scholarly journals Geometric morphometrics reveal relationship between cut-mark morphology and cutting tools

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 109
Author(s):  
Francesco Boschin ◽  
Erika Moretti ◽  
Jacopo Crezzini ◽  
Simona Arrighi

The analysis of bone-surface modifications (BSM), such as butchering marks, is necessary to better understand how the exploitation of animal resources by past hominins influenced their biological and cultural evolution. In this paper, we try to quantify to what extent the depth of the cut marks influences the shape of their cross sections. This is of crucial importance for a valid interpretation of the shape data collected on archaeological BSMs. Two groups of slicing cut-mark cross sections were experimentally produced with two flint burins on a defleshed cattle innominate, and a set of butchering marks were produced with an unretouched flint flake. These were analysed by means of 3D microscopy and geometric morphometrics. The resulting sets of striae show different depths and different cross-sectional shapes. Shallower cross sections display less steep walls and, consequently, a wider opening angle. When the characteristics of the burin cutting edges were investigated, it was clear that the difference in shape between the two groups of striations was probably a function of the way in which the tool penetrated the bone. These results are taphonomically relevant since similar differences in cross-sectional shapes have been found in marks produced with different tools.

2012 ◽  
Vol 7 (1) ◽  
pp. 155892501200700 ◽  
Author(s):  
Yan Wan ◽  
Li Yao ◽  
Bugao Xu

In a microscopic image, fiber cross sections are often surrounded by borders distinctively darker than their bodies and the background. Fiber borders can be utilized to separate cross-sections properly so that accurate fiber shape and size information can be obtained. Hence, locating correct fiber borders is one of the most critical steps in cross-sectional analysis for fiber characterization and identification. This paper introduces a dual-thresholding algorithm that performs automatic fiber border segmentation from noisy cross-sectional images. The dual thresholds include a low threshold calculated based on the histogram of the difference from the average grayscale, and a high threshold computed by a bisection algorithm. With the low threshold, part of fiber border pixels, regarded as seeds, can be reliably located. The seeds can be further expanded by using the high threshold to form complete borders surrounding individual cross-sections. The experimental results show that the dual-thresholding algorithm can obtain cleaner and more fiber borders than other connectional thresholding algorithms, and improves the detection accuracy from 52.78% and 88.88%.


Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2073
Author(s):  
Weiwei Huang ◽  
Yueyi Li ◽  
Karl J. Niklas ◽  
Johan Gielis ◽  
Yongyan Ding ◽  
...  

Many cross-sectional shapes of plants have been found to approximate a superellipse rather than an ellipse. Square bamboos, belonging to the genus Chimonobambusa (Poaceae), are a group of plants with round-edged square-like culm cross sections. The initial application of superellipses to model these culm cross sections has focused on Chimonobambusa quadrangularis (Franceschi) Makino. However, there is a need for large scale empirical data to confirm this hypothesis. In this study, approximately 750 cross sections from 30 culms of C. utilis were scanned to obtain cross-sectional boundary coordinates. A superellipse exhibits a centrosymmetry, but in nature the cross sections of culms usually deviate from a standard circle, ellipse, or superellipse because of the influences of the environment and terrain, resulting in different bending and torsion forces during growth. Thus, more natural cross-sectional shapes appear to have the form of a deformed superellipse. The superellipse equation with a deformation parameter (SEDP) was used to fit boundary data. We find that the cross-sectional shapes (including outer and inner rings) of C. utilis can be well described by SEDP. The adjusted root-mean-square error of SEDP is smaller than that of the superellipse equation without a deformation parameter. A major finding is that the cross-sectional shapes can be divided into two types of superellipse curves: hyperellipses and hypoellipses, even for cross sections from the same culm. There are two proportional relationships between ring area and the product of ring length and width for both the outer and inner rings. The proportionality coefficients are significantly different, as a consequence of the two different superellipse types (i.e., hyperellipses and hypoellipses). The difference in the proportionality coefficients between hyperellipses and hypoellipses for outer rings is greater than that for inner rings. This work informs our understanding and quantifying of the longitudinal deformation of plant stems for future studies to assess the influences of the environment on stem development. This work is also informative for understanding the deviation of natural shapes from a strict rotational symmetry.


Author(s):  
В.И. Сероштан ◽  
П.В. Витчук ◽  
В.Ю. Анцев ◽  
Н.А. Витчук

Oднорогие грузовые крюки грузоподъемных кранов изготавливают способом горячей штамповки и свободной ковки. Действующим стандартом предусмотрено 26 типоразмеров заготовок грузовых крюков. Очевидно, что номенклатура стандартных однорогих грузовых крюков ограничена и не может удовлетворить всего многообразия требований при создании специальных грузоподъемных машин для конкретных условий. В случае применения нестандартных крюков или при нестандартной грузоподъемности крана проводится поверочный расчет крюка. В существующем упрощенном методе расчета однорогих грузовых крюков сечения крюка заменяют правильной трапецией без учета скруглений. Поэтому предложен уточненный метод расчета нестандартных однорогих крюков грузоподъемных кранов. Осуществлена проверка предлагаемого метода при помощи SolidWorks, доказана его точность. Проведен сравнительный анализ результатов вычислений по предлагаемому и существующему упрощенному методам. Сравнение расчетных площадей сечений грузовых крюков, полученных предлагаемым и упрощенным методами, показывает, что разница между ними для стандартных крюков колеблется в пределах 6-10%. В среднем площадь сечения крюка, полученная по предлагаемому уточненному расчету, меньше, чем по упрощенному на 8%. Результаты расчета точной площади поперечного сечения грузового крюка и полученные на их основе значения напряжений в опасных сечениях позволяют на стадии проектирования достичь оптимальной формы грузового крюка. Это позволит в процессе производства получить наименьшее значение металлоемкости грузового крюка, что положительно скажется на его себестоимости Load single-hooks for cranes are made by hot stamping and free forging. The current standard provides for 26 standard sizes of cargo hook blanks. Obviously, the range of standard single-horned cargo hooks is limited and cannot satisfy the whole variety of requirements when creating special lifting machines for specific conditions. In the case of using non-standard hooks or with non-standard crane lifting capacity, a verification calculation of the hook is carried out. In the existing simplified method for calculating one-horned load hooks, the cross-sections of the hook are replaced with a regular trapezoid without taking into account the fillets. Therefore, we propose a refined method for calculating non-standard single-horned hooks of hoisting cranes. We tested the method using SolidWorks and proved its accuracy. We carried out a comparative analysis of the results of calculations by the proposed and existing simplified methods. Comparison of the calculated cross-sectional areas of cargo hooks obtained by the proposed and simplified methods shows that the difference between them for standard hooks ranges from 6-10%. On average, the cross-sectional area ofthe hook, obtained according to the proposed refined calculation, is less than the simplified one by 8%. The results of calculating the exact cross-sectional area of the load hook and the values of stresses in dangerous sections obtained on their basis allow one at the design stage to achieve the optimal shape of the load hook. This will allow one in the production process to obtain the smallest value of the metal consumption of the cargo hook, which will have a positive effect on its cost


Author(s):  
Tak-Ming Chan ◽  
Jiong-Yi Zhu

This paper presents a comparative investigation on the load capacity of octagonal concrete filled steel tubes (CFST) with that of the commonly used circular and square CFST. Existing experimental data of octagonal CFST were collected and based on the cross-sectional properties of the existing octagonal specimens, the corresponding circular and square cross-section were generated under three different control parameters: total cross-sectional area of column, confinement ratio and axial stiffness. Those circular and square cross-sections were used in the numerical analysis of CFST to obtain the load capacity for the comparative investigation. Validated finite element models were built for the modeling of the circular and square CFST. The outcome of comparison shows that the confinement ratio is the crucial parameter to the difference of axial behaviour between octagonal and circular CFST. Under the same confinement ratio, octagonal CFST has a very close axial bearing performance to that in circular CFST and are much better than the square CFST.


Author(s):  
T.B. Ball ◽  
W.M. Hess

It has been demonstrated that cross sections of bundles of hair can be effectively studied using image analysis. These studies can help to elucidate morphological differences of hair from one region of the body to another. The purpose of the present investigation was to use image analysis to determine whether morphological differences could be demonstrated between male and female human Caucasian terminal scalp hair.Hair samples were taken from the back of the head from 18 caucasoid males and 13 caucasoid females (Figs. 1-2). Bundles of 50 hairs were processed for cross-sectional examination and then analyzed using Prism Image Analysis software on a Macintosh llci computer. Twenty morphological parameters of size and shape were evaluated for each hair cross-section. The size parameters evaluated were area, convex area, perimeter, convex perimeter, length, breadth, fiber length, width, equivalent diameter, and inscribed radius. The shape parameters considered were formfactor, roundness, convexity, solidity, compactness, aspect ratio, elongation, curl, and fractal dimension.


2017 ◽  
Vol 8 (1) ◽  
pp. 10
Author(s):  
Narendra Kumar Singh ◽  
Nishant Goyal

Background: Schizophrenia is associated with a high familial, social and economic burden. Schizophrenia is also associated with a high level of disability which may create impediments on the social and economic areas of the patients as well as on their respective family networks. Families with schizophrenia may encounter problems such as impairment of health and well being of other family members, restriction of social activities of the family members and shrinking of support from the social network. Aims: The present study examined the difference in perceived social support and burden of care between the male and female caregivers of patients with schizophrenia. Methods: This was a cross-sectional study examining the difference in perceived social support and burden of care between the male and female caregivers of patients with schizophrenia. The sample consisted of 60 (30 male and 30 female) caregivers of the patients with the diagnosis of schizophrenia as per ICD-10-DCR. Results and Conclusion: This study revealed that male caregivers perceived more social support and less burden of care as compared to female caregivers. Key words: Gender, social support, burden


2018 ◽  
Vol 1 (2) ◽  
pp. 114
Author(s):  
Wahdaniah Wahdaniah ◽  
Sri Tumpuk

Abstract: Routine blood examination is the earliest blood test or screening test to determine the diagnosis of an abnormality. Blood easily froze if it is outside the body and can be prevented by the addition of anticoagulants, one of which Ethylene Diamine Tetra Acetate (EDTA). Currently available vacuum tubes containing EDTA anticoagulants in the form of K2EDTA and K3EDTA. K3EDTA is usually a salt that has better stability than other EDTA salts because it shows a pH approaching a blood pH of about 6.4. The purpose of this research is to know the difference of erythrocyte index results include MCH, MCV and MCHC using K3EDTA anticoagulant with K2EDTA. This research is a cross sectional design. This study used venous blood samples mixed with K2EDTA anticoagulant and venous blood mixed with K3EDTA anticoagulants, each of 30 samples. Data were collected and analyzed using paired different test. Based on data analysis that has been done on MCH examination, p value <0,05 then there is a significant difference between samples with K3EDTA anticoagulant with K2EDTA to erythrocyte index value. Then on the examination of MCV and MCHC obtained p value <0.05 then there is no significant difference between samples with K3EDTA anticoagulant with K2EDTA to erythrocyte index value.Abstrak: Pemeriksaan darah rutin merupakan pemeriksaan darah yang paling awal atau screening test untuk mengetahui diagnosis suatu kelainan. Darah mudah membeku jika berada diluar tubuh dan bisa dicegah dengan penambahan antikoagulan, salah satunya Ethylene Diamine Tetra Acetate (EDTA). Dewasa ini telah tersedia tabung vakum yang sudah berisi antikoagulan EDTA dalam bentuk  K2EDTA dan  K3EDTA. K3EDTA  biasanya berupa garam yang mempunyai stabilitas yang lebih baik dari garam EDTA yang lain karena menunjukkan pH yang mendekati pH darah yaitu sekitar 6,4. Tujuan dari penelitian ini adalah untuk mengetahui perbedaan hasil indeks eritrosit meliputi MCH, MCV dan MCHC menggunakan antikoagulan K3EDTA dengan K2EDTA. Penelitian ini merupakan penelitian dengan desain cross sectional. Penelitian ini menggunakan sampel darah vena yang dicampur dengan antikoagulan K2EDTA dan darah vena yang dicampur dengan antikoagulan K3EDTA, masing-masing sebanyak 30 sampel. Data dikumpulkan dan dianalisis menggunakan uji beda berpasangan. Berdasarkan analisis data yang telah dilakukan pada pemeriksaan MCH didapatkan nilai p < 0,05 maka ada perbedaan yang signifikan antara sampel dengan antikoagulan K3EDTA dengan K2EDTA terhadap nilai indeks eritrosit. Kemudian pada pemeriksaan MCV dan MCHC didapatkan nilai p < 0,05 maka tidak ada perbedaan yang signifikan antara sampel dengan antikoagulan K3EDTA dengan K2EDTA terhadap nilai indeks eritrosit.


2012 ◽  
Vol 27 (2) ◽  
pp. 264-269 ◽  
Author(s):  
Christian Lorbach ◽  
Ulrich Hirn ◽  
Johannes Kritzinger ◽  
Wolfgang Bauer

Abstract We present a method for 3D measurement of fiber cross sectional morphology from handsheets. An automated procedure is used to acquire 3D datasets of fiber cross sectional images using an automated microtome and light microscopy. The fiber cross section geometry is extracted using digital image analysis. Simple sample preparation and highly automated image acquisition and image analysis are providing an efficient tool to analyze large samples. It is demonstrated that if fibers are tilted towards the image plane the images of fiber cross sections are always larger than the true fiber cross section geometry. In our analysis the tilting angles of the fibers to the image plane are measured. The resulting fiber cross sectional images are distorted to compensate the error due to fiber tilt, restoring the true fiber cross sectional shape. We use an approximated correction, the paper provides error estimates of the approximation. Measurement results for fiber wall thickness, fiber coarseness and fiber collapse are presented for one hardwood and one softwood pulp.


2020 ◽  
Vol 20 (5) ◽  
pp. 748-751
Author(s):  
Seyed Ali Dehghan Manshadi ◽  
Neda Alijani ◽  
Mohammadreza Salehi ◽  
Omid Dadras ◽  
SeyedAhmad SeyedAlinaghi ◽  
...  

Introduction: The aim of this study was to determine the prevalence of exposure to hepatitis A by means of serologic markers in chronic hepatitis B patients, with the secondary aim of finding the best prevention method for hepatitis A infection in susceptible groups of our setting. Methods: During the period between 2016 and 2017, we recruited 403 hepatitis B patients aged more than 14 years and regularly attending the infectious diseases clinic at a referral university hospital, Tehran, Iran. A blood sample was collected from all the patients and tested for hepatitis A IgG. The data was analyzed by SPSS v.19. Results: Although none of the patients had previously received hepatitis A vaccine, the results for serologic level of hepatitis A IgG, demonstrated positive results in 379 (94%) cases. The mean age of patients with negative and positive IgG was 29.17 and 42.46 years, respectively; the difference was statistically significant (P≤0.001). The majority of seronegative patients were young adults aged < 25 years and 25 to 35 years (P <0.001). Conclusion: Seroprevalence of hepatitis A in chronic HBV patients in Iran is high. As HBV infected patients younger than 35 years could be seronagative for HAV infection, evaluation of these patients for HAV infection and vaccination of seronegative patients would be a reasonable approach.


Author(s):  
I Ketut Widana

The working practice of the engineering students is part of the learning process that is irreducible and indispensable. The composition of  lecturing between theoretical and practical one is 40% to 60%. With this condition, the students spend more time at the laboratory. Generally, the students perform in the laboratory work by standing position. The design of research is observational cross-sectional. The method applied is observation, interview and measuring. The subjects of research are practicing students amounting to 21 students. Referring to the analysis of statistical test or Wilcoxon signed ranks test, the difference of effect of work position is significant, namely p < 0.05 towards musculoskeletal disorders (MSDs) before and after working. The quantity of the average complaint after working is score 44.62 ± 9.47. The result of Wilcoxon signed rank test shows that there is significant different effects of standing work position, namely p < 0.05 towards fatigue generally before and after working. The degree of the working pulse is on the average of 110.78  ± 17.80 bpm (beats per minutes) which can be categorized into the medium workload. Using paired t-test, the result is p < 0.05.


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