Using of versine and sagitta calculations for log sawing optimization, part 1: Circular cross-section

Log sawing can be defined as a problem with obtaining squares from a cylindrical shaped raw material, log. There are traditional sawing methods such as live, cant, quarter, etc. for sawmills. However, they cant generally obtain maximum yield due to log and lumber variables for each log. Therefore, many mathematical approaches and computer programs were improved for log sawing. In this study, suitability of two geometrical calculations, versine and sagitta, were tried for log sawing process. Logs were assumed having cylindrical shape and circular cross section. The estimation accuracy of calculations were tested for live and cant sawing methods with in a drawing software. The results showed that one of versine equations works almost as well as the real dimensions. It is suggested that the equation can be used inside of algorithms for log sawing optimization. However, the real log defects such as taper, irregular cross-section, curvature, etc. should be considered for more realistic yield and accuracy

Why are European Countries Reluctant to Accept Syrian Refugees?

The conflict in Syria has forcibly moved about 10 million people from their homes. About 5 million of these displaced people fled to four of Syria’s neighbor countries: Turkey, Jordan, Lebanon, and Iraq. Resettlement of Syrian refugees has become a significant public policy debate not only in the neighboring countries of Syria but also in Europe and the United States. Despite the fact that European countries are champions of international law and human rights, there is a strong resistance to acceptance of Syrian refugees. This study analyzes and attempts to explain the reasons why European governments are reluctant to receive Syrian refugees. Several scholars addressed economic and security issues in answering this question. To some, the resettlement of refugees in Europe will create extra burden on already debilitating European economies. To others, the receiving of Syrian refugees increase the threat of terrorism in Europe. Economic and security arguments do not capture the underlying causes of anti-refugee stance among the European policymakers. I argue that domestic political considerations stemming from the increasing Islamophobia and the rise of far right are the main motives behind anti-refugee policies in Europe. Under the pressure of significantly evolving anti-Muslim sentiment particularly after the recent terror attacks in Europe, the European leaders find it gradually difficult to resettle the Syrian refugees without significantly losing public support to their political party platforms

Collapsing Scale Categories: Comparing the Psychometric Properties of Resulting Scales

This study compares a scale, the Rosenberg Self-Esteem Scale, that was administered with four response categories to versions of the same scale that were administered with six and eight response categories. Respondents were randomly assigned to take one of the three versions of RSES. A rating scale utility analysis was conducted on all three versions creating two new four-category versions after collapsing (or combining) adjacent categories. The three different four-category versions were compared on such properties as average scores, correlations with external variables, and factor structure. While most of the psychometric properties were similar across all versions, there were moderate differences related to criterion validity: the scale that did not need to be collapsed had the strongest relationship with external variables, even though there were slightly stronger correlations for the collapsed versions compared to their original scales. A recommendation is made that if it is found that too many categories are being used for a scale then new administrations of the scale should also use the new format, however, an argument could be made to continue administering the survey in its original format, but then collapse responses before analysis

Identifying the Predictors of Mathematics Anxiety AND Performance in Canada: An Educational Data Mining Approach

Over the last decade, Canadian students have exhibited insubstantial improvements in mathematical scores compared to other countries as indicated by large-scale educational assessments such as the Programme for International Student Assessment (PISA) and the Trends in International Mathematics and Science Study (TIMSS). In relation to students’ mathematical performance, math anxiety - the feeling of fear or nervousness when performing math-related tasks - was found as an associated factor. However, no previous study has explored math performance and math anxiety, specifically among Albertan students. We present a work-in-progress that identifies significant predictors of math performance and math anxiety among Canadian and Albertan students, using the PISA 2018 and TIMSS 2019 datasets. This study has three phases: first, a list of predictors will be selected from the data set based on existing theories regarding students’ math performance and math anxiety. The initial list of predictors will be presented to domain experts (i.e., math teachers) for refinement based on their practical experience. A predictive model for math performance and math anxiety will be developed with Educational Data Mining techniques in the second phase. Results from the model will be presented to the domain experts for their inputs as the qualitative component, and variable importance metrics of the model will be consulted for the quantitative component. Findings from both components will be integrated consulted with the domain experts to derive actionable recommendations that would inform various stakeholders (e.g., educators, school districts, and Alberta Education) of ways to improve math performance in Alberta students

Feature Embedding by Template Matching as a ResNet Block

Convolution blocks serve as local feature extractors and are the key to success of the neural networks. To make local semantic feature embedding rather explicit, we reformulate convolution blocks as feature selection according to the best matching kernel. In this manner, we show that typical ResNet blocks indeed perform local feature embedding via template matching once batch normalization (BN) followed by a rectified linear unit (ReLU) is interpreted as arg-max optimizer. Following this perspective, we tailor a residual block that explicitly forces semantically meaningful local feature embedding through using label information. Specifically, we assign a feature vector to each local region according to the classes that the corresponding region matches. We evaluate our method on three popular benchmark datasets with several architectures for image classification and consistently show that our approach substantially improves the performance of the baseline architectures.Comment: Accepted at the British Machine Vision Conference 2022 (BMVC 2022

Ispitivanje parametara površinske kvalitete toplinski prešanog drva paulovnije

The aim of this study was to evaluate the effect of thermal compression process on some surface properties of paulownia solid wood materials. The widest surface of wood samples was mechanically compressed at high temperatures. The duration was 45 min. Four different process combinations were created, including two temperatures (150 °C and 170 °C) and two pressure levels (20 bar and 22.5 bar). The surface roughness, wettability and color properties of treated and untreated samples were compared. The roughness properties, both parallel and perpendicular to grain direction, were determined according to JIS B 0601:1994 standard. The contact angle changes of water dripped to the surface were measured according to time. For color properties, a spectrophotometer was used according to CIE L*a*b* system. The color changes were classified according to a grading method from literature. The most remarkable results on wettability were observed. The contact angle values significantly increased with this method. Although higher temperature increased the contact angle values, higher pressures did not change the values. When the surface roughness values were generally considered, this technique could decrease the values up to 40 % ratio according to the control group. Only the combination of 150 °C and 20 bar did not significantly change the values. Lastly, the results of color properties showed that all treatment parameters significantly affected total color change values of samples. Grading results were similar and the color change of modified samples graded as the lowest color difference, except with the combination of 150 °C and 20 bar. The combination of 170 °C and 22.5 bar (highest treatment conditions) significantly changed all color characteristics of samples, except b* parameter. The results of this research showed that mechanical thermal compression method could change surface properties of this fast-growing species.Cilj ovog rada bio je procijeniti učinak toplinskog prešanja na neka površinska svojstva drva paulovnije. Najveća površina uzoraka bila je prešana pri visokim temperaturama. Prešanje je trajalo 45 minuta. Primijenjene su četiri različite kombinacije uvjeta prešanja, uključujući dvije vrijednosti temperature (150 i 170 °C) i dva različita tlaka (20 i 22,5 bara). U eksperimentu su uspoređeni hrapavost površine, kvašenje i boja prešanih i neprešanih uzoraka. Hrapavost je mjerena paralelno i okomito na smjer vlakanaca prema normi JIS B 0601:1994. Mjerena je i promjena kontaktnog kuta vode na površini u vremenu. Boja je određivana spektrofotometrom prema sustavu CIE L*a*b*. Promjene boje klasificirane su primjenom klasifikacijske metode iz literature. Najveće su promjene primijećene među vrijednostima kvašenja. Vrijednosti kontaktnog kuta značajno su se povećale prešanjem. Iako je viša temperatura utjecala na povećanje vrijednosti kontaktnog kuta, veći tlakovi nisu promijenili vrijednosti kontaktnog kuta. Ako se općenito uzmu u obzir vrijednosti hrapavosti površine, upotrijebljena bi tehnika prešanja mogla smanjiti vrijednosti hrapavosti do 40 % s obzirom na kontrolne uzorke. Samo kombinacija od 150 °C i 20 bara nije znatnije promijenila ispitivane vrijednosti. Glede boje, rezultati su pokazali da su svi parametri prešanja bitno utjecali na ukupne vrijednosti promjene boje uzoraka. Rezultati ocjenjivanja boje bili su slični, a promjene boje prešanih uzoraka ocijenjene su kao najmanje, osim za kombinaciju 150 °C i 20 bara. Pogotovo je kombinacija 170 °C i 22,5 bara (najviši parametri prešanja) značajno promijenila sve parametre boje uzoraka, osim parametra b*. Rezultati ovog istraživanja pokazali su da bi metoda toplinskog prešanja mogla promijeniti površinska svojstva drva ove brzorastuće vrste

A study of brush seal porous media resistance coefficients

Developments in turbine technologies lead to higher operating temperature and pressure conditions. Parasitic leakage flows around the turbine account for considerable efficiency losses that increase fuel cost dramatically. Brush seal has recently emerged as an improved sealing technology to provide better leakage performance and to replace classical labyrinth seals. In order to optimize efficiency, comprehensive study of the factors causing the leakage is required. The leakage performance of the brush seal is directly related with geometry, operating inlet and outlet boundary conditions, bristle pack configuration. Brush seal flow and pressure profiles with turbine operating conditions become complicated, and analytical formulations remain inadequate to correlate design parameters and leakage performance in operating conditions. Recently brush seals have found ever increasing applications in steam turbines. Literature review indicates that there is very limited studies of brush seal for steam environment. There is also no correlation available for brush seal porosity coefficients in the literature. In an attempt to meet this need, six brush seals have been tested in a rotary test rig up to 100 psi upstream pressure. Analytical correlations and CFD (Computational Fluid Dynamics) simulations have been performed for test seals and results have been correlated with the test data. Axisymmetric CFD models have been designed to reach anisotropic resistance coefficients for the brush seals based on experiments. Porous Medium Approach has been applied for representing bristle pack. Leakage rate of brush seals (steam environment) has been optimized through CFD models. Moreover, velocity and pressure characteristics in the bristle pack have been illustrated for an optimum solutions. Consequently, empirical correlations for brush seal porosity coefficients have been correlated through a systematic methodology

The effects of IL-10 gene polymorphism on serum, and gingival crevicular fluid levels of IL-6 and IL-10 in chronic periodontitis

Objective Anti-inflammatory cytokines play a crucial role in periodontitis by inhibiting synthesis of pro-inflammatory cytokines. The purpose of this study was to evaluate the effect of interleukin-10 (-597) gene polymorphism and genotype distributions on chronic periodontitis (CP) development and IL-6 and IL-10 levels in gingival crevicular fluid (GCF) and serum before and after non-surgical periodontal treatment. Material and Methods The study population consisted of 55 severe generalized CP patients as CP group and 50 healthy individuals as control group. Plaque index, gingival index, probing depth and clinical attachment level were recorded and GCF and blood samples were taken at both the baseline and the sixth week after non-surgical periodontal treatment. PCR-RFLP procedure was used for gene analyses and cytokine levels were measured via ELISA. Results IL-10 genotype distribution was significantly different between CP and control groups (p=0.000, OR:7, 95%CI, 2.83-60.25). Clinical measurements significantly improved in the CP group after periodontal treatment (p;0.05). Sixth week GCF IL-10 levels were significantly lower in patients carrying IL-10 AC+CC genotype compared to the patients carrying IL-10 AA genotype (p;0.05). Conclusion IL-10 AA genotype carriers had lower IL-6 and IL-6/10 levels in serum; however, GCF IL-6/10 levels were similar in both genotypes. Within the limitations of our study, a possible association between IL-10(-597) gene polymorphism and CP might be considered

3D FEM comparison of lingual and labial orthodontics in en masse retraction

BACKGROUND: The aim of this study was to compare displacements and stress after en masse retraction of mandibular dentition with lingual and labial orthodontics using three-dimensional (3D) finite element models (FEM).METHODS: A 3D FEM of each lower tooth was constructed and located as appropriate to Roth's prescription. The 0.018-in. GAC Roth Ovation labial and Ormco 7th Generation lingual brackets were virtually bonded to the lower teeth and threaded with 0.018 × 0.025- and 0.016 × 0.022-in. SS labial (Tru-Arch form, small size) and lingual (mushroom) archwires. En masse retraction was simulated by applying 300 g of distal force from the canine to the second premolar on the 0.016 × 0.022-in. SS labial and lingual archwires. The type of finite element used in the analysis was an eight-noded brick element. The Algor program (Algor Inc., Pittsburgh, PA, USA) was used to calculate the strains and displacements at each nodal point.RESULTS: Lingual tipping and extrusion of the anterior dentition occurred with both archwires. At the premolars and first molars, intrusion, lingual movements, and lingual tipping were seen with the labial archwire, while intrusion was accompanied by labial movements, mesial tipping, and buccal rotation with lingual mechanics.CONCLUSIONS: Lingual vs. labial bracket placement influences the pattern of tooth movement, but the stress that occurs around the teeth can be accurately mapped using a 3D FEM model

Comparison of Oral Hygiene Attitudes, Awareness and Periodontal Parameters of Undergraduate Dental Students

Objectives:  The aim of this study was to compare the differences in self-reported oral health attitudes and clinical measurements between dental students who enrolled in or not enrolled in periodontology course in Turkey. Material and Methods: A total of 701 students were included in the study. Students asked 26 questions including age, gender, smoking, oral hygiene habits and self-assessment measures for periodontal status. Probing depth (PD) clinical attachment level (CAL), presence of bleeding on probing (BOP), plaque index (PI) and gingival index (GI) measurements performed. The Chi-square test was used for categorical data and one way Anova post hoc Tukey test for ordinal level data. Results: There were no differences between grades in term of PD and CAL (p>0.05). Statistically significant difference was in BOP value between 1st and 5th grade (p<0.05). PI values of 1st grade were statistically higher than 3rd, 4th and 5th grades (p<0.05).  GI of 1st grade was statistically higher than 4th and 5th grades (p<0.05). GI of 2nd grade was statistically higher than 3rd, 4th and 5th grades (p<0.05). Tooth brushing was not different between grades (p>0.05). Interdental care ratios in grades significantly differ from each other (p<0.05). According to students, they did not have any kind of periodontal disease with high percentages above 88%.  4th and 5th grades had periodontal treatment comparing the other grades (p<0.05). Conclusion: Starting to take periodontology course in dental faculties from the first year and constitute a periodontal disease prevention program will be beneficial to students in Turkey