:20 is recommended at thermophilic temperatures and the ratio of DM:PW-90:10 was recommended at mesophilic temperatures for optimum biogas and CH4 productions.
► In cases of anaerobic digesters operated with electricity generation equipment (generators), low cost plug flow digesters (capital cost of 600/cow) operating at thermophilic temperatures are recommended.
* The ratio of DM:PW-90:10 or 80:20 is recommended while operating low cost plug flow digesters at thermophilic temperatures.
► In cases of anaerobic digesters operated without electricity generation equipment (generators), completely mixed or high or low cost plug flow digesters can be used.
* The ratio of DM:PW-80:20 is recommended for completely mixed digesters operated at thermophilic temperatures;
* The ratio of DM:PW-90:10 or 80:20 is recommended for high cost plug flow digesters (capital cost of 1,000/cow) operated at thermophilic temperatures;
* All of the four co-digested mixing ratios (i.e. DM:PW-90:10 or 80:20 or 60:40 or 40:60) are good for low cost plug flow digesters (capital cost of $600/cow) operated at thermophilic temperatures. The ratio of DM:PW-90:10 is recommended for positive cash flow within the ten year period if the low cost plug flow digesters are operated at mesophilic temperatures.Thesis (Ph.D., Environmental Science)--University of Idaho, May 201
Contribution Based Author Categorization to Calculate Author Performance Index
No full textDespite the widely used author contribution criteria, unethical authorship practices such as guest, ghost, and honorary authorship remains largely unsolved. We have identified six major reasons by analyzing 78 published papers addressing unethical authorship practice. Those are lack of: (i) awareness about and (ii) compliance with authorship criteria, (iii) universal definition and scope for determining authorship, (iv) common mechanisms for positioning an author in the list, (v) quantitative measures of intellectual contribution; and (vi) pressure to publish. As a possible measure to control unethical practice, we have evaluated the possibility to adopt an author categorization scheme – proposed according to the common understanding of how first-, co-, principal-, or corresponding- author is perceived. Based on an online opinion survey, the proposed scheme was supported by ~80% of the respondents (n=370). The impact of the proposed categorization was then evaluated using a novel mathematical tool to measure “Author Performance Index (API)” that can be higher for those who might have authored more papers as primary and/or principal authors than those as coauthors. Hence, if adopted, the proposed author categorization scheme together with the API would provide a better way to evaluate the credit of an individual as a primary and principal author
Performance evaluation of a wood-chip based biofilter using solid-phase microextraction and gas chromatography–mass spectroscopy–olfactometry
No full textA pilot-scale mobile biofilter was developed where two types of wood chips (western cedar and 2 in. hardwood) were examined to treat odor emissions from a deep-pit swine finishing facility in central Iowa. The biofilters were operated continuously for 13 weeks at different air flow rates resulting in a variable empty bed residence time (EBRT) from 1.6 to 7.3 s. During this test period, solid-phase microextraction (SPME) PDMS/DVB 65 μm fibers were used to extract volatile organic compounds (VOCs) from both the control plenum and biofilter treatments. Analyses of VOCs were carried out using a multidimentional gas chromatography–mass spectrometry–olfactometry (MDGC–MS–O) system. Results indicated that both types of chips achieved significant reductions in p-cresol, phenol, indole and skatole which represent some of the most odorous and odor-defining compounds known for swine facilities. The results also showed that maintaining proper moisture content is critical to the success of wood-chip based biofilters and that this factor is more important than media depth and residence time.This is a manuscript of an article published as Chen, Lide, Steven J. Hoff, Jacek A. Koziel, Lingshuang Cai, Brian Zelle, and Gang Sun. "Performance evaluation of a wood-chip based biofilter using solid-phase microextraction and gas chromatography–mass spectroscopy–olfactometry." Bioresource Technology 99, no. 16 (2008): 7767-7780. DOI: 10.1016/j.biortech.2008.01.085. Posted with permission.</p
Utilizing Anaerobically Digested Dairy Manure for the Cultivation of Duckweed for Biomass Production, Nutrient Assimilation, and Sugar Production
No full textNutrient management methods are needed to provide sustainable operation to livestock production that balance the costs of operation and maintenance. Cultivating duckweed on dairy wastes is considered an effective way of nutrient uptake and cycling. Duckweed cultivation has been implemented on nutrient management systems, such as constructed wetlands and waste stabilization ponds that use both domestic and swine wastewater. The objectives of this study were to (1) identify a nutrient concentration and duckweed strain that rapidly produces biomass, (2) removes nutrient content from anaerobically digested dairy manure, and (3) produces starch from nutrient starvation. To complete these objectives, this study targeted estimating growth and nutrient rate constants as well as starch yield of duckweed under different cultivation conditions. The strains of duckweed, Landoltia punctata 0128, Lemna gibba 7589, and Lemna minuta 9517 were identified as the promising candidates for their high levels of nutrient uptake, starch accumulation, and biomass production. The growth rate of the duckweed strain was assessed based on the effects of temperature, pH, dissolved oxygen, light intensity, nutrient concentration, and biomass accumulation. The nutrient uptake through duckweed cultivation on the anaerobically digested (AD) dairy manure, characterized by the changes of total nitrogen (TN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and ortho-phosphate-phosphorus (o-PO4-P), was assessed in four nutrient dilution ratios 1:5, 1:13, 1:18, and 1:27 v/v at two light intensities of 10,000 and 3,000 lux to model seasonal variation. The duckweed strain that exhibited the best biomass production, nutrient removal and starch accumulation was Landoltia punctata 0128 at a dilution ratio of 1:27 at a light intensity of 10,000 lux. The growth rate constant established from zero order kinetics for Landoltia punctata 0128 was 13.3 gm-2d-1. The rate constants for nutrient recovery were 0.122 d-1of TN, 0.136 d-1 of TKN, 0.145 d-1 of TP, and 0.173d-1 of o-PO4-P. The batch efficiency of cultivation for Landoltia punctata 0128 on dilution ratio 1:27, in terms of nutrient uptake was 38% m/m in relation to the total nitrogen removed. The starch yield was measured at 30% w/w for Landoltia punctata 0128 after the nutrient starvation process. Due to its ability to reduce nutrients from AD dairy manure, accumulate biomass at a rapid growth rate, and accumulate a high yield of starch, Landoltia punctata 0128 has great potential to become a preferred choice for nutrient recovery and biomass and bioethanol production.masters, M.Engr., Biological & Agricultural Engineering -- University of Idaho - College of Graduate Studies, 2017-0
Little Adventurers: A Nature-Based Approach to Supporting Social-Emotional Development in Early Childhood
No full textBackground:
Social-emotional development and self-regulation are foundational skills in early childhood which impact long-term academic, behavioral, and mental health outcomes. Despite growing evidence supporting the benefits of exposure to nature, many children have limited access to natural environments and most existing OT interventions and programs targeting social-emotional skill development do not incorporate this valuable context. This capstone project addressed this gap by developing a nature-based occupational therapy (OT) group to support social-emotional and regulation skill development in preschool-aged children.
Objective:
The objective of this project was to develop and implement a nature-based occupational therapy group for preschool children at risk for social-emotional and self-regulation challenges and to evaluate the program’s perceived effectiveness through caregiver and teacher feedback.
ACOTE Area:
The primary ACOTE area of this project was Program Development and Evaluation. Secondary areas included Clinical and Education.
Methods:
The development of the group program was guided by a literature review, theoretical frameworks (ECO-Therapy Model, Attention Restoration Theory, Biophilia Hypothesis), and a needs assessment via key informant interviews. Two 9-week nature-based OT groups were implemented with eight children ages 3–5, divided by developmental needs. The group was primarily conducted outdoors and intentionally integrated natural elements to harness the benefits of engaging with nature. Sessions targeted emotional regulation and social skills through structured outdoor activities, social stories, a modified ALERT program, introduction of regulation techniques, modeling, and practicing of skills in a natural context with peers and adult guidance as needed. Evaluation of the group programming was conducted primarily via a thematic analysis of teacher and caregiver surveys. Informal assessments of group progress and goal tracking were also used as secondary methods of evaluation.
Results:
Survey responses were received from 7 out of 12 caregivers and teachers. The feedback indicated overall positive perceptions of the group program. The caregivers and teachers noted that the educational resources provided along with the group were helpful in developing a shared language around emotional regulation (e.g., “fast vs. steady engines”) and learning new methods to support their students or children. Respondents’ perceptions of behavioral changes in the group participants were mixed, with some noting improved confidence and self-awareness and generalization of skills to home and classroom environments and others noting no changes. The small group format was highlighted as a strength, and the natural setting was perceived to enhance engagement and attention. Suggestions included increased communication frequency and more individualized feedback. Additionally, the output of this project provides a set of adaptable, low-cost session plans and associated caregiver educational resources to support implementation of future programming.
Conclusions and Relevance:
This project supports the growing evidence that nature-based OT interventions can promote social-emotional and self-regulation skills in early childhood. The outdoor context was perceived to support emotional safety, engagement, and skill generalization, aligning with existing theories. While limitations included short program duration, influence of external factors such as weather, and a small sample size for surveys, findings suggest there is a meaningful potential for nature-based OT interventions in school and community settings. The program also provides a framework and offers practical tools for clinicians and educators to sustainably implement future nature-based OT groups.Doctor of Occupational Therapy (OTD)Occupational Therap
Charge transport mechanisms in corona charged polymeric materials
No full textPolymeric materials have been widely used as an insulator due to their excellent electrical properties, light weight and low cost. Surface potential measurement is one of the simplest and low cost tools to gauge electrical properties of materials. Once charged, the surface charges or surface potential tend to decay over a period of time, and the exact pattern of the decay represents the characteristic of the material. For corona charged sample, it has been observed that the potential of sample with an initial high surface potential decays faster than that with an initial lower surface potential, known as the cross-over phenomenon. Various theories and models have been proposed to explain the phenomenon. The common feature of these models is that they are all based on single charge carrier injection from corona charged surface. With the recent experimental results on comparing different types of ground of corona charged low density polyethylene sample, bipolar charge injection from both electrodes has been verified. Based on this fact, a new model based on bipolar charge injection has been proposed. In this thesis, the detail of the new model was tested both experimentally and numerically. The new simulation results show that several features experimentally observed can be readily revealed using the bipolar charge injection model. More importantly, the modelling can illustrate charge dynamics across the sample and allows one to extract parameters that are associated with material properties. The effect on different charging polarities and charging times were also discussed in the thesis. Additionally, experiments have been done to nano polyimide materials and the results clearly show that adding different amounts of nano-particles can change the material's electrical property
Magnetic field effect on capacitance and photocurrent properties of metal oxides
No full textThis item is available only to currently enrolled UTSA students, faculty or staff. To download, navigate to Log In in the top right-hand corner of this screen, then select Log in with my UTSA ID.This dissertation focuses on the study of the effect of magnetic field on capacitance and photocurrent, all of which give some insight into the magneto-electric/magneto-optical coupling in dielectric and photovoltaic materials and devices. The main study of this dissertation focuses on magnetic enhancement of capacitance and photocurrent.
(i) The magnetic field effect on the capacitance of GaFeO3-ionic liquid-GaFeO3 composite material was examined. Up to 2.35 folds tunability could be achieved with voltage 10 V and magnetic field strength 1542 Oe. A mechanism which takes account of the coupling between the ionic liquid layer and the dielectric layer was presented. The effect shows a possible route to use the ionic liquid integrated with the dielectric material and suggests a simple way to introduce tunable dielectric permittivity.
(ii) A model that charge gradient would result in the coexisting magneto-resistance and -capacitance tunability in material systems is proposed. Coexisting of tunable magneto-resistance and -capacitance in Sm2Ga2Fe 2O9 is observed. The model agrees with the experimental result.
(iii) Two lithium based dielectric materials Li2ZnSiO 4 and Li4SiO4 were chosen for the investigation of photocurrent and photovoltage under a magnetic field. It is demonstrated that high magnetic field enhancement of photovoltage and photocurrent could be achieved in these two dielectric lossy materials, Li2ZnSiO 4 and Li4SiO4. 3850% of photovoltage tunability with magnetic field 0.4T and 3841% of photocurrent tunability with magnetic field 0.4 T in Li2ZnSiO4, 132.8% of photovoltage tunability and 132.5% of photocurrent tunability in Li4SiO4 are reported. A mechanism which considers the effects of electron/nuclear spin mixing and interaction under the magnetic field was proposed. This introduces large tunability and makes them suitable for practical application in optoelectronic technologies.
(iv) Multi-bands in the magneto-photocurrent spectrum of GaI3O 9 are reported. Their formation is considered to be due to the effect of quantum state transitions and quansi-resonant electronic polarization.
These results establish that the magneto-electro and magneto-opto coupling are importance for practical application of the material system and the application of the magnetic field may be useful for modification of the capacitance and photocurrent properties in the metal oxides. The current studies have shown some interesting features of the use of the magneto-electro and magneto-opto coupling in several metal oxides, which makes this research outcome could provide possible application on the performance improvement of energy harvester, solar cell and magnetometer. Nevertheless, the main attraction for studies of magneto-electro and magneto-opto coupling in the metal oxide might exist because the metal oxides are resource-abundant, non-toxic and easily-synthesized, and their mechanisms of magneto-capacitance/magneto-photocurrent are still need to be explored. Not until a clear physical/chemical picture of these materials is established, the work on this subject can be continued.Electrical and Computer Engineerin
The need to quantify authors’ relative intellectual contributions in a multi-author paper
No full textMeasuring the contribution of each author of a multi-author paper has been a long standing concern. As a possible solution to this, we propose a list of intellectual activities and logistic support activities that might be involved in the production of a research paper. We then develop a quantitative approach to estimate an author's relative intellectual contribution to a published work. An author's relative intellectual contribution is calculated as the percent contribution of an author to each intellectual activity involved in the production of the paper multiplied by a weighing factor for each intellectual activity. The relative intellectual contribution calculated in this way can be used to determine the position of an author in the author list of a paper. Second, a corrected citation index for each author, called the T-index, can be calculated by multiplying the relative intellectual contribution by the total citations received by a paper. The proposed approach can be used to measure the impact of an author of a multi-authored paper in a more accurate way than either giving each author full credit or dividing credit equally. Our proposal not only resolves the long standing concern for the fair distribution of each author's credit depending on his/her contribution, but it will also, hopefully, discourage addition of non-contributing authors to a paper
Mitigating odors from animal facilities using biofilters
No full textMitigating odors from livestock sites using biofilters was addressed in this dissertation which is organized in paper format and comprises a literature review paper and two original research papers. In the first literature review paper, both the laboratory and field research from 1997 to 2008 was reviewed to give an up-to-date perspective of studies on the mitigation of odors and volatile organic compounds (VOCs) relating to agricultural facilities using biofilters. A mobile biofiter testing system was developed which can be used at field conditions to evaluate biofilter performance at variable media types, empty bed residence times (EBRT) and media moisture contents. A field study for mitigating odors and odorous compounds from a deep-pit swine finishing facility in central Iowa was conducted to test two types of wood chip media (western cedar and two inch hardwood) using the mobile biofilter testing system. The biofilter testing system was continuously operated and evaluated at different media moisture content levels and different air flow rates resulting in a variable EBRT from 1.6 to 7.3 sec. A dynamic forced-choice olfactometer was used to evaluate odor concentrations from both the control plenum and biofilter treatments. Hydrogen sulfide and ammonia concentrations were also measured from these olfactometry samples. Solid-phase microextraction fibers were used to extract VOCs from both the control plenum and biofilter treatments. Analyses of VOCs and its corresponding individual odors were carried out using a gas chromatography-mass spectrometry-olfactometry (GC-MS-O) system. Pressure drop characteristics through the biofilters packed with western cedar and hardwood media were monitored. The reduction efficiency and pressure drop characteristics obtained with the wood chip-based biofilters indicate the feasibility of farm-level applications of wood chip-based biofilters for reducing swine building odors. The results also showed that both a proper media moisture content and a minimum EBRT were critical to a successful wood chip-based biofilter.</p
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