Improving the capabilities of the chemical engineering simulation system (CHESS) computer program

Chemical process simulation programs have become an indispensable tool to chemical engineers in the preparation of heat and material balances, and energy conservation studies. Since the 1960\u27s several dozen process simulators have been developed which are in use today within companies and through computer service bureaus. Due to advances in the areas of unit operation analysis and thermodynamic relations, these programs require periodic modification. This thesis describes the programming modifications made to the Chemical Engineering Simulation System (CHESS) version 2.0, computer program. This undertaking was considered warranted since no improvements have been made to CHESS since its release in 1971. The objective is to produce a version which is more useful to practicing engineers and students than version 2.0. Many features of CHESS were found to be inferior to other simulators such as ChemShare\u27s DESIGN II and SimSci\u27s PROCESS which are considered by many as the industrial standards. The identified deficiencies are (1) lack of an extensive thermodynamics package, (2) simplified treatment of unit operations, (3) components restricted to hydrocarbons, (4) maximum of 20 components per stream, and (5) brief output. The following improvements to CHESS have been made, Producing version 2.1: A new equipment module, COMP, has been added to simulate the operation of a single stage gas compressor. The outlet conditions and power requirement are determined to increase the pressure of a gas stream. The adiabatic and mechanical efficiencies are included in the calculation of power requirement. Multi-stage compressors must be handled as individual stages in series. This new module replaces the compression calculations in the PUMP module which was inflexible and gave incorrect results.PUMP module has been modified to strictly handle the simulation of liquid pumping. The outlet conditions and power requirement to increase the pressure of a liquid stream are determined. The mechanical efficiency of the pump is included in the power requirement. The energy requirement is added to the feed enthalpy to determine the outlet temperature.The Fahrenheit temperature scale is now used in input/output data, replacing Rankine.Petroleum fraction components may be defined by the user. CHESS will automatically calculate all the necessary physical constants from boiling point, density and molecular weight information supplied in the input data. The capability to define non-standard, user defined components has been retained.An additional summary of the mass rates (lbs/hr) of the components in each stream will be printed at the end of the simulation.A summary of seventeen properties including viscosity, thermal conductivity and density for each stream will be printed at the end of the simulation.Heat release curves (temperature v.s. enthalpy) for specified temperature and pressure limits can be calculated for a maximum of five streams in the simulation. Use of version 2.1 of CHESS provides more useful and practical information about the process and additional simulation capabilities than version 2.0. Compressors and pumps may now be simulated in a more realistic manner using the new COMP and PUMP modules. The calculation of heating/cooling curves provides useful information for the design of heat exchangers (e.g., reboilers and condensers). The stream properties summary provides all the necessary physical properties for equipment design and specification. In addition, the specification of petroleum fraction components in the input data has been simplified. It is recommended that further improvements be made to CHESS in the areas of unit operations and thermodynamics in future work

Associations of Psychological Inflexibility with Exercise Self-Efficacy and Fatigue Severity among Individuals Seeking Treatment for Weight-Related Behaviors

Rates of obesity are continuing to rise, contributing to several negative health outcomes and economic burden. Past work suggests that individuals with greater body mass index (BMI) are more likely to report feeling fatigue and are less likely to follow an exercise regimen, which may lead to weight-related problems. Psychological inflexibility, a rigid thinking style in which individuals attempt to over-control psychological reactions to discomfort, may be an underrecognized explanatory factor underlying greater fatigue and lower rates of exercise among individuals with weight-related concerns. The aim of the current study was to explore the relationship between psychological inflexibility and both exercise self-efficacy and fatigue severity among adults seeking treatment for weight-related behaviors. The current study is a secondary analysis and included 162 treatment-seeking adults who attended a baseline appointment for a larger randomized-controlled trial for weight-related behaviors. Results indicated that greater psychological inflexibility was significantly related to greater fatigue severity and lower exercise self-efficacy. These results provide initial empirical evidence that psychological inflexibility may be an important individual difference factor in terms of fatigue and exercise beliefs among adults seeking treatment for weight-related behaviors

The Association Between Body Mass Index and Anxious Arousal, Depressive, and Insomnia Symptoms Among World Trade Center Responders

Elevations in body mass index (BMI) among World Trade Center (WTC) responders may be associated with poor mental health outcomes. The current study examined the association of BMI with anxious arousal, depressive, and insomnia symptoms among this group. Participants were 412 WTC responders (89.4% male, Mage = 55.3 years, SD = 8.66) who completed health monitoring assessments (self-report and objective) as part of the Long Island site of the WTC Health Program (LI-WTC-HP). Results suggested BMI was statistically significant only in relation to anxious arousal (sr2 = .02, p = .008), after accounting for age and sex. The current study suggests that weight management programs may aid in promoting additional benefits for WTC responders by reducing anxious arousal symptoms as a function of reduced BMI

Anxiety Sensitivity and Fast-Food Ordering Habits Among Black Adults

Black adults experience high rates of overweight/obesity, which is linked to chronic diseases and is exacerbated by fast-food consumption. Anxiety sensitivity, a relative stable fear of anxiety-related sensations, has been linked to high caloric intake. Here, we examine whether anxiety sensitivity is associated with fast-food ordering habits within a convenience sample of black adults. Of 124 adults (79.4% women; Mage = 49.3±11.6; 84.8% overweight/obese), 107 (86.3%) reported eating from a fast-food restaurant in the last month. Participants completed the Anxiety Sensitivity-Index 3, which has a total score and physical, cognitive, and social concerns subscales. Investigator-generated items queried frequency of ordering “supersized” quantities of fast-food (e.g., cheeseburgers, fries), and healthy items (e.g., salads, oatmeal, yogurt), respectively, from “never” to “always.” Covariate-adjusted ordinal logistic regression models were used to assess relations between measures of interest. Anxiety sensitivity (total and physical concerns) was associated with greater odds of more frequently ordering supersized unhealthy fast-food; and anxiety sensitivity (total and cognitive concerns) was associated with lower odds of more frequently ordering healthy items from fast-food restaurants. Results suggest that adults with greater anxiety sensitivity may engage in fast-food ordering habits that can contribute to the overweight/obesity epidemic. Future studies should replicate results and determine the potential for anxiety sensitivity-reduction interventions to affect dietary choices that contribute to overweight/obesity

The interaction of depressive symptoms and hazardous drinking in relation to tobacco craving among treatment seeking depressed smokers: Sex differences

Objectives: The present study sought to address whether there is sex effect in the interactive effect between depressive symptoms and hazardous drinking in the prediction of smoking craving after cognitive-behavioral smoking cessation treatment among those with at least mild depression. Methods: Participants (n=114, mean age 42.0, SD=9.73, 64% women) were treatment-seeking smokers who attended 6 weekly 1-hour sessions involving psychological treatment for cessation. Participants reported depressive symptoms and alcohol use at baseline and reported craving at baseline and after treatment. Results: Results indicated that there was a statistically significant 3-way interaction (depression by alcohol use by sex) for smoking craving (B=-0.30, standard error [SE]=0.14, P=0.042) and appetitive craving (B=-.21, SE=0.09, P=0.031), but not negative reinforcement craving. The form of the significant interactions indicted that higher levels of depressive symptoms and alcohol use were related to greater levels of craving at the end of treatment only among men. Conclusions: The current findings provide novel empirical evidence suggesting that there is a clinically relevant interplay between depressive symptoms and alcohol use regarding general craving and appetitive craving among male treatment-seeking smokers. Although the present results should be replicated in larger samples, this type of research can inform the development of sex-specific interventions for smoking cessation

Cigarette smoking, nicotine dependence and anxiety disorders : a systematic review of population-based, epidemiological studies

Background Multiple studies have demonstrated that rates of smoking and nicotine dependence are increased in individuals with anxiety disorders. However, significant variability exists in the epidemiological literature exploring this relationship, including study design (cross-sectional versus prospective), the population assessed (random sample versus clinical population) and diagnostic instrument utilized.Methods We undertook a systematic review of population-based observational studies that utilized recognized structured clinical diagnostic criteria (Diagnostic and Statistical Manual of Mental Disorders (DSM) or International Classification of Diseases (ICD)) for anxiety disorder diagnosis to investigate the relationship between cigarette smoking, nicotine dependence and anxiety disorders.Results In total, 47 studies met the predefined inclusion criteria, with 12 studies providing prospective information and 5 studies providing quasiprospective information. The available evidence suggests that some baseline anxiety disorders are a risk factor for initiation of smoking and nicotine dependence, although the evidence is heterogeneous and many studies did not control for the effect of comorbid substance use disorders. The identified evidence however appeared to more consistently support cigarette smoking and nicotine dependence as being a risk factor for development of some anxiety disorders (for example, panic disorder, generalized anxiety disorder), although these findings were not replicated in all studies. A number of inconsistencies in the literature were identified.Conclusions Although many studies have demonstrated increased rates of smoking and nicotine dependence in individuals with anxiety disorders, there is a limited and heterogeneous literature that has prospectively examined this relationship in population studies using validated diagnostic criteria. The most consistent evidence supports smoking and nicotine dependence as increasing the risk of panic disorder and generalized anxiety disorder. The literature assessing anxiety disorders increasing smoking and nicotine dependence is inconsistent. Potential issues with the current literature are discussed and directions for future research are suggested

The mediating roles of coping, sleep, and anxiety motives in cannabis use and problems among returning veterans with PTSD and MDD.

Veterans with posttraumatic stress disorder (PTSD) and major depressive disorder (MDD), the two most prevalent mental health disorders in the Iraq and Afghanistan veterans, are at increased risk for cannabis use and problems including cannabis use disorder (CUD). The present study examined the relationship of PTSD and MDD with cannabis use frequency, cannabis problems, and CUD as well as the role of three coping-oriented cannabis use motives (coping with negative affect, situational anxiety, and sleep) that might underlie this relationship. Participants were veterans (N = 301) deployed post 9/11/2001 recruited from Veterans Health Administration facility in the Northeast US based on self-reported lifetime cannabis use. There were strong unique associations between PTSD and MDD and cannabis use frequency, cannabis problems, and CUD. Mediation analyses revealed the three motives accounted, in part, for the relationship between PTSD and MDD with three outcomes in all cases but for PTSD with cannabis problems. When modeled concurrently, sleep motives, but not situational anxiety or coping with negative affect motives, significantly mediated the association between PTSD and MDD with use. Together with coping motives, sleep motives also fully mediated the effects of PTSD and MDD on CUD and in part the effect of MDD on cannabis problems. Findings indicate the important role of certain motives for better understanding the relation between PTSD and MDD with cannabis use and misuse. Future work is needed to explore the clinical utility in targeting specific cannabis use motives in the context of clinical care for mental health and CUD

Linkages between Cigarette Smoking Outcome Expectancies and Negative Emotional Vulnerability

The present investigation examined whether smoking outcome expectancies, as measured by the Smoking Consequences Questionnaire (SCQ; [Brandon, T.H., & Baker, T.B., (1991). The Smoking Consequences Questionnaire: The subjective expected utility of smoking in college students. Psychological Assessment, 3, 484–491.]), were incrementally related to emotional vulnerability factors among an adult sample of 202 daily cigarette smokers (44.6% women; Mage= 23.78 years, SD = 9.69 years). After controlling for cigarettes smoked/day, past 30-day marijuana use, current alcohol consumption, and coping style, negative reinforcement/negative affect reduction outcome expectancies were significantly associated with greater levels of negative affectivity, emotional dysregulation, and anxiety sensitivity. The observed effects for negative reinforcement/negative affect reduction also were independent of shared variance with other outcome expectancies. Negative personal consequences outcome expectancies were significantly and incrementally related to anxiety sensitivity, but not negative affectivity or emotional dysregulation. Findings are discussed in terms of the role of negative reinforcement/ negative affect reduction smoking outcome expectancies and clinically-relevant negative emotional vulnerability for better understanding cigarette smoking-negative mood problem