Developing uniformly formatted, densified feedstock from lignocellulosic biomass is of interest to achieve consistent physical properties such as size and shape, bulk and unit density, and ...durability, which significantly influence storage, transportation and handling characteristics, and, by extension, feedstock cost and quality. A variety of densification systems are considered for producing a uniform format feedstock commodity for bioenergy applications, including (i) pellet mill, (ii) cuber, (iii) screw extruder, (iv) briquette press, (v) roller press, (vi) tablet press, and (vii) agglomerator. Each of these systems has varying impacts on feedstock chemical and physical properties, and energy consumption. This review discusses the suitability of these densification systems for biomass feedstocks and the impact these systems have on specific energy consumption and end‐product quality. For example, a briquette press is more flexible in terms of feedstock variables where higher moisture content and larger particles are acceptable for making good quality briquettes; or among different densification systems, a screw press consumes the most energy because it not only compresses but also shears and mixes the material. Pre‐treatment options like pre‐heating, grinding, steam explosion, torrefaction, and ammonia fiber explosion (AFEX) can also help to reduce specific energy consumption during densification and improve binding characteristics. Binding behavior can also be improved by adding natural binders, such as proteins, or commercial binders, such as lignosulfonates. The quality of the densified biomass for both domestic and international markets is evaluated using PFI (United States standard) or CEN (European standard). Published in 2011 by John Wiley & Sons, Ltd
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If the singular goal of biomass logistics and the design of biomass feedstock supply systems is to reduce the per-ton supply cost of biomass, these systems may very well develop with ultimate ...unintended consequences of highly variable and reduced quality biomass feedstocks. This paper demonstrates that, due to inherent species variabilities, production conditions and differing harvest, collection and storage practices, this is a very real scenario that biomass producers and suppliers as well as conversion developers should be aware of. Biomass feedstock attributes of ash, carbohydrates, moisture and particle morphology will be discussed. We will also discuss specifications for these attributes, inherent variability of these attributes in biomass feedstocks, and approaches and solutions for reducing variability for improving feedstock quality.
The economic competitiveness of cellulosic ethanol production is highly dependent on feedstock cost, which constitutes 35–50% of the total ethanol production cost, depending on various geographical ...factors and the types of systems used for harvesting, collecting, preprocessing, transporting, and handling the material. Consequently, as the deployment of cellulosic ethanol biorefineries approaches, feedstock cost and availability are the driving factors that influence pioneer biorefinery locations and will largely control the rate at which this industry grows. Initial scenarios were postulated to develop a pioneer dry feedstock supply system design case as a demonstration of the current state of technology. Based on this pioneer design, advanced scenarios were developed to determine key cost barriers, needed supply system improvements, and technology advancements to achieve government and private sector cost targets. Analysis of the pioneer supply system resulted in a delivered feedstock cost to the throat of the pretreatment reactor of $37.00 per dry tonne (2002 $). Pioneer supply systems will start by using current infrastructure and technologies and be individually designed for biorefineries using specific feedstock types and varieties based on local geographic conditions. As the industry develops and cost barriers are addressed, the supply systems will incorporate advanced technologies that will eliminate downstream diversity and provide a uniform, tailored feedstock for multiple biorefineries located in different regions. Published in 2007 by John Wiley & Sons, Ltd.
Many decisions in life involve tradeoffs between two incommensurate options, so that one's choice reveals the values placed on the options. For example, judicial decisions weigh the possibilities of ...false convictions versus false acquittals. Using a signal detection model, this research demonstrate that Americans generally prefer a judicial error value tradeoff that favors relatively more false acquittals, a pattern generally consistent with the “Blackstone ratio” (i.e., 10:1) in legal history. At the same time, there is substantial variation in these error value tradeoffs and several individual difference measures were assessed as potential factors to account for this variation. Contrary to expectations, judicial error value tradeoff preferences were not significantly related to political liberalism/conservatism, individualism/communalism, social dominance orientation, or political party affiliation. There was, however, a significant relationship between greater authoritarianism and preference for less bias to avoid false convictions. A third study replicated this finding and extended the research scope to other error value tradeoff contexts (e.g., in military, immigration, and business regulation settings). Additionally, Study 3 found significant relationships between context-specific attitudes and libertarianism/authoritarianism, liberalism/conservativism, and social dominance orientation for immigration, military, business regulation contexts.
Retrieval practice is a straightforward and effective way to improve student learning, and its efficacy has been demonstrated repeatedly in the laboratory and in the classroom. In the current study, ...we implemented retrieval practice in the form of daily reviews in the classroom. Students (N = 47) in a cognitive psychology course completed a daily review at the beginning of each class. These consisted of 2-4 questions that encouraged students to practice retrieving material covered in lectures from the previous week. Then at the end of the semester, students took a comprehensive final exam consisting of content that was either on a daily review, a unit exam, both or neither. We replicated previous work such that retrieval practice improved memory. Specifically, we found that students performed significantly better on questions whose information had been covered on both a daily review and unit exam. However, student performance did not differ amongst items covered only on a daily review, a unit exam, or on neither. Additionally, we extended previous work and found that students were significantly less overconfident for information covered on both a daily review and unit exam. The current results indicate that retrieval practice helps college students remember material over the course of a semester and also improves their ability to evaluate their own knowledge of the material.
Long-term low cost storage of whole-stalk lignocellulosic energy sorghum biomass (specialized forage varieties of Sorghum bicolor (L.) Moench) is essential for the feedstock's successful role as a ...dedicated energy crop for ethanol production. As an alternative to expensive ensiling methods, aerobic storage of S. bicolor (L.) Moench biomass in traditional rectangular bale formats could alleviate feedstock supply costs if material deterioration in storage could be minimized. Moisture desorption and adsorption isotherms for S. bicolor (L.) Moench were created at 15 °C, 20 °C, 30 °C, and 40 °C with water activities from 0.1 to 0.9 using the dynamic dew-point method. Sorption isotherms were modeled using four temperature dependent and three temperature independent equations. The relationship between equilibrium moisture content and water activity was found to decrease with increasing temperatures. GAB (Guggenheim–Anderson–de Boer) monolayer moisture content and the moisture content at which microbial activity becomes limited were found to range from 5.6% db to 10.4% dry basis (db) and 12.0% db to 18.4% db, respectively. The net isosteric heat of sorption was calculated using the Clausius–Clapeyron equation and determined to be higher for desorption than adsorption with both trends decreasing exponentially at increasing levels of moisture content. The differential entropy of S. bicolor (L.) Moench was shown to exhibit a log normal relationship with moisture; peaking near the monolayer moisture content. The results of the study indicate that aerobic storage of energy sorghum biomass may be similar to other herbaceous feedstocks should extensive drying occur before entering storage.
► Equilibrium moisture content is influenced by temperature and sorption direction. ► Safe aerobic storage moisture levels range from 12.0% to 18.4% dry basis. ► Desorption surface moisture becomes material-bound by approximately 25% dry basis. ► Material swelling at low moisture causes an increase in moisture sorption sites.
Abstract
Objective
Patients with chronic low back pain (CLBP) and comorbid depression or anxiety disorders are highly prevalent. Negative affect (NA) refers to a combination of negative thoughts, ...emotions, and behaviors. Patients with CLBP with high NA have greater pain, worse treatment outcomes, and greater prescription opioid misuse. We present the protocol for SYNNAPTIC (SYNergizing Negative Affect & Pain Treatment In Chronic pain).
Design
A randomized comparative-effectiveness study of antidepressants, fear-avoidance rehabilitation, or their combination in 300 patients with CLBP with high NA. In the antidepressant- or rehabilitation-only arms, SYNNAPTIC includes an adaptive design of re-randomization after 4 months for nonresponders.
Setting
A multisite trial conducted in routine pain clinical treatment settings: pain clinics and physical and occupational therapy treatment centers.
Methods
Inclusion criteria include CLBP with elevated depression and anxiety symptoms. Antidepressant and rehabilitation treatments follow validated and effective protocols for musculoskeletal pain in patients with high NA. Power and sample size are based on superior outcomes of combination therapy with these same treatments in a 71-subject 4-arm pilot randomized controlled trial.
Conclusions
SYNNAPTIC addresses the lack of evidence-based protocols for the treatment of the vulnerable subgroup of patients with CLBP and high NA. We hypothesize that combination therapy of antidepressants plus fear-avoidance rehabilitation will be more effective than each treatment alone.
Trial registration
ClinicalTrials.gov ID: NCT04747314.
A person's ability to work with and understand numerical information (i.e., numeracy) is increasingly important in everyday health and other decision-making contexts. Several survey measures of ...numeracy have been developed to address this trend, including the widely used General Numeracy Scale (GNS), which is thematically focused on health decision-making and is assumed to measure a unidimensional construct of numeracy.
The present research was designed to evaluate this proposed unidimensional structure of general numeracy, for which prior data have given mixed empirical support.
Three samples completed the GNS, in different forms, and responses were analyzed in terms of underlying factor structure.
We show that both one-factor and four-factor models of numeracy are plausible based on the GNS (Study 1), and then develop a multiple-choice version of the GNS (i.e., the MC-GNS) that demonstrates some increased clarity in factor structure due to the consistent response format (Study 2). A further study evaluated the convergent and discriminant validity of the MC-GNS (Study 3), finding it to be as good as or better than the prior scale.
Additionally, the MC-GNS is easier for people to take, likely to be less stressful, and easier for practitioners to score. Collectively, this research identifies a problem with the GNS measure, develops improvements to help address this problem, and in the process creates a way to more easily measure numeracy in practical settings.
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Numeracy is important across health contexts. Prevalent numeracy scales assumedly measure a single construct but empirical support for this is lacking. We find both one- and four-factor models are consistent with one scale and develop a revision that clarifies this structure without sacrificing validity. This revised numeracy scale is easier to administer and score, and therefore preferable in practical settings.
Cost-effective conversion of agricultural residues for renewable energy hinges not only on the material’s quality but also the biorefinery’s ability to reliably measure quality specifications. The ...ash content of biomass is one such specification, influencing pretreatment and disposal costs for the conversion facility and the overall value of a delivered lot of biomass. The biomass harvest process represents a primary pathway for accumulation of soil-derived ash within baled material. In this work, the influence of five collection techniques on the total ash content and variability of ash content within baled corn stover in southwest Kansas is discussed. The equipment tested included a mower for cutting the corn stover stubble, a basket rake, wheel rake, or shred flail to gather the stover, and a mixed or uniform in-feed baler for final collection. The results showed mean ash content to range from 11.5 to 28.2 % depending on operational choice. Resulting impacts on feedstock costs for a biochemical conversion process range from $5.38 to $22.30 Mg⁻¹ based on the loss of convertible dry matter and ash disposal costs. Collection techniques that minimized soil contact (shred flail or nonmowed stubble) were shown to prevent excessive ash contamination, whereas more aggressive techniques (mowing and use of a wheel rake) caused greater soil disturbance and entrainment within the final baled material. Material sampling and testing were shown to become more difficult as within-bale ash variability increased, creating uncertainty around feedstock quality and the associated costs of ash mitigation.
As biorefining conversion technologies become commercial, feedstock availability, supply system logistics, and biomass material attributes are emerging as major barriers to the availability of corn ...stover for biorefining. While systems do exist to supply corn stover as feedstock to biorefining facilities, stover material attributes affecting physical deconstruction, such as densification and post-harvest material stability, challenge the cost-effectiveness of present-day feedstock logistics systems. In addition, the material characteristics of corn stover create barriers with any supply system design in terms of equipment capacity/efficiency, dry matter loss, and capital use efficiency. However, analysis of a conventional large square bale corn stover feedstock supply system concludes that (1) where other agronomic factors are not limiting, corn stover can be accessed and supplied to a biorefinery using existing bale-based technologies, (2) technologies and new supply system designs are necessary to overcome biomass bulk density and moisture material property challenges, and (3) major opportunities to improve conventional bale biomass feedstock supply systems include improvements in equipment efficiency and capacity and reducing biomass losses in harvesting, collection, and storage. Finally, the backbone of an effective stover supply system design is the optimization of intended and minimization of unintended material property changes as the corn stover passes through the individual supply system processes from the field to the biorefinery conversion processes.
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