Utjecaj legirajućih elemenata u aluminiju na usitnjavanje zrna s AlTi5B1

This work deals with the influence of alloying elements in aluminium on the grain refinement with various additions of AlTi5B1. Grain-refinement tests were made at a cooling rate of 15 °C/s. The results revealed that in both aluminium and an Al-Fe alloy the grain size decreases with increasing additions of the AlTi5B1 grain refiner. We found that for the same boron content the grain size was smaller in the case of the Al-Fe alloy. The difference in the grain sizes for the same content of boron was approximately 15 μm; this is considerably smaller than the difference between the grain sizes in samples with the same difference of growth-restricting factor made at slower cooling rates.Članak se bavi utjecajem legirajućih elemenata u aluminiju na usitnjavanje zrna s različitih dodatcima AlTi5B1. Ispitivanje usitnjavanja zrna je provedeno pri brzini hlađenja od 15 °C/s. Rezultati su otkrili da i u aluminiju i u Al-Fe leguri veličina zrna pada s povećanjem dodatka AlTi5B1 cjepiva. Utvrdili smo da je za isti dodatak bora veličina zrna manja u Al-Fe leguri. Razlika u veličini zrna za isti dodatak bora je bila približno 15 μm; što je značajno manje od razlike u veličini zrna u uzorcima s istom razlikom faktora ograničavanja rasta, pri manjim brzinama hlađenja

Utjecaj legirajućih elemenata u aluminiju na usitnjavanje zrna s AlTi5B1

This work deals with the influence of alloying elements in aluminium on the grain refinement with various additions of AlTi5B1. Grain-refinement tests were made at a cooling rate of 15 °C/s. The results revealed that in both aluminium and an Al-Fe alloy the grain size decreases with increasing additions of the AlTi5B1 grain refiner. We found that for the same boron content the grain size was smaller in the case of the Al-Fe alloy. The difference in the grain sizes for the same content of boron was approximately 15 μm; this is considerably smaller than the difference between the grain sizes in samples with the same difference of growth-restricting factor made at slower cooling rates.Članak se bavi utjecajem legirajućih elemenata u aluminiju na usitnjavanje zrna s različitih dodatcima AlTi5B1. Ispitivanje usitnjavanja zrna je provedeno pri brzini hlađenja od 15 °C/s. Rezultati su otkrili da i u aluminiju i u Al-Fe leguri veličina zrna pada s povećanjem dodatka AlTi5B1 cjepiva. Utvrdili smo da je za isti dodatak bora veličina zrna manja u Al-Fe leguri. Razlika u veličini zrna za isti dodatak bora je bila približno 15 μm; što je značajno manje od razlike u veličini zrna u uzorcima s istom razlikom faktora ograničavanja rasta, pri manjim brzinama hlađenja

Pretapanje aluminiuma sa dodatkom inokulanta AlTi5B1 i AlTi3C0,15

It was found that concentration of boron in aluminium with the addition of AlTi5B1 grain refiner is decreasing during remelting as a consequence of TiB2 particles settling down due to gravity. TiB2 particles remained in aluminium after four remelts shows lower effect of grain refinement compared to non-remelted samples with the same TiB2 content. It was also found that TiC particles are still present in aluminium with the addition of AlTi3C0,15 grain refiner after four remelts and they probably participate in nucleation of α-Al grains.Istraživanjem je utvrđeno da se s pretapanjem aluminiuma, kod dodavanja modifikatora AlTi5B1, koncentracija bora u leguri smanjuje, što je posljedica gravitacijske segregacije TiB2. Kod istog sadržaja čestica TiB2 u leguri, ima taj inokulant poslije četiri pretapanja, manji efekt na smanjenje velikosti kristalnih zrna, kao u primarno taljeni leguri. Isto tako je bilo ustanovljeno, da su u aluminiumu sa dodatkom AlTi3C0,15, i poslije četiri pretapanja još prisutne čestice TiC, koje vjerojatno sudjeluju u procesu nukleacije zrna α -Al

Ventilatory capacity in stone saw-mill workers

Ispitali smo da li brački vapnenac, koji sadrži neznatnu količinu silicija, utječe na poremetnju ventilacijskih funkcija muškaraca zaposlenih u pilani kamena. Ispitane su ventilacijske funkcije: VK, FEV1, FEV 1% VK, MEF25, MEF50, i MEF75, a uzorak ispitanika analiziran je s obzirom na nepušače i pušače. Analiza varijance utvrdila je homogenu raspodjelu parametra VK, dok su ostale bile heterogeno distribuirane. To se može objasniti navikom pušenja kao ponderalnim faktorom, a ne ekspozicijom prašini vapnenca. Pretpostavlja se da proces obrade bračkog vapnenca u pilani kamena ne uzrokuje poremećaj ventilacijskih funkcija.The study aims at assessing whether occupational exposure to Brae limestone, which contains a minute amount of silica, induces disorders of ventilatory capacity. It included 71 male workers employed in a stone saw-mill and 134 controls. The ventilatory functions VC, FEV1, FEY 1% VC, MEF25, MEF50 i MEF75 were examined, and the values analysed in respect to smoking habit. Variance analysis established a homogenous distribution of VC parameters, while others were heterogeneously distributed. This can be explained by smoking habit as assessable factor, and not by exposure to limestone dust. It is assumed that the production of Brae limestone in the stone saw-mill does not cause disorders in ventilatory function

Comparative Analysis of Qualitative Dermatoglyphic Traits of Albanian and Turkish Populations Living in the Area of Dukagjin Valley in Kosovo

Dermatoglyphic prints were collected from 800 inhabitants of Dukagjin valley in Kosovo. The sample consisted of two ethnically different sub-populations who refer themselves as Albanians (N=400) and Turks (N=400). Qualitative analysis of prints concerned the frequency of the patterns on fingers (arch, ulnar and radial loop, whorl, accidental whorl) and on palms (Thenar and I, II, III, and IV interdigital area and the hypothenar, main line index, and the axial »t« triradius position). As was expected due to previous study of quantitative dermatoglyphic traits, in the same population the Albanians and Turks showed to be significantly different in most explored qualitative dermatoglyphic variables. Found differences indicated that the reproductive isolation between the Albanian and Turkish population in Kosovo is substantial, despite the fact that those two ethnic sub-populations live in the close vicinity through several centuries

A Large Cross-Sectional Study of Health Attitudes, Knowledge, Behaviour and Risks in the Post-War Croatian Population (The First Croatian Health Project*)

As the liberation of occupied Croatian territories ended the war in the country in 1995, the Ministry of Health and Croatian Health Insurance Institute have agreed to create the new framework for developing a long-term strategy of public health planning, prevention and intervention. They provided financial resources to develop the First Cro-atian Health Project, the rest of the support coming from the World Bank loan and the National Institute of Public Health. A large cross-sectional study was designed aiming to assess health attitudes, knowledge, behaviour and risks in the post-war Croatian population. The large field study was carried out by the Institute for Anthropological Research with technical support from the National Institute of Public Health. The field study was completed between 1995–1997. It included about 10,000 adult volunteers from all 21 Croatian counties. The geographic distribution of the sample covered both coastal and continental areas of Croatia and included rural and urban environments. The specific measurements included antropometry (body mass index and blood pressure). From each examinee a blood sample was collected from which the levels of total plasma cholesterol (TC), triglycerides (TG), HDL-cholesterol (High Density Lipoprotein), LDL-cholesterol (Low Density Lipoprotein), lipoprotein Lp(a), and haemostatic risk factor fibrinogen (F) were determined. The detailed data were collected on the general knowledge and attitudes on health issues, followed by specific investigation of smoking history, alcohol consumption, nutrition habits, physical activity, family history of chronic non-communicable diseases and occupational exposures. From the initial database a targeted sample of 5,840 persons of both sexes, aged 18–65, was created corresponding by age, sex and geographic distribution to the general Croatian population. This paper summarises and discusses the main findings of the project within this representative sample of Croatian population

Testing Mode-Coupling Theory for a Supercooled Binary Lennard-Jones Mixture II: Intermediate Scattering Function and Dynamic Susceptibility

We have performed a molecular dynamics computer simulation of a supercooled binary Lennard-Jones system in order to compare the dynamical behavior of this system with the predictions of the idealized version of mode-coupling theory (MCT). By scaling the time $t$ by the temperature dependent $\alpha$-relaxation time $\tau(T)$, we find that in the $\alpha$-relaxation regime $F(q,t)$ and $F_s(q,t)$, the coherent and incoherent intermediate scattering functions, for different temperatures each follows a $q$-dependent master curve as a function of scaled time. We show that during the early part of the $\alpha$-relaxation, which is equivalent to the late part of the $\beta$-relaxation, these master curves are well approximated by the master curve predicted by MCT for the $\beta$-relaxation. This part is also fitted well by a power-law, the so-called von Schweidler law. We show that the effective exponent $b'$ of this power-law depends on the wave vector $q$ if $q$ is varied over a large range. The early part of the $\beta$-relaxation regime does not show the critical decay predicted by MCT. The $q$-dependence of the nonergodicity parameter for $F_{s}(q,t)$ and $F(q,t)$ are in qualitative agreement with MCT. On the time scale of the late $\alpha$-relaxation the correlation functions show a Kohlrausch-Williams-Watt behavior (KWW). The KWW exponent $\beta$ is significantly different from the effective von Schweidler exponent $b'$. At low temperatures the $\alpha$-relaxation time $\tau(T)$ shows a power-law behavior with a critical temperature that is the same as the one found previously for the diffusion constant [Phys. Rev. Lett. {\bf 73}, 1376 (1994)]. The critical exponent of this power-law and the von Schweidler exponent $b'$ fulfill the connection proposed by MCT between these two quantities. We also show that theComment: 28 Pages of REVTEX, Figures available from W. Ko

Inbreeding and Learning Disability in Croatian Island Isolates

The aim of this study was to investigate the prevalence of learning disability (LD) in isolate populations with different inbreeding coefficients (F). Prevalence of LD and F were determined in 10 villages from five Croatian islands: Bra~, Hvar, Kor~ula, Lastovo and Susak. For the purpose of this study, LD was defined as the inability to attend the public school system. As the elementary schools (grade 1–8) in the place of the study are both public and compulsory, the assessment of child\u27s inability to attend the school is performed at the age of six. This is required by all children in the country based on standard set of tests of cognitive performance defined by the Ministry of Education and Culture of the Republic of Croatia. The average inbreeding coefficients in each village population (F) were estimated in a random sample of 20–30% adults in each of the 10 villages based on 4 ancestral generations and using Wright\u27s path method. Prevalence of LD ranged from 0.43% to 2.47%, and the inbreeding coefficients ranged from 0.8% to 4.9%. The Pearson\u27s correlation coefficient between F and LD prevalence was 0.80 (p<0.01). Although the relative risk per 5% inbreeding appeared very high (about 10), the absolute risk only increased from 0.18% to 1.77%. The genetic effect of inbreeding (GEI) was approximately 0.69% and the population-attributable fraction 76.6%. A review of the literature and the results of this study lead to a conclusion that a very large number of predominantly recessive genetic factors might mediate the genetic susceptibility to various forms of LD in these populations

Comparative Analysis of Qualitative Dermatoglyphic Traits of Albanian and Turkish Populations Living in the Area of Dukagjin Valley in Kosovo

Dermatoglyphic prints were collected from 800 inhabitants of Dukagjin valley in Kosovo. The sample consisted of two ethnically different sub-populations who refer themselves as Albanians (N=400) and Turks (N=400). Qualitative analysis of prints concerned the frequency of the patterns on fingers (arch, ulnar and radial loop, whorl, accidental whorl) and on palms (Thenar and I, II, III, and IV interdigital area and the hypothenar, main line index, and the axial »t« triradius position). As was expected due to previous study of quantitative dermatoglyphic traits, in the same population the Albanians and Turks showed to be significantly different in most explored qualitative dermatoglyphic variables. Found differences indicated that the reproductive isolation between the Albanian and Turkish population in Kosovo is substantial, despite the fact that those two ethnic sub-populations live in the close vicinity through several centuries