5,320 research outputs found
Thermal comfort guidelines for production spaces within multi-storey garment factories located in Bangladesh
This research presents extensive field data on indoor thermal conditions along with workers' comfort votes taken at their workstations within three existing multi-storied garment factories during the three seasons (cool-dry, hot-dry and warm-humid) of Bangladesh. The main objective of the study was to observe the impact of thermal conditions on workers’ indoor thermal perception during each season of a year and from this identify thermal comfort guidelines (e.g. neutral temperatures, comfort ranges, preferred airspeeds and directions) to execute their production work comfortably. Subjective votes were collected from a total of 908 workers with the thermal data, physiological data and adaptive measures recorded simultaneously. Statistical analyses revealed that workers can accept a wider and relatively higher comfort range than the predicted band during cool-dry and hot-dry seasons, for instance, 22.7–29.1 °C and 22.3–30.4 °C respectively. A narrower comfort band (e.g. 28.7–30.9 °C), close to the predicted range, was found during the warm-humid season, which can be maintained by reducing radiant temperature and elevating airspeed. Further analyses indicated that workers prefer a mean airspeed of 0.3 m/s and comfort range of 0–3.0 m/s specific to their activities preferably from inlets located on south, north and east facades while upward and downward air movement, from for example ceiling fans, causes a rise of air temperature in the occupational zone and thermal discomfort. This research also suggested that the maximum distances of workstations from the ventilation inlets (windows) should be maintained at 12–18 m for sufficient cross ventilation, personal controls and adaptive opportunities to help maintain preferred thermal condition
Itinerant and local-moment magnetism in EuCr2As2 single crystals
We report on the crystal structure, physical properties, and electronic
structure calculations for the ternary pnictide compound EuCr2As2. X-ray
diffraction studies confirmed that EuCr2As2 crystalizes in the ThCr2Si2-type
tetragonal structure (space group I4/mmm). The Eu ions are in a stable divalent
state in this compound. Eu moments in EuCr2As2 order magnetically below Tm = 21
K. A sharp increase in the magnetic susceptibility below Tm and the positive
value of the paramagnetic Curie temperature obtained from the Curie-Weiss fit
suggest dominant ferromagnetic interactions. The heat capacity exhibits a sharp
{\lambda}-shape anomaly at Tm, confirming the bulk nature of the magnetic
transition. The extracted magnetic entropy at the magnetic transition
temperature is consistent with the theoretical value Rln(2S+1) for S = 7/2 of
the Eu2+ ion. The temperature dependence of the electrical resistivity
\r{ho}(T) shows metallic behavior along with an anomaly at 21 K. In addition,
we observe a reasonably large negative magneto-resistance (~ -24%) at lower
temperature. Electronic structure calculations for EuCr2As2 reveal a moderately
high density of states of Cr-3d orbitals at the Fermi energy, indicating that
the nonmagnetic state of Cr is unstable against magnetic order. Our density
functional calculations for EuCr2As2 predict a G-type AFM order in the Cr
sublattice. The electronic structure calculations suggest a weak interlayer
coupling of the Eu moments.Comment: 9 pages, 7 figure
Effect of changing window type and ventilation strategy on indoor thermal environment of existing garment factories in Bangladesh
This paper presents two workable solutions that can significantly improve the indoor thermal environment within workspaces in existing ready-made garment (RMG) factories in the tropical climatic context of Bangladesh. The research involved field studies in three multi-storey factory buildings, interviews with workers and owners and simulation studies. Field data indicated that the existing window configurations and limiting the ventilation strategy to occupied hours caused overheating of the indoor environment. Among a list of proposals, the building owners saw value in implementing two solutions (i.e. altering existing window type to one with a higher effective opening area and adopting a night-time ventilation strategy) in their existing buildings as well as proposed new buildings. To quantify the benefits, a validated simulation study was conducted. The findings confirm that these two interventions can provide reductions of up to 23% in overheated working hours and in so doing, improve workers’ thermal comfort and well-being
Valence Fluctuation in CeMo2Si2C
We report on the valence fluctuation of Ce in CeMoSiC as studied
by means of magnetic susceptibility , specific heat , electrical
resistivity and x-ray absorption spectroscopy. Powder x-ray
diffraction revealed that CeMoSiC crystallizes in
CeCrSiC-type layered tetragonal crystal structure (space group
\textit{P4/mmm}). The unit cell volume of CeMoSiC deviates from the
expected lanthanide contraction, indicating non-trivalent state of Ce ions in
this compound. The observed weak temperature dependence of the magnetic
susceptibility and its low value indicate that Ce ions are in valence
fluctuating state. The formal Ce valence in CeMoSiC
= 3.11 as determined from x-ray absorption spectroscopy
measurement is well bellow the value 3.4 in
tetravalent Ce compound CeO. The temperature dependence of specific heat
does not show any anomaly down to 1.8 K which rules out any magnetic ordering
in the system. The Sommerfeld coefficient obtained from the specific heat data
is = 23.4 mJ/mol\,K. The electrical resistivity follows the
behavior in the low temperature range below 35 K confirming a Fermi
liquid behavior. Accordingly both the Kadowaki Wood ratio and
the Sommerfeld Wilson ratio are in the range expected for
Fermi-liquid systems. In order to get some information on the electronic
states, we calculated the band structure within the density functional theory,
eventhough this approach is not able to treat 4f electrons accurately. The
non- electron states crossing the Fermi level have mostly Mo 4d character.
They provide the states with which the 4f sates are strongly hybridized,
leading to the intermediate valent state.Comment: 18 pages, 10 figures Submitted to Journal of Alloys and Compound
Valence fuctuation and magnetic ordering in EuNi2(P1-xGex)2 single crystals
Unusual phases and phase transitions are seen at the magnetic-nonmagnetic
boundary in Ce, Eu and Yb-based compounds. EuNiP is a very unusual
valence fluctuating Eu system, because at low temperatures the Eu valence stays
close to 2.5 instead of approaching an integer value. Eu valence and thus the
magnetic property in this system can be tuned by Ge substitution in P site as
EuNiGe is known to exhibit antiferromagnetc (AFM) ordering of
divalent Eu moments with = 30 K. We have grown
EuNi(PGe) (0.0 0.5) single crystals and
studied their magnetic, thermodynamic and transport properties. Increasing Ge
doping to 0.4 results in a well-defined AFM ordered state with = 12
K for = 0.5. Moreover, the reduced value of magnetic entropy for = 0.5
at suggests the presence of valance fluctuation/ Kondo effect in this
compound. Interestingly, the specific heat exhibits an enhanced Sommerfeld
coefficient upon Ge doping. Subsequently, electronic structure calculations
lead to a non-integral valence in EuNiP but a stable divalent Eu
state in EuNiGe which is in good agreement with experimental results.Comment: 7 pages, 8 figure
Interventions for promoting reintegration and reducing harmful behaviour and lifestyles in street-connected children and young people (Review)
Background
Millions of street-connected children and young people worldwide live or work in street environments. They are vulnerable to many risks, whether or not they remain connected to families of origin, and despite many strengths and resiliencies, they are excluded from mainstream social structures and opportunities.
Objectives
Primary research objectives
To evaluate and summarise the effectiveness of interventions for street-connected children and young people that aim to:
• promote inclusion and reintegration;
• increase literacy and numeracy;
• facilitate access to education and employment;
• promote mental health, including self esteem;
• reduce harms associated with early sexual activity and substance misuse.
Secondary research objectives
• To explore whether effects of interventions differ within and between populations, and whether an equity gradient influences theseeffects, by extrapolating from all findings relevance for low- and middle-income countries (LMICs) (Peters 2004).
• To describe other health, educational, psychosocial and behavioural effects, when appropriate outcomes are reported.
• To explore the influence of context in design, delivery and outcomes of interventions.
Interventions for promoting reintegration and reducing harmful behaviour and lifestyles in street-connected children and young people 1
(Review)
Copyright © 2016 The Cochrane Collaboration. Published by John Wiley & Sons, Ltd.
To explore the relationship between numbers of components and duration and effects of interventions.
• To highlight implications of these findings for further research and research methods to improve evidence in relation to the primary
research objective.
• To consider adverse or unintended outcomes.
Search methods
We searched the following bibliographic databases, searched for the original review, from inception to 2012, and various relevant non-governmental and organisational websites: Cochrane Central Register of Controlled Trials (CENTRAL); MEDLINE and PreMEDLINE;EMBASE and EMBASE Classic; Cumulative Index to Nursing and Allied Health Literature (CINAHL); PsycINFO; Education Resource Information Center (ERIC); Sociological Abstracts; Social Services Abstracts; Social Work Abstracts; Healthstar; Latin American Caribbean Health Sciences Literature (LILACS); System for Grey literature in Europe (OpenGrey); ProQuest Dissertations and Theses; EconLit; IDEAS Economics and Finance Research; JOLIS Library Catalog of the holdings of the World Bank Group and International Monetary Fund (IMF) Libraries; British Library for Development Studies (BLDS); Google and Google Scholar. We
updated the search in April 2015 for the review update, using the same methods.
Selection criteria
This review includes data from harm reduction or reintegration intervention studies that used a comparison group study design; all were randomised or quasi-randomised studies. Studies were included if they evaluated interventions provided for street-connected children and young people, from birth to 24 years, in all contexts.
Data collection and analysis
Two review authors independently extracted data and assessed risk of bias and other factors presented in the Discussion and Summary quality assessment (Grades of Recommendation, Assessment, Development and Evaluation (GRADE)). We extracted data on intervention delivery, context, process factors, equity and outcomes, and grouped outcomes into psychosocial outcomes, risky sexual behaviours or substance use. We conducted meta-analyses for outcomes where the outcome measures were sufficiently similar. We evaluated other outcomes narratively.
Main results
We included 13 studies evaluating 19 interventions from high-income countries (HICs). We found no sufficiently robust evaluations conducted in low- and middle-income countries (LMICs). Study quality overall was low and measurements used by studies variable. Participants were classified as drop-in and shelter-based. No studies measured the primary outcome of reintegration and none reported on adverse effects.We found no consistent results on a range of relevant outcomes within domains of psychosocial health, substance misuse and sexually risky behaviours . Interventions evaluated consisted of time-limited therapeutically based programmes that proved no more effective than standard shelter or drop-in services and other control interventions used for most outcomes in most studies.
Favourable changes from baseline were reported for outcomes for most participants following therapy interventions and standard services. We noted considerable heterogeneity between studies and inconsistent reporting of equity data. No studies measured the primary outcome of reintegration or reported on adverse effects.
Authors’ conclusions
Analysis revealed no consistently significant benefit for focused therapeutic interventions compared with standard services such as dropin centres, case management and other comparable interventions for street-connected children and young people. Commonly available services, however, were not rigorously evaluated. Robust evaluation of interventions, including comparison with no intervention, would establish a more reliable evidence base to inform service implementation. More robust research is needed in LMICs to examine interventions for street-connected children and young people with different backgrounds and service needs
Ferromagnetic Ordering in CeIr2B2: Transport, magnetization, specific heat and NMR studies
We present a complete characterization of ferromagnetic system CeIr2B2 using
powder x-ray diffraction XRD, magnetic susceptibility chi(T), isothermal
magnetization M(H), specific heat C(T), electrical resistivity rho(T,H), and
thermoelectric power S(T) measurements. Furthermore 11B NMR study was performed
to probe the magnetism on a microscopic scale. The chi(T), C(T) and rho(T) data
confirm bulk ferromagnetic ordering with Tc = 5.1 K. Ce ions in CeIr2B2 are in
stable trivalent state. Our low-temperature C(T) data measured down to 0.4 K
yield Sommerfeld coefficient gamma = 73(4) mJ/molK2 which is much smaller than
the previously reported value of gamma = 180 mJ/molK2 deduced from the specific
heat measurement down to 2.5 K. For LaIr2B2 gamma = 6(1) mJ/molK2 which implies
the density of states at the Fermi level D(EF) = 2.54 states/(eV f.u.) for both
spin directions. The renormalization factor for quasi-particle density of
states and hence for quasi-particle mass due to 4f correlations in CeIr2B2 is
12. The Kondo temperature TK ~ 4 K is estimated from the jump in specific heat
of CeIr2B2 at Tc. Both C(T) and rho(T) data exhibit gapped-magnon behavior in
magnetically ordered state with an energy gap Eg ~ 3.5 K. The rho data as a
function of magnetic field H indicate a large negative magnetoresistance (MR)
which is highest for T = 5 K.While at 5 K the negative MR keeps on increasing
up to 10 T, at 2 K an upturn is observed near H = 3.5 T. On the other hand, the
thermoelectric power data have small absolute values (S ~ 7 {\mu}V/K)
indicating a weak Kondo interaction. A shoulder in S(T) at about 30 K followed
by a minimum at ~ 10 K is attributed to crystal electric field (CEF) effects
and the onset of magnetic ordering. 11B NMR line broadening provides strong
evidence of ferromagnetic correlations below 40 K.Comment: 10 pages, 11 figure
A novel software-defined networking controller: The Distributed Active Information Model (DAIM)
© 2018 Polish Academy of Sciences. All Rights Reserved. This paper presents a new OpenFlow controller: the Distributed Active Information Model (DAIM). The DAIM controller was developed to explore the viability of a logically distributed control plane. It is implemented in a distributed way throughout a software-defined network, at the level of the switches. The method enables local process flows, by way of local packet switching, to be controlled by the distributed DAIM controller (as opposed to a centralised OpenFlow controller). The DAIM ecosystem is discussed with some sample code, together with flowcharts of the implemented algorithms. We present implementation details, a testing methodology, and an experimental evaluation. A performance analysis was conducted using the Cbench open benchmarking tool. Comparisons were drawn with respect to throughput and latency. It is concluded that the DAIM controller can handle a high throughput, while keeping the latency relatively low. We believe the results to date are potentially very interesting, especially in light of the fact that a key feature of the DAIM controller is that it is designed to enable the future development of autonomous local flow process and management strategies
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