Abstract: The Bacterial Foraging Optimization (BFO) algorithm is inspired by the behavior of bacteria such as Escherichia coli or Myxococcus xanthus when searching for food, more precisely the chemotaxis behavior. Bacteria perceive chemical gradients in the environment, such as nutrients, and also other individual bacteria, and move toward or in the opposite direction to those signals. The application example considered as a case study consists in establishing the dependency between the reaction yield of hydrogels based on polyacrylamide and the working conditions such as time, temperature, monomer, initiator, crosslinking agent and inclusion polymer concentrations, as well as type of the polymer added. This process is modeled with a neural network which is included in an optimization procedure based on BFO. An experimental study of BFO parameters is performed. The results show that the algorithm is quite robust and can obtain good results for diverse combinations of parameter values.
Abstract: The Internet of Everything (IoE) presents today a very attractive and motivating field of research. It is basically based on Wireless Sensor Networks (WSNs) in which the routing task is the major analysis topic. In fact, it directly affects the effectiveness and the lifetime of the network. This paper, developed from recent works and based on extensive researches, proposes a taxonomy of routing protocols in WSNs. Our main contribution is that we propose a classification model based on nine classes namely application type, delivery mode, initiator of communication, network architecture, path establishment (route discovery), network topology (structure), protocol operation, next hop selection and latency-awareness and energy-efficient routing protocols. In order to provide a total classification pattern to serve as reference for network designers, each class is subdivided into possible subclasses, presented, and discussed using different parameters such as purposes and characteristics.
Abstract: The construction of Nitro -N-amino phenyl maleimide branches onto Cellulose acetate (CA) substrate by free radical graft copolymerization using benzoyl peroxide as initiator led to formation of highly thermal stable copolymers as shown from the results of gravimetric analysis (TGA). CA-g-2,4-dinitro amino phenyl maleimide exhibited higher thermal stability than the CA-g-4-nitro amino phenyl maleimide as shown from the initial decomposition temperature (To). This is due to the ability of nitro group to form hydrogen bonding with hydroxyl group of the glucopyranose ring which increases the crystallinity of polymeric matrix. The crystalline shapes representing the graft part are clearly distinct in the Emission scanning electron microscope (ESEM) morphology of the copolymer. A suggested reaction mechanism for the grafting process was also discussed.
Abstract: The structure-property relationship and initiator effect on bulk polymerized poly(methyl methacrylate) (PMMA)–oragnomodified layered silicate nanocomposites was investigated. In this study, we used 2, 2'-azobis (4-methoxy-2,4-dimethyl valeronitrile and benzoyl peroxide initiators for bulk polymerization. The bulk polymerized nanocomposites’ morphology was investigated by X-ray diffraction and transmission electron microscopy. The type of initiator strongly influences the physiochemical properties of the polymer nanocomposite. The thermal degradation of PMMA in the presence of nanofiller was studied. 5 wt% weight loss temperature (T5d) increased as compared to pure PMMA. The peak degradation temperature increased for the nanocomposites. Differential scanning calorimetry and dynamic mechanical analysis were performed to investigate the glass transition temperature and the nature of the constrained region as the reinforcement mechanism respectively. Furthermore, the optical properties such as UV-Vis and Total Luminous Transmission of nanocomposites are examined.
Abstract: Greater access to sanitation in developing countries is
urgent. However even though sanitation is crucial, overall budget
for sanitation is limited. With this budget limitation, it is important
to (1) allocate resources strategically to maximize impact and (2)
take into account communal agency to potentially be a source
for sanitation improvements. The Jodipan and Kesatrian Project
in Malang, Indonesia is an interesting alternative for solving the
sanitation problem in which resources were allocated strategically
and communal agency was also observed. Although the projects
initial goal was only to improve visually the situation in the slums,
it became a new tourist destination, and the economic benefit that
came with it had an effect also on the change of behavior of the
residents and the government towards sanitation. It also grew from
only including the Kesatrian Village to expanding to the Jodipan
Village in the course of less than a year. To investigate the success
of this project, in this paper a descriptive model will be used and
data will be drawn from intensive interviews with the initiators of the
project, residents affected by the project and government officials. In
this research it is argued that three points mark the success of the
project: (1) the strategic initial impact due to choice of location, (2)
the influx of tourists that triggered behavioral change among residents
and, (3) the direct economic impact which ensured its sustainability
and growth by gaining government officials support and attention for
more public spending in the area for slum development and sanitation
improvement.
Abstract: Superabsorbent polymers (SAPs) or hydrogels with three-dimensional hydrophilic network structure are high-performance water absorbent and retention materials. The in situ synthesis of metal nanoparticles within polymeric network as antibacterial agents for bio-applications is an approach that takes advantage of the existing free-space into networks, which not only acts as a template for nucleation of nanoparticles, but also provides long term stability and reduces their toxicity by delaying their oxidation and release. In this work, SAP/nanosilver nanocomposites were successfully developed by a unique green process at room temperature, which involves in situ formation of silver nanoparticles (AgNPs) within hydrogels as a template. The aim of this study is to investigate whether these AgNPs-loaded hydrogels are potential candidates for antimicrobial applications. Firstly, the superabsorbents were prepared through radical copolymerization via grafting and crosslinking of acrylamide (AAm) onto chitosan backbone (Cs) using potassium persulfate as initiator and N,N’-methylenebisacrylamide as the crosslinker. Then, they were hydrolyzed to achieve superabsorbents with ampholytic properties and uppermost swelling capacity. Lastly, the AgNPs were biosynthesized and entrapped into hydrogels through a simple, eco-friendly and cost-effective method using aqueous silver nitrate as a silver precursor and curcuma longa tuber-powder extracts as both reducing and stabilizing agent. The formed superabsorbents nanocomposites (Cs-g-PAAm)/AgNPs were characterized by X-ray Diffraction (XRD), UV-visible Spectroscopy, Attenuated Total reflectance Fourier Transform Infrared Spectroscopy (ATR-FTIR), Inductively Coupled Plasma (ICP), and Thermogravimetric Analysis (TGA). Microscopic surface structure analyzed by Transmission Electron Microscopy (TEM) has showed spherical shapes of AgNPs with size in the range of 3-15 nm. The extent of nanosilver loading was decreased by increasing Cs content into network. The silver-loaded hydrogel was thermally more stable than the unloaded dry hydrogel counterpart. The swelling equilibrium degree (Q) and centrifuge retention capacity (CRC) in deionized water were affected by both contents of Cs and the entrapped AgNPs. The nanosilver-embedded hydrogels exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus bacteria. These comprehensive results suggest that the elaborated AgNPs-loaded nanomaterials could be used to produce valuable wound dressing.
Abstract: During the past two decades, photoinitiated polymerization has been attracting a great interest in terms of scientific and industrial activity. The wide recognition of UV treatment in the polymer industry results not only from its many practical applications but also from its advantage for low-cost processes. Unlike most thermal curing systems, radiation-curable systems can polymerize at room temperature without additional heat, and the curing is completed in a very short time. The advantage of cationic UV technology is that post-cure can continue in the ‘dark’ after radiation. In this study, bio-based acrylated epoxidized soybean oil (AESO) was cured with UV radiation using radicalic photoinitiator Irgacure 184. Triarylsulphonium hexafluoroantimonate was used as cationic photoinitiator for curing of 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate. The effect of curing time and the amount of initiators on the curing degree and thermal properties were investigated. The thermal properties of the coating were analyzed after crosslinking UV irradiation. The level of crosslinking in the coating was evaluated by FTIR analysis. Cationic UV-cured coatings demonstrated excellent adhesion and corrosion resistance properties. Therefore, our study holds a great potential with its simple and low-cost applications.
Abstract: The Romanian multilingual dictionaries – also named polyglot, plurilingual or polylingual dictionaries, have known a slow yet constant development starting with the end of the 17th century, when the first such work is attested, to the present time, when we witness a considerable increase of the number of polyglot dictionaries, especially the terminological ones. This paper aims at analyzing the context in which the first Romanian multilingual dictionaries were issued, as well as and the organization and structure particularities of the first lexicographic works of this type. The irretrievable loss of some of these works as well as the partial conservation of others renders the attempt to retrace the beginnings of Romanian lexicography extremely difficult. The research methodology is part of a descriptive and analytical approach based on two types of sources, subject to contrastive analysis: the notes made by the initiators of lexicographic projects and the testimonies of their contemporaries, respectively, along with the specialized studies regarding the history of the old Romanian lexicography. The analysis of the contents has indicated that these dictionaries lacked a scientific apparatus in the true sense of the phrase, failed to obey unitary organizational criteria, being limited, most of the times, to mere inventories of words, where the Romanian term was assigned its correspondent in other languages. Motivated by practical reasons, the first multilingual dictionaries were aimed at the clerics their purpose being to ensure the translators’ fidelity towards the original religious texts, regarded as sacred.
Abstract: The objective of this study was to synthesize and
characterize the poly(alkenoic acid)s with different molecular
structures, use these polymers to formulate a dental cement
restorative, and study the effect of molecular structures on reaction
kinetics, viscosity, and mechanical strengths of the formed polymers
and cement restoratives. In this study, poly(alkenoic acid)s with
different molecular structures were synthesized. The purified
polymers were formulated with commercial Fuji II LC glass fillers to
form the experimental cement restoratives. The reaction kinetics was
studied via 1HNMR spectroscopy. The formed restoratives were
evaluated using compressive strength, diametral tensile strength,
flexural strength, hardness and wear-resistance tests. Specimens were
conditioned in distilled water at 37oC for 24 h prior to testing. Fuji II
LC restorative was used as control. The results show that the higher
the arm number and initiator concentration, the faster the reaction
was. It was also found that the higher the arm number and branching
that the polymer had, the lower the viscosity of the polymer in water
and the lower the mechanical strengths of the formed restorative. The
experimental restoratives were 31-53% in compressive strength, 37-
55% in compressive modulus, 80-126% in diametral tensile strength,
76-94% in flexural strength, 4-21% in fracture toughness and 53-96%
in hardness higher than Fuji II LC. For wear test, the experimental
restoratives were only 5.4-13% of abrasive and 6.4-12% of attritional
wear depths of Fuji II LC in each wear cycle. The aging study also
showed that all the experimental restoratives increased their strength
continuously during 30 days, unlike Fuji II LC. It is concluded that
polymer molecular structures have significant and positive impact on
mechanical properties of dental cement restoratives.
Abstract: Chitosan polyacrylic acid composite membranes were
prepared by a bulk polymerization method in presence of N, N'-
methylene bisacrylamide (crosslinker) and ammonium persulphate as
initiator. Membranes prepared from this copolymer in presence and
absence of Ag nanoparticles were characterized by measuring
mechanical and physical properties, water up-take and antibacterial
properties. The results obtained indicated that the prepared
membranes have antibacterial properties which increase with adding
Ag nanoparticles.
Abstract: Superabsorbent polymers received much attention and
are used in many fields because of their superior characters to
traditional absorbents, e.g., sponge and cotton. So, it is very
important but challenging to prepare highly and fast-swelling
superabsorbents. A reliable, efficient and low-cost technique for
removing heavy metal ions from wastewater is the adsorption using
bio-adsorbents obtained from biological materials, such as
polysaccharides-based hydrogels superabsorbents. In this study, novel multi-functional superabsorbent composites
type semi-interpenetrating polymer networks (Semi-IPNs) were
prepared via graft polymerization of acrylamide onto chitosan
backbone in presence of gelatin, CTS-g-PAAm/Ge, using potassium
persulfate and N,N’-methylene bisacrylamide as initiator and
crosslinker, respectively. These hydrogels were also partially
hydrolyzed to achieve superabsorbents with ampholytic properties
and uppermost swelling capacity. The formation of the grafted
network was evidenced by Fourier Transform Infrared Spectroscopy
(ATR-FTIR) and Thermogravimetric Analysis (TGA). The porous
structures were observed by Scanning Electron Microscope (SEM).
From TGA analysis, it was concluded that the incorporation of the Ge
in the CTS-g-PAAm network has marginally affected its thermal
stability. The effect of gelatin content on the swelling capacities of
these superabsorbent composites was examined in various media
(distilled water, saline and pH-solutions). The water absorbency was
enhanced by adding Ge in the network, where the optimum value was
reached at 2 wt. % of Ge. Their hydrolysis has not only greatly
optimized their absorption capacity but also improved the swelling
kinetic.These materials have also showed reswelling ability. We
believe that these super-absorbing materials would be very effective
for the adsorption of harmful metal ions from wastewater.
Abstract: In this research paper were investigated the main
regularities of a radical bromination reaction of decalin. There had
been studied the temperature effect, durations of reaction, frequency
rate of process, a ratio of initial components, type and number of the
initiator on decalin bromination degree.
There were specified optimum conditions of synthesis of a
perbromodecalin by the method of a decalin bromination. There are
developed the technological flowchart of receiving a
perbromodecalin and the mass balance of process on the first and the
subsequent loadings of components.
The results of research of antibacterial and antifungal activity of
synthesized bromoderivatives have been represented.
Abstract: Biopolymers have gained much attention as ecofriendly alternatives to petrochemical-based plastics because they are biodegradable and can be produced from renewable feedstocks. One class of biopolyester with many potential environmentally
friendly applications is polylactic acid (PLA) and polycaprolactone (PCL). The PLA/PCL biodegradable copolyesters were synthesized by bulk ring-opening copolymerization of successively added Llactide (LL) and ε-caprolactone (CL) in the presence of toluene, using 1-hexanol as initiator and stannous octoate (Sn(Oct)2) as catalyst. Reaction temperature, reaction time and amount of catalyst were evaluated to obtain optimum reaction conditions. The results showed that the %conversion increased with increases in reaction temperature and reaction time, but after a critical amount of catalyst was reached the %conversion decreased. The yield of PLA/PCL biopolymer achieved 98.02% at the reaction temperature 160 °C, amount of catalyst 0.3 mol% and reaction time of 48 h. In addition, the thermal properties of the product were determined by differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA).
Abstract: Homogeneous graft copolymerization of methyl methacrylate (MMA) onto cellulose was carried out in N, N – dimethyl acetamide/LiCl (DMAc/LiCl) and dimethyl sulfoxide/ paraformaldehyde (DMSO/PF) solvent system taking ceric ammonium nitrate (CAN), benzoyl peroxide (BPO) and tin (II)-2-ethyl hexanoate [Sn(Oct)2] as initiators. Different grafting parameters like graft yield (GY), grafting efficiency (GE) and total conversion of monomer to polymer (TC) were evaluated at different reaction conditions of temperature, time, and variation of the amount of monomer and initiator. The viscosity average molecular weight of grafted PMMA and number of grafts per cellulose chain were also calculated. The products were characterized by FT-IR and 1H-NMR analyses and possible reaction mechanisms were deduced. Thermal degradation of the grafted products was also studied by thermo-gravimetric analysis (TG) and differential thermo-gravimetry (DTG).
Abstract: Constant amplitude fatigue crack growth (FCG) tests
were performed on dissimilar metal welded plates of Type 316L
Stainless Steel (SS) and IS 2062 Grade A Carbon steel (CS). The
plates were welded by TIG welding using SS E309 as electrode. FCG
tests were carried on the Side Edge Notch Tension (SENT)
specimens of 5 mm thickness, with crack initiator (notch) at base
metal region (BM), weld metal region (WM) and heat affected zones
(HAZ). The tests were performed at a test frequency of 10 Hz and at
load ratios (R) of 0.1 & 0.6. FCG rate was found to increase with
stress ratio for weld metals and base metals, where as in case of
HAZ, FCG rates were almost equal at high ΔK. FCG rate of HAZ of
stainless steel was found to be lowest at low and high ΔK. At
intermediate ΔK, WM showed the lowest FCG rate. CS showed
higher crack growth rate at all ΔK. However, the scatter band of data
was found to be narrow. Fracture toughness (Kc) was found to vary
in different locations of weldments. Kc was found lowest for the
weldment and highest for HAZ of stainless steel. A novel method of
characterizing the FCG behavior using an Infrared thermography
(IRT) camera was attempted. By monitoring the temperature rise at
the fast moving crack tip region, the amount of plastic deformation
was estimated.
Abstract: WikID is a wiki for industrial design engineers. An
important aspect for the viability of a wiki is the loyalty of the user
community to share their information and knowledge by adding this
knowledge to the wiki. For the initiators of a wiki it is therefore
important to use every aspect to stimulate the user community to
actively participate. In this study the focus is on the styling of the
website. The central question is: How could the WikID website be
visually designed to achieve a user experience which will incite the
user to actively participate in the WikID community? After a
literature study on the influencing factors of a website, a new
interface has been designed by applying the rules found, in order to
expand this website-s active user community. An online
questionnaire regarding the old or the new website gave insights in
the opinions of users. As expected, the new website was rated more
positively than the old website. However, the differences are limited.
Abstract: In this article, we synthesize a novel chitosan -based
superabsorbent hydrogel via graft copolymerization of mixtures
acrylic acid (AA) and N-vinyl pyrollidon onto chitosan backbones.
The polymerization reaction was carried out in an aqueous medium
and in the presence of ammonium persulfate (APS) as an initiator and
N,N'-methylene bisacrylamide (MBA) as a crosslinker.The hydrogel
structures were confirmed by FTIR spectroscopy. The swelling
behavior of these absorbent polymers was also investigated in
various salt solutions. Results indicated that the swelling capacity
decreased with an increase in the ionic strength of the swelling
medium. Furthermore, the swelling of superabsorbing hydrogels was
examined in solutions with pH values ranging between 1.0 and 13.0.
It showed a reversible pH-responsive behavior at pHs 2.0 and 8.0.
This on-off switching behavior makes the synthesized hydrogels as
an excellent candidate for controlled delivery of bioactive agents.
Abstract: detecting the deadlock is one of the important
problems in distributed systems and different solutions have been
proposed for it. Among the many deadlock detection algorithms,
Edge-chasing has been the most widely used. In Edge-chasing
algorithm, a special message called probe is made and sent along
dependency edges. When the initiator of a probe receives the probe
back the existence of a deadlock is revealed. But these algorithms are
not problem-free. One of the problems associated with them is that
they cannot detect some deadlocks and they even identify false
deadlocks. A key point not mentioned in the literature is that when
the process is waiting to obtain the required resources and its
execution has been blocked, how it can actually respond to probe
messages in the system. Also the question of 'which process should
be victimized in order to achieve a better performance when multiple
cycles exist within one single process in the system' has received
little attention. In this paper, one of the basic concepts of the
operating system - daemon - will be used to solve the problems
mentioned. The proposed Algorithm becomes engaged in sending
probe messages to the mandatory daemons and collects enough
information to effectively identify and resolve multi-cycle deadlocks
in distributed systems.
Abstract: Curing of paints by exposure to UV radiations is
emerging as one of the best film forming technique as an alternative
to traditional solvent borne oxidative and thermal curing coatings.
The composition and chemistry of UV curable coatings and role of
multifunctional and monofunctional monomers, oligomers, and
photoinitiators have been discussed. The limitations imposed by
thermodynamic equilibrium and tendency for acrylic double bond
polymerizations during synthesis of multifunctional acrylates have
been presented. Aim of present investigation was thus to explore the
reaction variables associated with synthesis of multifunctional
acrylates. Zirconium oxychloride was evaluated as catalyst against
regular acid functional catalyst. The catalyzed synthesis of glyceryl
acrylate and neopentyl glycol acrylate was conducted by variation of
following reaction parameters: two different reactant molar ratios-
1:4 and 1:6; catalyst usage in % by moles on polyol- 2.5, 5.0 and 7.5
and two different reaction temperatures- 45 and 75 0C. The reaction
was monitored by determination of acid value and hydroxy value at
regular intervals, besides TLC, HPLC, and FTIR analysis of
intermediates and products. On the basis of determination of reaction
progress over 1-60 hrs, the esterification reaction was observed to
follow 2nd order kinetics with rate constant varying from 1*10-4 to
7*10-4. The thermal and catalytic components of second order rate
constant and energy of activation were also determined. Uses of
these kinetic and thermodynamic parameters in design of reactor for
manufacture of multifunctional acrylate ester have been presented.
The synthesized multifunctional acrylates were used to formulate and
apply UV curable clear coat followed by determination of curing
characteristics and mechanical properties of cured film. The overall
curing rates less than 05 min. were easily attained indicating
economical viability of radiation curable system due to faster
production schedules
Abstract: In this article, we introduce a mechanism by which the same concept of differentiated services used in network transmission can be applied to provide quality of service levels to pervasive systems applications. The classical DiffServ model, including marking and classification, assured forwarding, and expedited forwarding, are all utilized to create quality of service guarantees for various pervasive applications requiring different levels of quality of service. Through a collection of various sensors, personal devices, and data sources, the transmission of contextsensitive data can automatically occur within a pervasive system with a given quality of service level. Triggers, initiators, sources, and receivers are four entities labeled in our mechanism. An explanation of the role of each is provided, and how quality of service is guaranteed.