The Influence of Laser Surface Hardening on Dry Sliding Wear Behaviour of Steel Ck45

This paper describes the effect of laser surface treatment on wearesistance of steel Ck45 .A Pulse Nd:YAG laser with wave length 1064 nm and pulse duration 100 ns was used by applying one pulse ,two pulses with different laser energies (500, 750, 1000 mJ). Pin-on-disc technique was done to define wear rate with different forces (5, 10, 15, 20, 25 N) and different sliding speeds (1.319 ,2.199, 3.078, 3.958 m/s) for constant time (20 min) and constant rotating disc 720 r.p.m with 45HRC .Also defined microhardness which decreases far from the hardened surface , depth of hardening was evaluated through optical microscopy . The results of this work demonstrated that improvement in wear resistance for 1000 mJ laser energy more than the other energies for one pulse and two pulses ,while wear resistance for two pulses more than one pulse for all the energies . X-ray analysis results show that precipitation of another carbides like iron carbides ,chromium carbides ,manganese carbides after the treatment by laser

Puurakenteinen kerrostalo Vihiluotoon

Tiivistelmä. Kandidaatintyöni on asuntosuunnittelun kurssilla suunniteltu puukerrostalo Vihiluotoon

”Tää (työyhteisö) on ainut, joka pitää meijjät tässä, että me jaksetaan tätä tässä arvokkaassa, mutta todella todella uuvuttavassa ja voimia vievässä (työssä)”:opettajien ja rehtorien kertomuksia työyhteisön toimivuudesta ja sen rakentumisesta

Tiivistelmä. Pro gradu -tutkielmassamme tutkimme koulujen työyhteisön toimivuuden rakentumista opettajien ja rehtorien näkökulmasta. Tutkimuksemme taustalla on ajatus koulun työyhteisöstä osana laajempaa yhteisöä, koulua, johon työyhteisö kokonaisvaltaisesti vaikuttaa.  Tämän myötä koulussa työyhteisön toiminta vaikuttaa myös oppilaiden toimintaan ja hyvinvointiin. Muuttuvassa ja haastavassa työympäristössä työyhteisö voi olla myös opettajan työhyvinvoinnin kannattaja. Teoriaosuudessa tarkastelemme tärkeitä työyhteisön toimivuutta taustoittavia elementtejä ja esimerkkejä työyhteisön toimivuuden rakentumisesta. Aikaisemmat työyhteisön toimivuutta koskevat tutkimukset ovat toteutettu muilla kuin opetusaloilla, joten koulun työyhteisön toimivuuden rakentumisesta löytyy niukasti tietoa.  Menetelmänä käytämme narratiivista tutkimusmenetelmää. Aineistonamme on kahden koulun työyhteisöjen haastattelut ja olemme analysoineet aineiston hyödyntämällä laadullista sisällönanalyysia sekä narratiivista analyysia.  Haluamme narratiivisen tutkimuksen periaatteiden mukaisesti tuoda työyhteisön yhteinen ääni esille. Tutkimuksemme tuloksissa korostuivat kahden eri koulun työyhteisöjen toiminnan rakentuminen. Koulujen työyhteisöjen luonteen perusteella nimesimme työyhteisöt Inhimilliseksi työyhteisöksi ja Kehittäjätyöyhteisöksi.  Inhimillisen  työyhteisön toimivuus on rakentunut vuorovaikutuksesta, kollegiaalisuudesta ja yhteistyöstä.  Inhimillisyys näkyy tavassa kohdata työyhteisön ihmiset.  Kehittäjätyöyhteisön toimivuuden rakentuminen on  vielä  kesken suuren työntekijävaihtuvuuden vuoksi.  Vaihtuvuus on arvokas tulos itsessään, sillä se kertoo oman näkökulmansa toimivuudesta. Vahvuuksia tämän yhteisön toimivuuden rakentumisessa ovat avoin vuorovaikutus sekä kehittämisinto.Narratives by teachers and principals about work community functionality and it’s construction. Abstract. In our Master’s Thesis we explore how a well-functioning work community is constructed from the point of view of teachers and principals. Our research is based on the idea that the school’s work community has a pervasive effect on the school itself. Thus, the functioning of the work community also affects the functioning and well-being of students. In a changing and challenging work environment the work community can also support teachers’ well-being. In the Theory section we examine elements that lay the groundwork for a well-functioning work community and examples of how it is constructed. Previous studies have been conducted outside the field of education so there is scant information on work communities in schools. We use the narrative research approach and our material consists of interviews in two schools’ work communities. We have utilized qualitative content analysis as well as narrative analysis. In keeping with the principles of narrative research, we wish to bring out the common voice of the work community. Our results highlighted the differences between how the functioning of the two communities was constructed. Based on the character of the communities we named them the Humane Community and the Developer Community. The functioning of the Humane Community is constructed by interaction, collegiality and cooperation. The humaneness can be seen in the way people are treated when encountered. The Developer Community is still in the middle of constructing its functioning due to high turnover. The turnover rate itself is a valuable result, since it reveals something about the functioning of the community. This community’s strengths are open interaction and eagerness towards development

Effect of Laser Surface Treatment on the Properties of Composite Material Produced by Powder Technology

In this investigation we obtained composite material by the powder technology process of metallic matrix which posses particle size ( 20µm ) with changing the percentage of additive ceramic material which posses particle size ( 53 µm) which is widely used in aerospace vehicle ,medical and engineering applications. Macro hardness and physical properties (density ,porosity), also microstructure which were produced from laser surface treatment of the composite material were done into two stages: 1- To study the first stage: study the effect of the changing in the percentage of the additive ceramic material SiC (%5 ,%10 ,%15 ,%20 ) on hardness and physical properties of composite material before and after sintering of the specimens. 2-The second stage :The study the effect of laser surface treatment on hardness and physical properties with different percentages.Pluse Nd:YAG laser was used with frequency ( 3Hz ),wave length (1064nm), laser energy ( 1J ) and pluse width (100 nm) and study the effect of one pluse and two pluses on hardness after sintering of the specimens. The results which were obtained experimentally reveals the impovment in the structure and hardness and also the physical properties (density ,porosity) for the specimens treated by laser with two pluses and additive percentage (%20 )

Epidemiology of herpes simplex virus type 2 in the Middle East and North Africa: Systematic review, meta-analyses, and meta-regressions

Herpes simplex virus type 2 (HSV-2) infection is a prevalent, sexually transmitted infection with poorly characterized prevalence in the Middle East and North Africa (MENA) region. This study characterized HSV-2 epidemiology in MENA. HSV-2 reports were systematically reviewed as guided by the Cochrane Collaboration Handbook and findings were reported following PRISMA guidelines. Random-effects meta-analyses and meta-regressions were performed to estimate pooled mean outcome measures and to assess predictors of HSV-2 antibody prevalence (seroprevalence), trends in seroprevalence, and between-study heterogeneity. In total, sixty-one overall (133 stratified) HSV-2 seroprevalence measures and two overall (four stratified) proportion measures of HSV-2 detection in laboratory-confirmed genital herpes were extracted from 37 relevant publications. Pooled mean seroprevalence was 5.1% (95% confidence interval [CI]: 3.6%–6.8%) among general populations, 13.3% (95% CI: 8.6%–18.7%) among intermediate-risk populations, 20.6% (95% CI: 5.3%–42.3%) among female sex workers, and 18.3% (95% CI: 3.9%–39.4%) among male sex workers. Compared to Fertile Crescent countries, seroprevalence was 3.39-fold (95% CI: 1.86–6.20) and 3.90-fold (95% CI: 1.78–8.57) higher in Maghreb and Horn of Africa countries, respectively. Compared to studies published before 2010, seroprevalence was 1.73-fold (95% CI: 1.00–2.99) higher in studies published after 2015. Pooled mean proportion of HSV-2 detection in genital herpes was 73.8% (95% CI: 42.2%–95.9%). In conclusion, MENA has a lower HSV-2 seroprevalence than other world regions. Yet, 1 in 20 adults is chronically infected, despite conservative prevailing sexual norms. Seroprevalence may also be increasing, unlike other world regions. Findings support the need for expansion of surveillance and monitoring of HSV-2 infection in MENA.This work was supported by the Qatar National Research Fund [NPRP 9-040-3-008] and by pilot funding from the Biomedical Research Program at Weill Cornell Medicine in Qatar

HIV-related travel restrictions: trends and country characteristics

Introduction: Increasingly, HIV-seropositive individuals cross international borders. HIV-related restrictions on entry, stay, and residence imposed by countries have important consequences for this mobile population. Our aim was to describe the geographical distribution of countries with travel restrictions and to examine the trends and characteristics of countries with such restrictions. Methods: In 2011, data presented to UNAIDS were used to establish a list of countries with and without HIV restrictions on entry, stay, and residence and to describe their geographical distribution. The following indicators were investigated to describe the country characteristics: population at mid-year, international migrants as a percentage of the population, Human Development Index, estimated HIV prevalence (age: 15–49), presence of a policy prohibiting HIV screening for general employment purposes, government and civil society responses to having non-discrimination laws/regulations which specify migrants/mobile populations, government and civil society responses to having laws/regulations/policies that present obstacles to effective HIV prevention, treatment, care, and support for migrants/mobile populations, Corruption Perception Index, and gross national income per capita. Results: HIV-related restrictions exist in 45 out of 193 WHO countries (23%) in all regions of the world. We found that the Eastern Mediterranean and Western Pacific Regions have the highest proportions of countries with these restrictions. Our analyses showed that countries that have opted for restrictions have the following characteristics: smaller populations, higher proportions of migrants in the population, lower HIV prevalence rates, and lack of legislation protecting people living with HIV from screening for employment purposes, compared with countries without restrictions. Conclusion: Countries with a high proportion of international migrants tend to have travel restrictions – a finding that is relevant to migrant populations and travel medicine providers alike. Despite international pressure to remove travel restrictions, many countries continue to implement these restrictions for HIV-positive individuals on entry and stay. Since 2010, the United States and China have engaged in high profile removals. This may be indicative of an increasing trend, facilitated by various factors, including international advocacy and the setting of a UNAIDS goal to halve the number of countries with restrictions by 2015

Incidence of HIV and hepatitis C virus among people who inject drugs, and associations with age and sex or gender: a global systematic review and meta-analysis

BACKGROUND: Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender.METHODS: In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions. We contacted authors of identified studies for unpublished or updated data. We included studies that estimated incidence by longitudinally re-testing people at risk of infection or by using assays for recent infection. We pooled incidence and relative risk (RR; young [generally defined as ≤25 years] vs older PWID; women vs men) estimates using random-effects meta-analysis and assessed risk of bias with a modified Newcastle-Ottawa scale. This study is registered with PROSPERO, CRD42020220884.FINDINGS: Our updated search identified 9493 publications, of which 211 were eligible for full-text review. An additional 377 full-text records from our existing database and five records identified through cross-referencing were assessed. Including 28 unpublished records, 125 records met the inclusion criteria. We identified 64 estimates of HIV incidence (30 from high-income countries [HICs] and 34 from low-income or middle-income countries [LMICs]) and 66 estimates of HCV incidence (52 from HICs and 14 from LMICs). 41 (64%) of 64 HIV and 42 (64%) of 66 HCV estimates were from single cities rather than being multi-city or nationwide. Estimates were measured over 1987-2021 for HIV and 1992-2021 for HCV. Pooled HIV incidence was 1·7 per 100 person-years (95% CI 1·3-2·3; I 2=98·4%) and pooled HCV incidence was 12·1 per 100 person-years (10·0-14·6; I 2=97·2%). Young PWID had a greater risk of HIV (RR 1·5, 95% CI 1·2-1·8; I 2=66·9%) and HCV (1·5, 1·3-1·8; I 2=70·6%) acquisition than older PWID. Women had a greater risk of HIV (RR 1·4, 95% CI 1·1-1·6; I 2=55·3%) and HCV (1·2, 1·1-1·3; I 2=43·3%) acquisition than men. For both HIV and HCV, the median risk-of-bias score was 6 (IQR 6-7), indicating moderate risk. INTERPRETATION: Although sparse, available HIV and HCV incidence estimates offer insights into global levels of HIV and HCV transmission among PWID. Intensified efforts are needed to keep track of the HIV and HCV epidemics among PWID and to expand access to age-appropriate and gender-appropriate prevention services that serve young PWID and women who inject drugs.FUNDING: Canadian Institutes of Health Research, Fonds de recherche du Québec-Santé, Canadian Network on Hepatitis C, UK National Institute for Health and Care Research, and WHO.</p

Incidence of HIV and hepatitis C virus among people who inject drugs, and associations with age and sex or gender: a global systematic review and meta-analysis

Background: Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender. Methods: In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions. We contacted authors of identified studies for unpublished or updated data. We included studies that estimated incidence by longitudinally re-testing people at risk of infection or by using assays for recent infection. We pooled incidence and relative risk (RR; young [generally defined as ≤25 years] vs older PWID; women vs men) estimates using random-effects meta-analysis and assessed risk of bias with a modified Newcastle–Ottawa scale. This study is registered with PROSPERO, CRD42020220884. Findings: Our updated search identified 9493 publications, of which 211 were eligible for full-text review. An additional 377 full-text records from our existing database and five records identified through cross-referencing were assessed. Including 28 unpublished records, 125 records met the inclusion criteria. We identified 64 estimates of HIV incidence (30 from high-income countries [HICs] and 34 from low-income or middle-income countries [LMICs]) and 66 estimates of HCV incidence (52 from HICs and 14 from LMICs). 41 (64%) of 64 HIV and 42 (64%) of 66 HCV estimates were from single cities rather than being multi-city or nationwide. Estimates were measured over 1987–2021 for HIV and 1992–2021 for HCV. Pooled HIV incidence was 1·7 per 100 person-years (95% CI 1·3–2·3; I2=98·4%) and pooled HCV incidence was 12·1 per 100 person-years (10·0–14·6; I2=97·2%). Young PWID had a greater risk of HIV (RR 1·5, 95% CI 1·2–1·8; I2=66·9%) and HCV (1·5, 1·3–1·8; I2=70·6%) acquisition than older PWID. Women had a greater risk of HIV (RR 1·4, 95% CI 1·1–1·6; I2=55·3%) and HCV (1·2, 1·1–1·3; I2=43·3%) acquisition than men. For both HIV and HCV, the median risk-of-bias score was 6 (IQR 6–7), indicating moderate risk. Interpretation: Although sparse, available HIV and HCV incidence estimates offer insights into global levels of HIV and HCV transmission among PWID. Intensified efforts are needed to keep track of the HIV and HCV epidemics among PWID and to expand access to age-appropriate and gender-appropriate prevention services that serve young PWID and women who inject drugs. Funding: Canadian Institutes of Health Research, Fonds de recherche du Québec–Santé, Canadian Network on Hepatitis C, UK National Institute for Health and Care Research, and WHO