Novel conducting polymer current limiting devices for low cost surge protection applications

We report on the development of novel intrinsic conducting polymer two terminal surge protection devices. These resettable current limiting devices consist of polyaniline nanofibres doped with methane sulphonic acid electrochemically deposited between two 55 μm spaced gold electrodes. At normal applied voltages, the low resistance devices act as passive circuit elements, not affecting the current flow. However during a current surge the devices switch from ohmic to non-ohmic behaviour, limiting current through the device. After the current surge has passed, the devices reset back to their original state. Our studies show that a partial de-doping/re-doping process caused by the rapid diffusion of moisture out of or into the polymer film during joule heating/cooling is the underlying mechanism responsible

Pengembangan Model Peningkatan Daya Saing Gula Merah Untuk Memperkuat Ekonomi Masyarakat Pedesaan

Penelitian ini bertujuan untuk merumuskan model peningkatan daya saing gula merah sebagai upaya memperkuat ekonomi masyarakat pedesaan. Untuk mencapai tujuan penelitian digunakan metode PRA, FGD, RRA, indept interview dan survei. Sampel ditentukan melalui stratified random sampling sebanyak 150 orang. Teknik analisis data secara kuantitatif dan kualitatif. Analisis kuantitatif menggunakan DRCR dan PCR. Analisis kualitatif adalah fenomenologis dan pola kecenderungan yang dilakukan sepanjang rentang waktu penelitian. Penelitian dilakukan di dua kecamatan penghasil gula merah di Kabupaten Jember sejak bulan Pebruari 2016 sampai Juni 2016. Hasil penelitian pada agroindustri rumah tangga gula merah di Kabupaten Jember menunjukkan: (1) Keuntungan per 25 pohon/bulan sistem kemitraan Rp 1.014.575, sistem non mitra sebesar Rp 301.408 (skala kecil), Rp 668.113 (menengah) dan Rp 691.369 (besar); (2) pendapatan USAha gula merah/bulan sistem kemitraan Rp 4.426.688, sistem non mitra sebesar Rp 2.545.469 (skala kecil), Rp 3.467.260 (menengah) dan Rp 4.355.938 (besar), dengan kontribusi terhadap pendapatan total keluarga sebesar 94,36% pada sistem kemitraan, dan non mitra 85,83% (skala kecil), 90,52% (menengah) dan 93,36% (besar); (3) Daya saing kompetitif termasuk dalam kategori rendah (nilai PCR mitra= 0,84; non mitra skala menengah =0,92; besar = 0,90) bahkan skala kecil non mitra masuk dalam kategori sangat rendah (PCR =1,031); (4) Daya saing komparatif baik sistem kemitraan maupun non mitra termasuk dalam kategori sedang (nilai DRCR mitra = 0,65; non mitra skala kecil= 0,72; menengah= 0,70; besar= 0,67)

Synthetic, Spectroscopic And Antibacterial Studies Of Fe(II),Co(II),Ni(II),Cu(II),and Zn(II)Mixed Ligand Complexes Of Nicotinamide And Cephalexin antibiotics

Mixed  ligand complexes of bivalent metal  ions, viz; M= Co(II), Ni(II), Cu(II) and Zn(II) of  the composition [M(Ceph)(NA)3]Cl  in 1:1:3  molar  ratio,  (where  Ceph = Cephalexin  and NA = Nicotinamide have  been  synthesized and  characterized  by  repeated  melting  point  determination, Solubility, Molar conductivity, determination  the percentage of  the metal  in  the  complexes  by  flame(AAS),  FT-IR, magnetic  susceptibility  measurements  and  electronic  spectral  data.  The   ligands and  their metal complexes were  screened  for  their antimicrobial activity against  six bacteria(gram +ve) and (gram -ve). Key words:(Cephalexin antibiotics,Nicotinamide ,mixed ligand) Complexes,Antibacterial activities, and spectral studie

Preparation , Characterization and Antimicrobial activities of {Fe(II),Co(II),Ni(II),Cu(II),and Zn(II)}Mixed Ligand Complexes Schiff base derived from Cephalexin drug and 4(dimethylamino)benzaldehyde with Nicotinamide

New Schiff base ligand (Z)-7-(2-(4-(dimethylamino)benzylideneamino)-2-phenylacetamido)-3-methyl-8-oxo-5-thia-1-azabicyclo[4.2.0]oct-2-ene-2-carboxylic acid = (HL)was prepared via condensation of Cephalexin and 4(dimethylamino)benzaldehyde in methanol . Polydentate  mixed ligand  complexes were obtained from 1:1:2  molar ratio reactions with metal ions and HL, 2NA  on reaction with MCl2 .nH2O salt yields complexes corresponding to the formulas [M(L)(NA)2Cl] ,where M = Fe(II),Co(II),Ni(II),Cu(II),and Zn(II) and   NA=nicotinamide . The 1H-NMR, FT-IR, UV-Vis and elemental analysis were   used for the characterization of the ligand. The complexes were structurally studied through AAS, FT-IR, UV-Vis, chloride contents, conductance, and magnetic susceptibility measurements. All complexes are non-electrolytes in DMSO solution. Octahedral geometries have been suggested for each of the complexes. the Schiff base ligands function as tridentates and the deprotonated enolic form is preferred for coordination. In order to evaluate the effect ofthe bactericidal activity, these synthesized complexes, in comparison to the uncomplexed Schiff base has been screened against bacterial species., Staphylococcus aureus,Escherichia coil and the results are reported. Key words:(Cephalexin drug, Nicotinamide ,mixed ligand) Complexes, Antibacterial activities, and spectral studie

Inhibitory Effects of Chalcone on the Replication of Poliovirus in Vitro

The compound chalcon originally is extracted form some plant and herbs, the studies of the antiviral activity of this compound were done in two cell line cultures the L2OB and RD, the compound relatively non toxic to both cell lines of the concentration of 32?g/ml or less ,the compound have significantly anti poliovirus activity in both L2OB cell line and RD cell line, we find that the concentration of 0.03 ?g/ml or more inhibit the 100TCDID50 of the poliovirus .The therapeutic index(TI)used in this study to evaluate the drug activity ,( TI is the ratio of dose of drug which is just toxic to the cells to the does which is just inhibit the viral multiplication, if this index more than one the margin of safety of drug is according great ) .In this study the TI of chalcone against poliovirus is 266,therefore this compound if used in man have little or no side effect

Validasi Metode Penentuan Amonium Klorida dalam Obat Batuk Hitam secara Titrimetri

Amonium klorida merupakan zat aktif dalam obat batuk hitam yang berfungsi sebagai pengencer dahak. Penentuan kadar amonium klorida dalam sediaan obat menjadi sangat penting untuk uji kualitas produk agar obat memiliki khasiat dan keamanan yang dapat diterima pasien. Berdasarkan Farmakope V penentuan amonium klorida dapat dilakukan dengan metode argentometri. Analisis kadar amonium dalam obat batuk hitam secara argentometri belum tersedia data validasinya. Oleh karena itu perlu dilakukan validasi. Parameter validasi yang dijadikan acuan adalah akurasi, presisi, linearitas, batas deteksi dan nilai estimasi ketidakpastian pengukuran. Berdasarkan hasil yang diperoleh dalam penelitian parameter uji validasi untuk akurasi, ripitabilitas (%RSD), presisi antara (%RSD), linearitas (R2) dan estimasi ketidakpastian pengukuran secara berurutan yaitu sebesar 99,97-104,85%; 0,50-3,40%; 6,58%; 0,9985 dan 1,42 mg/5mL sehingga dapat disimpulkan bahwa metode penentuan amonium klorida dalam obat batuk hitam menggunakan metode titrasi argentometri belum cukup bukti untuk dinyatakan valid karena presisi atau keterulangan belum memenuhi syarat keberterimaan

Prevalence and management of oral health conditions among children with special health care needs

PURPOSE: To review the current evidence on the prevalence and management of oral health conditions among children with special health care needs (CSHCN). METHODS: A scoping review was selected as the most appropriate method of review for our main objective. The research question was defined as: For Special Health Care Needs Children, what is the prevalence of oral health conditions and how are the Special Health Care Needs Children be managed in dental setting? RESULTS: A total of 247 Studies were identified as of potential relevance. Following removal of duplicates (n = 11), 236 articles were screened in detail and 17 studies met the inclusion criteria. The articles included in this scoping review were published between 2000 and 2021. The ages ranged from birth to <21 years. The types of disabilities among children with special needs discussed in the chosen studies are Down syndrome, Autism Spectrum Disorder (ASD), Attention-Deficit/Hyperactivity Disorder (ADHD), Intellectual Disability (ID), Cerebral Palsy (CP), Ectodermal Dysplasia (ED), Asthma, Diabetes, Saethre-Chotzen Syndrome (SCS), Idiopathic Short Stature (ISS), Russel-Silver Syndrome (RSS), Growth Hormone Deficiency (GHD), Visual and Auditory Impairments. CONCLUSION: The results indicated that oral health conditions and poor oral health is worse among special needs children compared to children without special health care needs. This is a vital matter that should be addressed and considered by health care professionals and caregiver to help CSHCN to lead a better quality of life

Large dopant dependence of the current limiting properties of intrinsic conducting polymer surge protection devices

New two terminal surge protection devices based on intrinsic conducting polymers are demonstrated to be strongly affected by the dopant molecule type. Thermogravimetric analysis combined with current–voltage studies show a causal link between the dopant molecule, moisture content and the current limiting capability of the devices. Polyaniline thin-films with high moisture content produce devices with current saturation and foldback effects at high applied voltages while low moisture content films exhibit no current rectification and instead demonstrate decreasing resistivity with increasing voltage. Polyaniline doped with sulfuric acid (H2SO4) exhibited the largest moisture content and surge protection devices built with this material produced for the first time negative differential resistance under ambient conditions. A further improvement was made upon this through surface engineering of the interface between the polymer and electrodes using self-assembled monolayers

Mechanical properties of kenaf fibre thermoplastic polyurethane-natural rubber composites

Thermoplastic polyurethane-natural rubber TPUR-NR composites filled with treated and untreated kenaf fiber as filler were prepared at different TPUR and NR contents. The content of kenaf fiber was maintained at 12.5 wt % and the fiber was treated with 6 % solution of sodium hydroxide (NaOH), then dried for 24 hours in 100 °C, hot blended with polymer components, pulverized and pressed. The mechanical properties of the composites such as tensile, flexural and impact strength were determined, and their dependence on NaOH treatment of kenaf fibers was investigated. The analysis using scanning electron microscope (SEM) was implemented to identify the effect of alkali treatment on the microstructure of kenaf fiber and TPUR-NR composites. An improvement of fiber surface roughness and bonding between the fiber and polymer as well as an increase in impact energy and elongation at break of the composites was observed

Super hydrophobic SAM modified electrodes for enhanced current limiting properties in intrinsic conducting polymer surge protection devices

Surface interface engineering using superhydrophobic gold electrodes made with 1-dodecanethiol self-assembled monolayer (SAM) has been used to enhance the current limiting properties of novel surge protection devices based on the intrinsic conducting polymer, polyaniline doped with methanesulfonic acid. The resulting devices show significantly enhanced current limiting characteristics, including current saturation, foldback, and negative differential effects. We show how SAM modification changes the morphology of the polymer film directly adjacent to the electrodes, leading to the formation of an interfacial compact thin film that lowers the contact resistance at the Au−polymer interface. We attribute the enhanced current limiting properties of the devices to a combination of lower contact resistance and increased Joule heating within this interface region which during a current surge produces a current blocking resistive barrier due to a thermally induced dedoping effect caused by the rapid diffusion of moisture away from this region. The effect is exacerbated at higher applied voltages as the higher temperature leads to stronger depletion of charge carriers in this region, resulting in a negative differential resistance effec