scholarly journals KARAKTERISTIK MEKANIS DAN PERILAKU LENTUR BALOK KAYU LAMINASI MEKANIK

2016 ◽  
Vol 3 (1) ◽  
Author(s):  
Ratna Prasetyowati Putri ◽  
Fengky Satria Yoresta

Penggunaan paku atau baut maupun kombinasinya dengan perekat sebagai penghubungantar lamina pada balok kayu laminasi akan mempengaruhi karakteristik mekanis danperilaku keruntuhan balok tersebut. Penelitian ini bertujuan menentukan karakteristikmekanis dan menganalisa perilaku lentur balok kayu laminasi mekanik. Tiga tipe baloklaminasi digunakan dalam penelitian ini, ditambah balok glulam sebagai kontrol. Balok tipe 1menggunakan baut/paku di sepanjang bentang sebagai penghubung antar lamina. Balok tipe 2hanya menggunakan paku/baut pada sepertiga bentang di kedua ujung balok, sedangkan padasepertiga bentang lainnya menggunakan perekat. Paku atau baut pada balok tipe 3ditempatkan pada sepertiga bentang di tengah balok dan sisanya menggunakan perekat.Pengujian lentur dilakukan dengan metode one point centre loading dengan jarak antartumpuan 90cm. Hasil penelitian menyimpulkan balok tipe 3 memiliki nilai ModulusElastisitas (MOE) tertinggi dibandingkan balok tipe 1 dan tipe 2. MOE balok laminasitertinggi terdapat pada balok laminasi-paku diameter 0.3 cm tipe 3 (52162.95 kg/cm2)sedangkan terendah pada balok laminasi-paku diameter 0.3 cm tipe 1 (11077.41 kg/cm2).Modulus of Rupture (MOR) tertinggi terdapat pada balok laminasi-paku diameter 0.3 tipe 3(368.16 kg/cm2) dan terendah pada balok laminasi-baut diameter 0.5 cm tipe 3 (207.36kg/cm2). Balok kontrol memiliki nilai MOE dan MOR tertinggi dibandingkan semua baloklaminasi mekanik. Posisi penempatan baut, paku, dan perekat pada balok laminasi hanyaberpengaruh terhadap nilai MOE. Semua kerusakan yang ditemukan pada balok laminasimekanik adalah berupa kerusakan lentur dan geser antar lamina The use of nails or bolts or its combination with adhesive as connector between lamina on laminated wood beams will affect the mechanical characteristics and collapse behavior of the beam. This study aims to determine the mechanical characteristics and analyze the flexural behavior of mechanical-laminated wood beams. Three types of the mechanical-laminated beams used in this study beside glulam beams as control. The type 1 using bolts/nails along the span as a connector between laminas. Beam type 2 only using nails/bolts on the one-third span at both ends of the beam, while adhesive on the other space of span. Nails or bolts on beam type 3 is placed on the one-third span at the middle of the beam, and the other space using adhesive. Bending test was conducted by using one-point centre loading method with 90 cm of span. The study concluded that beam type 3 has the highest value of Modulus of Elasticity (MOE) compared to beam type 1 and type 2. The highest MOE for laminated beams is found on nail-laminated beam with diameter of 0.3 cm type 3 (52162.95 kg/cm2) while the lowest one is on nail-laminated beam with diameter of 0.3 cm type 1 (11077.41 kg/cm2). The highest Modulus of Rupture (MOR) is found on nail-laminated beam with diameter of 0.3 cm type 3 (368.16 kg/cm2), and the lowest one is on bolt-laminated beam with diameter of 0.5 cm type 3 (207.36 kg/cm2). The control beam has the highest value of MOE and MOR compared to all mechanical-laminated wood beams. Position of bolts, nails, and adhesive on the laminated beams is only affects to MOE. All damage found on the mechanical-laminated beams is in form of flexural collapse and shear failure among laminas.

1928 ◽  
Vol 28 (3) ◽  
pp. 250-266 ◽  
Author(s):  
William Gunn ◽  
Fred Griffith

1. The bacteriological examination of the throat or nose in 100 cases of scarlet fever on admission to hospital showed the following incidence of the different serological types of streptococci. Of 91 cases yielding positive results on the first examination, haemolytic streptococci of Type 1 were found in 8, Type 2 in 14, Type 3 in 26 and Type 4 in 12; the remaining 31 fell into the heterogeneous group. In the 9 patients who gave a negative swab on admission a later test showed Type 1 in 2 cases, Type 2 in 4 cases, Type 3 in 1 case and heterogeneous strains in 2 cases.2. The heterogeneous group comprised individualistic strains, none of which occurred with sufficient frequency to form a fifth type.3. In 50 out of the 100 cases examined at weekly intervals the type of streptococcus remained the same throughout the attack.4. In 50 cases there was a change of type during the course of the disease; a second type appeared in 38, a third in 10 and a fourth in 2.5. The change of type was considered to be a reinfection since it appeared most often in the youngest children and after the 3rd week of treatment; the source of reinfection was traced in two instances.6. In 3 patients, in whom the Dick reaction remained positive, the appearance of the new type coincided with a second attack of clinical scarlatina.7. Of the 50 patients in whom no change of type was demonstrated 20 still carried the haemolytic streptococci on discharge after periods in hospital ranging from 4 to 8 weeks.8. Of the total 100 cases there were on discharge 49 throat carriers of haemolytic streptococci and 6 nose carriers. None of the 55, so far as was ascertained, gave rise to “return cases” of scarlet fever.9. There was evidence of correlation between serological type of streptococcus on the one hand and severity of scarlatinal attack and occurrence of complications on the other. The importance of this in hospital practice is emphasised.10. The Dick test and Schultz-Charlton reaction were carried out on all cases in the series; the results indicated that the four serological types have different immunological values.11. The evidence in favour of qualitative as opposed to quantitative differences in toxin production by the different types is discussed.


2020 ◽  
Vol 8 (3) ◽  
pp. 080-090
Author(s):  
FJ Pérez Lara ◽  
R Zubizarreta Jimenez ◽  
JM Hernández González ◽  
T Prieto-Puga ◽  
F Moya Donoso

Introduction: In medicine, sutures have been used for thousands of years to close wounds. However, despite the great advances that have been made in technology, little progress has taken place in suturing techniques and most surgeons continue to use the same two classical techniques (continuous suture or interrupted suture). This paper proposes a suturing technique (“double diabolo”) in which a pattern of eight 45-degree angles is formed, in the view that this achieves a notable reduction in the tension exerted (30% at each angle), thereby increasing the overall strength of the suture. Material and Method: In this study, we compare the physical tensions exerted on the suture thread and its entry/exit points, on the one hand by the two techniques most often used – interrupted suture (Type 1) and continuous suture (Type 2) – and on the other, by the proposed “double-diabolo” suture (Type 3). Results: The Type 3 suturing method produced the lowest levels of tension on the thread, almost 65% less than those of Type 1 and 50% less than those of Type 2. The tension on the wound was also considerably lower, with reductions of 33% and 50% in comparison with Types 1 and 2, respectively. Conclusions: The results obtained in this study corroborate our hypothesis that the proposed double-diameter suture method exerts less tension on the thread and on the entry/exit points than conventional techniques. Theoretically it would be recommended for cases in which the suture must withstand significant tension as laparotomy closure


Author(s):  
A.M. Satarkulova

The assessment and dynamic control over students’ status is a very important task. It allows timely detection of prenosological status prior to pathology and health maintenance in students. The objective of the paper is to assess the adaptive abilities of the body, to analyze changes in heart rate variability indicators in students with various types of autonomic regulation, to identify prenosological status and precursory pathological symptoms. Materials and Methods. The study enrolled 302 students from India, aged 21.54±1.43. Programming complex «Psychophysiologist» was used to register the main HRV parameters within 5 minutes. Health status was evaluated according to the index of functional changes and the scale of functional states. Results. N.I. Shlyk (2009) distinguished two groups of students with different types of autonomic regulation: type 1 (53 %) with moderate and type 2 (5 %) with marked characteristics of central regulation profile, type 3 (35 %) with moderate and type 4 (7 %) with marked characteristics of autonomous regulation profile. Main parameters of HRV and adaptation potential were defined for each student.All the parameters characterized functional and health status. Conclusions. It was shown that 82 % of trial subjects (type 1), 53 % (type 2), 94 % (type 3) and 95 % (type 4) demonstrated satisfactory adaptation and their physiological processes were at an optimal level. 18 % of students (type 1) demonstrated reduced adaptive abilities of the body. Moreover, they were under moderate stress. 47 % of subjects (type 2) were also under a significant stress, which was proven by excessively high SI, low SDNN and TP, and an increased index of functional changes. 5 % of students (type 4) revealed dysfunctional characteristics in the heart rhythm, peculiar to pathology. Keywords: foreign students, heart rate variability, types of autonomic regulation, adaptation potential, functional status. Оценка состояния студентов и динамический контроль за ним является важной задачей, поскольку позволяет своевременно выявлять у студентов донозологические состояния, предшествующие патологии, и способствовать сохранению здоровья. Цель. Оценка адаптивных возможностей организма, анализ изменений показателей вариабельности сердечного ритма у студентов с различными типами вегетативной регуляции, выявление донозологических состояний и ранних признаков патологии. Материалы и методы. В исследовании участвовало 302 студента в возрасте 21,54+1,43 года из Индии. Регистрировались основные параметры ВСР в течение 5 мин с использованием программно-аппаратного комплекса «Психофизиолог». Состояние и уровень здоровья оценивались по индексу функциональных изменений и шкале функциональных состояний. Результаты. По способу, предложенному Н.И. Шлык, выделены группы студентов с различными типами вегетативной регуляции: I (53 %) и II типы (5 %) – с умеренным и выраженным преобладанием центрального контура регуляции соответственно, III (35 %) и IV типы (7 %) – с умеренным и выраженным преобладанием автономного контура регуляции соответственно. У каждого из студентов определены основные параметры ВСР и адаптационного потенциала, характеризующие функциональное состояние и уровень здоровья. Выводы. Показано, что для 82 % обследуемых с I типом, 53 % со II типом, 94 % c III типом и 95 % с IV типом регуляции характерно состояние удовлетворительной адаптации, физиологические процессы сохраняются на оптимальном уровне. В группе студентов I типа у 18 % студентов адаптивные возможности организма снижены, выявлено состояние умеренного напряжения. У 47 % обследуемых II типа также зафиксировано состояние резко выраженного напряжения, индикатором которого является чрезмерно высокое значение SI, низкие величины SDNN и ТP, повышенное значение индекса функциональных изменений. В группе студентов с IV типом у 5 % учащихсяв регуляции ритма сердца выявлены дисфункциональные признаки, характерные для патологии. Ключевые слова: иностранные студенты, вариабельность сердечного ритма, типы вегетативной регуляции, адаптационный потенциал, функциональное состояние.


1954 ◽  
Vol 32 (1) ◽  
pp. 119-125
Author(s):  
W. Wood ◽  
Eina M. Clark ◽  
F. T. Shimada ◽  
A. J. Rhodes

Studies on the basic immunology of poliomyelitis in Canadian Eskimos have been continued. Some 87 sera collected from Eskimos at Pangnirtung, Baffin Island, have been examined for the presence of Type 1 and Type 3 poliomyelitis antibody by quantitative tests in tissue cultures. The same sera were previously examined for Type 2 antibody by quantitative tests in mice. The results of the three determinations are now presented together for comparison. These sera came from Eskimos aged 2 to 72 years of age. None of the Eskimos showed any evidence of paralysis. Examination of the medical records did not suggest that any paralytic disease had been present in this part of Baffin Island. Very few of the sera showed the presence of poliomyelitis antibody; thus, Type 1 antibody was demonstrated in the sera of 8%, Type 2 antibody in the sera of 9%, and Type 3 antibody in the sera of 14%. No significant number of Eskimos below the age of 45 years had acquired poliomyelitis antibody. The antibody titers mostly ranged between 10−1.0 and 10−2.0, and were significantly lower than the titers customarily found in recently paralyzed cases. These findings suggest that poliomyelitis infection occurred in Pangnirtung Eskimos many years before the date on which the samples were taken (1951). These results point to the worldwide prevalence of the three types of poliomyelitis virus.


2021 ◽  
Vol 47 (02) ◽  
pp. 192-200
Author(s):  
James S. O'Donnell

AbstractThe biological mechanisms involved in the pathogenesis of type 2 and type 3 von Willebrand disease (VWD) have been studied extensively. In contrast, although accounting for the majority of VWD cases, the pathobiology underlying partial quantitative VWD has remained somewhat elusive. However, important insights have been attained following several recent cohort studies that have investigated mechanisms in patients with type 1 VWD and low von Willebrand factor (VWF), respectively. These studies have demonstrated that reduced plasma VWF levels may result from either (1) decreased VWF biosynthesis and/or secretion in endothelial cells and (2) pathological increased VWF clearance. In addition, it has become clear that some patients with only mild to moderate reductions in plasma VWF levels in the 30 to 50 IU/dL range may have significant bleeding phenotypes. Importantly in these low VWF patients, bleeding risk fails to correlate with plasma VWF levels and inheritance is typically independent of the VWF gene. Although plasma VWF levels may increase to > 50 IU/dL with progressive aging or pregnancy in these subjects, emerging data suggest that this apparent normalization in VWF levels does not necessarily equate to a complete correction in bleeding phenotype in patients with partial quantitative VWD. In this review, these recent advances in our understanding of quantitative VWD pathogenesis are discussed. Furthermore, the translational implications of these emerging findings are considered, particularly with respect to designing personalized treatment plans for VWD patients undergoing elective procedures.


2021 ◽  
Author(s):  
Hui Xu ◽  
Lei Chen ◽  
Wansuo Duan

AbstractThe optimally growing initial errors (OGEs) of El Niño events are found in the Community Earth System Model (CESM) by the conditional nonlinear optimal perturbation (CNOP) method. Based on the characteristics of low-dimensional attractors for ENSO (El Niño Southern Oscillation) systems, we apply singular vector decomposition (SVD) to reduce the dimensions of optimization problems and calculate the CNOP in a truncated phase space by the differential evolution (DE) algorithm. In the CESM, we obtain three types of OGEs of El Niño events with different intensities and diversities and call them type-1, type-2 and type-3 initial errors. Among them, the type-1 initial error is characterized by negative SSTA errors in the equatorial Pacific accompanied by a negative west–east slope of subsurface temperature from the subsurface to the surface in the equatorial central-eastern Pacific. The type-2 initial error is similar to the type-1 initial error but with the opposite sign. The type-3 initial error behaves as a basin-wide dipolar pattern of tropical sea temperature errors from the sea surface to the subsurface, with positive errors in the upper layers of the equatorial eastern Pacific and negative errors in the lower layers of the equatorial western Pacific. For the type-1 (type-2) initial error, the negative (positive) temperature errors in the eastern equatorial Pacific develop locally into a mature La Niña (El Niño)-like mode. For the type-3 initial error, the negative errors in the lower layers of the western equatorial Pacific propagate eastward with Kelvin waves and are intensified in the eastern equatorial Pacific. Although the type-1 and type-3 initial errors have different spatial patterns and dynamic growing mechanisms, both cause El Niño events to be underpredicted as neutral states or La Niña events. However, the type-2 initial error makes a moderate El Niño event to be predicted as an extremely strong event.


Author(s):  
Mi Hyeon Seong ◽  
Eunyoung Shin ◽  
Sohyune Sok

The purpose of this study is to identify the types of perception of successful aging in middle-aged men and to analyze and describe the characteristics of each type of successful aging perception of middle-aged men in South Korea. This study uses an exploratory study design, applying the Q methodology, which is a subjective research method. The participants were 25 middle-aged men (40 to 60 years old) living in C, Y, and B cities, which were P-samples that were judged to best reveal the successful aging of middle-aged men. In this study, principal component analysis of the PQ method program was used. The five perception types of successful aging among middle-aged men are Type 1 for the “leisure type”, Type 2 for the “mature type”, Type 3 for the “health-oriented type”, Type 4 for the “patriarchal type”, and Type 5 for the “family-centered type”. The mature type had the highest variance among the five types, and the leisure type was the type that showed the second-highest variance. In nursing practice, nurses need to pay attention to the successful aging perceptions of middle-aged Korean men for their successful aging in the future.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2645
Author(s):  
Omer Cohen ◽  
Dieter D. Bosshardt ◽  
Evegeny Weinberg ◽  
Gil Slutzkey ◽  
Ofer Moses

Stress concentrated at an implant’s neck may affect bone-to-implant contact (BIC). The objective of this study was to evaluate four different implant neck designs using two different drilling protocols on the BIC. Methods: Ninety-six implants were inserted in 12 minipigs calvarium. Implants neck designs evaluated were: type 1–6 coronal flutes (CFs), 8 shallow microthreads (SMs); type 2–6 CFs,4 deep microthreads (DMs); type 3–4 DMs; type 4–2 CFs, 8 SMs. Two groups of forty-eight implants were inserted with a final drill diameter of 2.8 mm (DP1) or 3.2 mm (DP2). Animals were sacrificed after 1 and 3 months, total-BIC (t-BIC) and coronal-BIC (c-BIC) were evaluated by nondecalcified histomorphometry analysis. Results: At 1 month, t-BIC ranged from 85–91% without significant differences between implant types or drilling protocol. Flutes on the coronal aspect impaired the BIC at 3 m. c-BIC of implant types with 6 CFs was similar and significantly lower than that of implant types 3 and 4. c-BIC of implant type 4 with SMs was highest of all implant types after both healing periods. Conclusions: BIC was not affected by the drilling protocol. CFs significantly impaired the -BIC. Multiple SMs were associated with greater c-BIC.


2021 ◽  
Vol 19 (1) ◽  
pp. 614-634
Author(s):  
Ayodele T. Odularu ◽  
Peter A. Ajibade

Abstract The aim of this review study was to assess the past significant events on diabetes mellitus, transformations that took place over the years in the medical records of treatment, countries involved, and the researchers who brought about the revolutions. This study used the content analysis to report the existence of diabetes mellitus and the treatments provided by researchers to control it. The focus was mainly on three main types of diabetes (type 1, type 2, and type 3 diabetes). Ethical consideration has also helped to boost diabetic studies globally. The research has a history path from pharmaceuticals of organic-based drugs to metal-based drugs with their nanoparticles in addition to the impacts of nanomedicine, biosensors, and telemedicine. Ongoing and future studies in alternative medicine such as vanadium nanoparticles (metal nanoparticles) are promising.


2016 ◽  
Vol 849 ◽  
pp. 513-519
Author(s):  
Qing Quan Zhang ◽  
Ming Yang Li ◽  
Ran Wei ◽  
Hui Yun Wu ◽  
Zhen Rui Li

Ni-Cr-Co type Nickel-based super alloy Inconel 740H was studied. The effect of Nb, Al and Ti on the equilibrium of this alloy was analyzed by JMatPro software. The amount of Ti and Nb should be controlled by 1.50wt.%, and meanwhile, Al should be 1.0-2.0wt.%. If Mo and W were added the amount of Mo should be in the range of 1.0-2.0wt. %, and W should be about 1.0wt.%. Based on these results, three types of new alloys were designed, which contain Ni-Cr-Co-Mo type (1#), Ni-Cr-Co-W type (2#) and Ni-Cr-Co-Mo-W type (3#). Compared with the Ni-Cr-Co type Inconel 740H alloy, the room temperature strength, high temperature strength and high temperature durable performance of the three new alloys improved, which can provide the evidence and reference to optimize the chemical composition of Inconel 740H alloy, i.e., adding 1.50wt.% Mo and 1.0wt.% W individually or together.


Sign in / Sign up

Export Citation Format

Share Document