Investigating impact of pulp density on flotation performance

Dissertation (Ph.D.) University of Alaska Fairbanks, 2022The Red Dog Mine, located in northwest Alaska, is one of the world's largest zinc/lead mines. The processing mill feed consists of a blend of ores from two different pits, namely, the Aqqaluk pit and the Qanaiyaq pit respectively. The mill circuit consists of grinding and multiple flotation circuits which separate zinc and lead minerals from their gangue contents depending on the interfacial tension between hydrophilic/hydrophobic mineral surfaces and their environment. The flotation circuit feed is characterized by high percent solids (~ 50%). Percent solids can potentially have a significant effect on the grade/recovery curve. Thus, it is very common that low-density slurries give better flotation response (high grades), particularly in flotation systems containing a significant amount of liberated hydrophilic unwanted mineral particles. Moreover, the blended feed is metallurgically complex and weathered, thus adversely affecting the performance of the mill. This project investigated the effects of pulp density on Red Dog flotation circuit performance and develop strategies to maximize recovery at 50% solids. Higher solids content increases the rheology of the slurry thereby causing turbulence and froth instability. To study the impacts of slurry density on flotation kinetics, a series of experiments were conducted by varying various operating and process parameters and assessing circuit optimization strategies. Initial batch tests performed on cyclone overflow samples showed that residence time, rotor revolution per minutes (RPM), and slurry density are important factors affecting flotation performance. Lower slurry densities usually lead to better kinetics. However, in the case of the initial tests, results indicated that slurry density has a minimal effect if residence time is increased. It was shown that yields as high as 73% with Lead (Pb) recovery values of 86.20% is possible even at 60% solids concentration by increasing the residence time. If the slurry is sufficiently diluted then higher rotor speeds combined with higher residence time would provide higher yields and recoveries. Initial results indicate that at lower RPM ranges, adequate residence time and higher slurry densities lead to better bubble loading and froth stability. Lead (Pb) and Zinc (Zn) recovery values of 89.42% and 80.33% were achieved at 20% solids and 1800 RPM rotor speed. Future test work includes investigation of froth stability and pulp phase kinetics, statistically, and designed programs to optimize flotation performance in high-density slurries. Several parameters including dosage, and type of collector, pH, the dosage of frother, dosage of depressant, the dosage of activator, type of grinding media, particle size, and bubble size were controlled in the optimization tests. The optimized condition was obtained for both galena, and sphalerite at different solid%. The locked cycle tests were designed based on the Red Dog flotation circuit. At the optimized condition, the grade, and recovery for solid 30% improved by around 0.5%. The optimized condition had a further impact on the flotation performance at a higher solid%. By increasing the solid%, the grade was improved by 1.84%, and 2.24% at galena concentrate for 40%, and 50%, respectively, compared to the normal condition. Recovery was improved for both solid% by less than 1%. The optimized condition increased Zn grade at the flotation circuit by 1%, and recovery by 4% for 40% of solid. In addition, the optimized condition increased grade at the flotation circuit by 5%, and recovery by 4% for 50% of solid.Institute of Northern Engineering and the Department of Mining and Mineral Engineerin

Synthesis and characterization of four new unsymmetrical potentially pentadentate Schiff base ligands and related Zn(II) and Cd(II) complexes

Two thioether diamines 2-(2-aminoethylthio)aniline and 2-(3-aminopropylthio)aniline have been prepared employing a new procedure by reaction of 2-aminothiophenol and N-(2-bromoethyl)phthalimide or N-(3-bromopropyl)phthalimide, respectively. Then two new potentially pentadentate (N2O2S) Schiff base ligands derived from direct condensation between two maintained diamines and 2-hydroxybenzaldehyde or 5-bromo-2-hydroxy benzaldehyde were synthesized. Also, Zn(II) and Cd(II) complexes of Schiff base ligands have been prepared. These compounds have been characterized by physico-chemical and spectroscopic methods

Florid Cemento-Osseous Dysplasia at the Site of Previous Teeth Extraction: Report of a Case

Objective: Florid cemento-osseous dysplasia (FCOD) is a rare bone lesion that predominantly involves the women’s jaws in middle age. This condition is usually asymptomatic and has a benign course.Case: This paper presents a rare case of FCOD in a white middle aged woman, which had affected mandible bilaterally and was diagnosed after tooth extraction and treated conservatively.We believed tooth extraction was a contributing factor for outbreak of such a lesion in this susceptible patient.Conclusion: For the asymptomatic patients, the best management consists of regular recall examinations with prophylaxis and reinforcement of oral hygiene to prevent periodontal diseases and tooth loss, but with accession of clinical signs and symptoms, surgical intervention is inevitable

The Development of Self and Other Forgiveness from Adolescence to Emerging Adulthood

The purpose of this study was to investigate the development of self, others, and situation forgiveness from adolescence to emerging adulthood. To this end, 395 individuals, aged 12 to 25 years in four age groups living in Isfahan, Iran, were selected by cluster (for the first three groups) and available sampling (for the fourth group). The study was a cross-sectional study with using the causal-comparative design and the required data were collected with the Forgiveness Scale. The results of the analysis of variance showed that forgiveness of self had a slight decreasing trend from the beginning of adolescence to adulthood. The results also revealed that forgiveness of others declined from 12 to 16 years of age, however, it increased in emerging adulthood. Moreover, the changes in situation forgiveness were not significant in four groups. Eta squared results showed a small effect of age on the forgiveness of self (2%) and forgiveness of others (4%). Finally, there was no significant gender difference in the forgiveness of self and others in different age groups.Introduction*Forgiveness can be defined as a decision to release negative feelings, cognition, and behaviors based on a sense of sympathy, respect and grievance for guilty (Lavafpour et al., 2014). Neto et al. (2014) pointed out three forms of forgiveness: other, self, and situation forgiveness. Other forgiveness manifests itself in intentionally reducing the negative feelings and thoughts against others. Furthermore, self forgiveness refers to passionately releasing the sense of agony against oneself and conversely improving compassion and love for the self (Enright, 1996). Additionally, situation forgiveness refers to rendering all the negative thoughts and feelings surrounding the inevitable hard situations (Tompson et al., 2005). Chiaramello et al. (2008), in their study of the development of forgiveness in adolescence, found that teenagers in the middle of adolescence were less forgiving and more vindictive than in the beginning. Subkowiak et al. (1995) also found that teenagers usually forgave significantly less than adults in similar situations. After adolescence, forgiveness of others increases with age in adulthood. This is because adolescence is the time of identity formation (Berk, 2007, 2014) and emerging adulthood is the period of identity consolidation (Arnett, 2000; Lotfabadi, 2009). Moreover, different ways of socialization of boys and girls (Dastranj, 2013) may cause gender differences in their forgiveness. As such, it can be concluded that the desire to forgive has a developmental trend. This research study aimed to seek this developmental trend for forgiveness from adolescence to emerging adulthood. MethodThis study employed a cross-sectional study with a causal-comparative design. Its statistical sample included 395 individuals whose aged ranged from 12 to 25 years living in Esfahan, Iran. The group classification was a 12-year-old group (55 girls and 50 boys), a 14-year-old group (49 girls and 51 boys), a 16-year-old group (51 girls and 45 boys), and an 18-23-year-old group (48 girls and 46 boys). They were selected by cluster (for the first three groups) and available sampling (for the fourth group). The data were gathered using the Hartland Forgiveness Scale (2005). Hartland Forgiveness Scale (Thompson et al., 2005) includes 18 items in three subscales (self, other, and situation forgiveness). The items are on a 5-point Likert scale ranging from 1 (the least amount of forgiveness) to 5 (the highest amount of forgiveness). The descriptive indices (mean, standard deviation), independent group t-tests, multivariate analysis of variance, and Tukey's post hoc test were used to analyze the obtained data. ResultsAccording to the multivariate analysis of variance, there was a significant difference between age groups in the forgiveness of self and others. However, the eta squares for both variables were .02 and .04, respectively, which indicates a small effect. Self-forgiveness differed significantly only between the two groups of 12 and 18-25 years old. Self-forgiveness scores decreased among 18-25-year-olds as compared to 12-year-olds (mean diff.=1.31, p = 0.02). Nonetheless, there were significant differences between the three groups in terms of other forgiveness. There was a decrease in other forgiveness between 16-years-old group and to 12-years-old (Mean diff.=1.63, p = 0.05), and there was an increase in forgiveness for the 18-25 years-old and 14 and 16-years-old groups (Mean diff.= -1.686, p=0.05 and Mean diff.= -2.668, p=0.001). Independent t-tests were used to examine gender differences in forgiveness scores for girls and boys in each age group. Only for situation forgiveness among the12-years-old group, the gender difference was significant with an effect size of (η2=0.05, t=2.39, and p=0.01), while no difference was observed in the other groups. In the 12-year-old group, the scores of situation forgiveness were higher for boys than girls. ConclusionThe results showed that other forgiveness decreased during adolescence and reached its lowest level at the age of 16 and after that, in emerging adulthood, other forgiveness increased significantly. The research of Girard and Mallet (2012) and Chiramello et al. (2008) reported the developmental course of forgiveness of others in adolescents until the age of 15. Also, Subkowiak et al. (1995) stated that adolescents were significantly less forgiving than their same-sex parents in similar situations. As expected, the conflict of the emerging adulthood stage of intimacy versus isolation and relationships with others becomes important for the individual; therefore, the person preserves one’s valuable relationships by forgiving others' mistakes (Kaleta & Mróz, 2018). Also, the findings showed that the development of self-forgiveness has a downward slope, and the 18-25-years-old group forgave themselves significantly less than the 12-year-old group. During adolescence, when identity is formed, self-forgiveness does not change much, but with the emergence of self-esteem, self-evaluation takes place, and a person becomes more sensitive about one’s mistakes, and self-forgiveness becomes more difficult and decreases. However, this research study did not find significant changes in situation forgiveness in four groups. Unfortunately, research background focuses on the forgiveness of others, and other dimensions of forgiveness have not been carefully investigated yet. Therefore, there is little evidence to compare the findings of self-forgiveness and situation, especially during adolescence. In addition, some factors such as small effect sizes and low statistical power can limit generalization of the findings of the present study. Ethical Consideration Compliance with Ethical Guidelines: All ethical issues such as informed consent and confidentiality of participants' identity were respected. Authors’ Contributions: All authors contributed to the study. The first author wrote the first draft of the manuscript. The second and third authors edited the manuscript and the second author is corresponding author.Conflict of Interest: The authors declare no conflict of interest for this study. Funding: This study was conducted with no financial support and is part of M.A. thesis of the first author.Acknowledgment: The authors thank all participants in the study. *. Corresponding autho

Prediction of Body Image Dissatisfaction Based on Spiritual Intelligence and Socio-cultural Patterns in Women Attending Gyms in Yazd

Background and Objective: Body image is a multifactorial concept, which is one of the most fundamental concerns for individuals. We aimed to predict body image dissatisfaction based on spiritual intelligence and socio-cultural patterns in women attending gyms in Yazd, Iran. Materials and Methods: This descriptive correlational study was performed among female residents of Yazd who participated sports classes in 2015. Overall, 351 individuals were selected by using the random cluster sampling method. The data collection instruments included Body Image Concern Inventory, as well as spiritual intelligence and socio-cultural patterns questionnaires. To analyze the data, Pearson correlation coefficient and multivariate regression analysis tests were run in SPSS, version 22. Results: We found a negative correlation between spiritual intelligence and body image dissatisfaction. Moreover, there was a significant positive correlation between socio-cultural patterns and body image dissatisfaction (P≤0.05). In addition, both spiritual intelligence and socio -cultural patterns predicted body image dissatisfaction, yet spiritual intelligence was a stronger contributing factor. Conclusion: Results showed that spiritual intelligence and socio-cultural patterns play a significant role in the anticipation of body image dissatisfaction. However, the former is a stronger predictor of body image dissatisfaction as compared to the latter. Therefore, a survey of effectiveness of spiritual intelligence training sessions to reduce body image dissatisfaction is suggested for future research

Determining the opacity of urinary stone using only the Computed Tomography imaging, Is KUB still needed?

Introduction: Defining the opacity of urinary stones by Kidney -Ureter-Bladder (KUB) imaging in the selection of treatment modality is considered necessary by many urologists. This imposes more radiation to patients and additional health costs. The objective of this study is evaluation of the capability of Computed Tomography (CT) imaging in predicting the opacity of urinary calculi. Methods: In this prospective study, the appearance of stones and the body characteristics of all our patients were recorded and analyzed. The setup for reviewing the imaging was as follows: first: CT-scout, then KUB and finally CT scan. The sensitivity and specificity of the CT-scout and Hounsfield unit in detecting stone opacity was calculated. The effect of stone size and body parameters in CT on predicting non-opaque stones were then analyzed. CT scout-negative KUB-positive urolithiasis were analyzed separately. Results: Among 197 participants, all opaque calculi in CT scout were also visible on KUB. Among scout-negative urinary stones, twenty-eight (14.21%) were KUB opaque. For predicting the opacity by CT scan parameters, the most desirable HU cut-off was 504 HU and 510 HU in KUB and CT scout, with 80.8% and 86.5% sensitivity, respectively. The overall sensitivity of CT-scout was 86.27% and specificity was 64.29%. Stone diameter ≥5mm and subcutaneous fat width of ≤25.40 mm augmented the sensitivity in our study groups. Conclusion:  All opaque calculi on scout imaging are also opaque on KUB and this could obviate the necessity of KUB imaging in this group of patients.  HU above 504 in scout-negative stones has the best sensitivity and specificity in foretelling the opacity of stones and size ≥5mm and subcutaneous fat width of ≤25.40 mm augment their predictability potential

The effectiveness of short-term dynamic/interpersonal group therapy on perfectionism; assessment of anxiety, depression and interpersonal problems

Introduction: Perfectionism is acknowledged as a core vulnerability and a perpetuating factor in several psychopathologies. The purpose of the present study was to investigate the effectiveness of short-term dynamic/interpersonal group therapy on perfectionism and perfectionism-related distress such as anxiety, depression, and interpersonal problems. Method: This study is a quasi-experimental study applying clinical trial method and contains pre-test, post-test, follow-up periods and control group. The study population included students and the sample consisted of 30 people with extreme perfectionism, who were assigned in two groups of 15 people, experimental and waiting list groups using randomized block design. Research instruments included TMPS, PSPS, PCI, BDI-II, BAI and IIP-32 scales. In order to analyze the collected data, mixed analysis of variance and Repeated Measures Analysis of Variance were used in SPSS software version 22. Findings: The results show that the intervention in the experimental group compared to the waiting list group caused a clinically and statistically significant decrease in the mean scores. This result is observable and evident in all levels of perfectionism and psychological distress (anxiety, depression and interpersonal problems), except for the subscale of non-display of imperfection from the PSPS scale. These results were preserved through the follow-up periods. Discussion: These results show that short-term dynamic/interpersonal group therapy is effective in treating most of the components of perfectionism, and concerning its effectiveness; it reduced psychological distress and showed that the components pertaining to perfectionism are factors of vulnerability in this regard.

Comparison of Oral Health-Related Quality of Life, Patient Satisfaction, and Stress Level between Patients Undergone Fixed Orthodontic Treatment and Clear Aligner Therapy

Introduction: Few studies were conducted on the effectiveness of clear aligners. The present study aimed to compare the quality of life related to oral health, patient satisfaction, and the level of anxiety caused by treatment in patients treated with fixed orthodontics and clear aligners.Materials and Methods: This descriptive-analytical study was conducted on 100 patients undergoing fixed orthodontic treatment six months from the start of their treatment and 100 patients undergoing treatment with clear aligners six months from the start of their treatment. The Oral Health Impact Profile (OHIP-14) questionnaire was used to compare the effect of these two treatments on the quality of life related to the oral health of these patients. Additionally, Patient Satisfaction (PSQ-18) questionnaire was used to check patients’ satisfaction and State Trait Anxiety Inventory was used to assess patients’ anxiety status.Results: The patients included 78 (38. 8%) males and 122 (61.2%) females. The average quality of life related to oral health was 53.26 with a range of 19 to 69, the average patient satisfaction was 42. 46, with a range of 14 to 50, and the mean and standard deviation of anxiety caused by treatment was 72. 26 ± 13. 93 with a range of 37 to 99. The average anxiety caused by the treatment in the transparent aligners group was significantly higher than the fixed orthodontic group (P<0.001). The average quality of life related to oral health in the transparent aligners group questionnaire was significantly lower than the fixed orthodontic group (P<0.001).Conclusion: The findings of this study showed that the level of anxiety of clear aligners recipients is higher, and their quality of life is lower

Co-Infection Rates between SARS-CoV-2 and RSV in Oropharyngeal, Nasopharyngeal Aspirate and Saliva Samples of COVID-19 Patients, Shiraz, South of Iran

Statement of the Problem: Determining the prevalence of respiratory viruses' coinfection with coronavirus disease 2019 (COVID-19) is essential to defining its true clinical influence.Purpose: This study aimed to evaluate co-infection rates between severe acute respiratory syndrome–related coronavirus 2 (SARS-CoV-2) and respiratory syncytial virus (RSV) in infected patients in Shiraz, south of Iran.Materials and Method: In a cross-sectional descriptive study, oropharyngeal, nasopharyngeal aspirate (NPA), and saliva samples of 50 COVID-19 patients who were referred to Ali-Asghar hospital (Shiraz, Iran) from March to August 2020, were collected. A control group consisted of age and sex-matched healthy participants. The nasopharyngeal and oropharyngeal aspirates were collected by sterile swabs. All cases were hospitalized, and all SARS-CoV-2 patients had a fever and respiratory symptoms. The samples were packed in a vial with 1 mL of transport medium and transported to the Valfagre specialty laboratory, where they were tested for RSV using a real-time polymerase chain reaction (PCR).Results: 100 nasopharyngeal/oropharyngeal aspirates and saliva samples including 50 healthy controls (24 females, 26 males) and 50 COVID-19 patients' samples (27 males and 23 females) were studied. There was no significant difference regarding age as well as gender between both groups (P>0.05). None of the healthy subjects was infected with RSV; however, 5(10%) patients from COVID-19 group were infected with the RSV virus. Chi-square test did not show a significant difference between RSV infection in COVID-19 patients and healthy subjects.Conclusion: The outcome of present research showed that concurrent RSV with COVID 19 infection might be seen in hospitalized patients in Shiraz Southwest of Iran. For more reliable findings, further research on bigger populations, including more pathogens in several places around the country, and considering the severity of symptoms is required