The Effect of Pressing Temperature and Time on the Quality of Particle Board Made from Jatropha Fruit Hulls Treated in Acidic Condition

The high of pH of jatropha fruit hulls causes the negative properties of particleboard made from this material. Adjusting the  particle  acidity  and  pressing  conditions  (temperature  and  time)  is  among  the  technical  modifications  available  to improve this particleboard’s properties.  Particle acidity has been adjusted in a previous research project, and immersing the  particles  in  acetic  acid  was  found  to  be  the  best  treatment  in  this  preliminary  research.  In  order  to  improve  the particleboard’s  properties,  an  experiment  was  conducted  to  determine  the  best  pressing  temperature  and  time.  The objective of the research was to evaluate the influence of pressing temperature and time on the physical and mechanical properties of the board. Jatropha fruit hulls were immersed in 1% acetic acid solution for 24 hours. UF resin was used as the adhesive in the amount of 10%. The pressing temperatures and times used in this research were 110 °C, 120 °C, and 130 °C for 8 and 10  minutes, respectively. The particleboards  were tested to determine their physical and  mechanical properties according to JIS A 5908-2003. The result showed that pressing at 130 °C for 10 minutes resulted in the best physical  and  mechanical  properties.  Increasing  the  pressing temperature  at  a  constant  time  or  increasing  the  pressing time  at  a  constant  temperature  caused  the  particleboard  to  exhibit decreased  water  absorption.  The  thickness  swelling and modulus of elasticity (MOE) of the particleboard did not fulfil JIS A 5908-2003.Keywords: jatropha fruit hulls, particleboard, pressing temperature and tim

Surface Treatment of Fly Ash for Improving the Tensile Strength of Fly Ash/Unsaturated Polyester Composites

The  paper  presents  the  surface  treatment  of  fly  ashes  using  acid  and  alkali  solution  on  the  tensile  strength  of  the  fly ash/unsaturated  polyester  (UP)  composites.  Sulfuric  acid  (H2SO4),  hydrofluoric  acid  (HF)  and  sodium  hydroxide (NaOH) solution with concentration of 0%, 5%, 10%, 15%, and 20% (by weight) were used for surface treatment of fly ashes. Generally, the tensile strength of the treated fly-ash/UP composites shows a significant increase compared to the untreated  fly  ash.  Of  all  surface  treatments  studied,  the optimum  tensile  strength  was  obtained  at  a  concentration  of 10%.  At  this  concentration,  at  a  fly  ash  content  of  30%  (weight),  the  surface  treatment  using  NaOH  gave  the  highest tensile strength, approximately 18.69 MPa, or increased about 91% compared to the untreated fly ash. The morphology of fracture surfaces were evaluated using a scanning electron microscope (SEM). The fracture surfaces of the treated fly ash composite were rougher than that of the untreated fly ash indicating the improvement of the fly ashes-UP interaction.Keywords: composites, fly ash, surface treatment, tensile strength, unsaturated polyeste

Surface Modification of Graphite-Encapsulated Iron Compound Magnetic Nanoparticles by Radio Frequency Inductively-Coupled Plasma for Biomolecules Immobilization

We  proposed  the  graphite-encapsulated  iron  compound  magnetic  nanoparticles  as  a  candidate  of  nanomaterial  due  to their potential properties on physical, chemical and biological fields. This study  was performed in three steps, starting from  the  nanoparticle  fabrication,  nanoparticle  surface  modification  by  plasma  treatment,  leading  to  biomolecules immobilization for testing the treated nanoparticles capabilities. After the plasma treatment, the surface of the outmost graphene  layer  is  successfully  covered  by  nitrogen-containing  groups  definitively  assigned  by  XPS  spectra  and  the STEM-EDS  elemental  mapping.  The  nitrogen-containing  groups  formed  during  the  post-treatment  plasma  selectively attached on the outmost of graphene layer. The inner structure of inner graphene layer and the iron core are still found in  stable  condition  which  means  that  the  applied  plasma  condition  allows  the  efficient  covalent  functionalization  of nitrogen-containing group to the surface particles without give any destruction. The results shows the highest values of N/C atomic ratio of 5.4% is obtained by applying 10  min of  Ar plasma pre-treatment and 2  min of NH3 plasma post-treatment conducted in RF power of 80W and gas pressure of 50 Pa. Finally, in the biomolecules section, it is found that the  primary  amino  groups  grafted  after  Ar  plasma  pre-treatment  followed  by  NH3  plasma  post-treatment  appeared  to play  an  important  role  in  dextran  immobilization.  The  primary  amines  provide  a  high selective  reaction  between aldehyde group of oxidized dextran and amino groups of treated nanoparticles, hence the covalent immobilization was successfully  achieved.  The  dextran  immobilization  was  confirmed  by  XPS  and  HR-TEM  analysis  followed  by  amino group derivatization using TFBA. The deconvoluted peak at ~398.6 eV (C=N) (as an evidence for Schiff-base linkages between  dextran  and  amino  groups  on  the  treated  nanoparticles)  increased  with  the  increasing  of  the  dextran concentration. This result is consistent with the decrease of free amino group percentage remaining on the nanoparticles surfaces  which  was evidenced when the dextran concentration increased. High  magnification images obtained by HR-TEM allowed the visual observations of the differences between surface morphology of nanoparticles before and after dextran immobilization.Keywords: biomolecule immobilization, magnetic nanoparticles, surface modificatio

Microgrid Development Using A Grid Tie Inverter

The use of renewable energy sources (RES), especially photovoltaic (PV), to meet the demand of electrical energy has been  getting  a  great  deal  of  attention  as  an  alternative  solution  to  electrical  energy  deficit  problems.  RES  are  being applied  in  power  systems  in  a  variety  of  configurations  including  microgrid  systems.  One  of  the  characteristics  of  a microgrid  is  capability  to  supplying  power  to  grid  when  there  is  an  excess  power  to  supply  local  load.  This  research examines  the  chances  of  saving  power  consumption  from  grid  using  power  converters  grid  tie  inverter  (GTI)  in  a microgrid configuration. The test is done by using a zero load and power distribution methods. Test results show grid tie GTI  capable  of  supplying  electrical  power  to  grid  up  to  98%  of  the  input  power  converter.  In  the  microgrid configuration power usage from grid can be reduced up to 91%, which should be supplied from the grid to load.Keywords: architecture of microgrid, grid tie inverter (GTI), microgrid, Photovoltaic (PV

Semiconductor Thermal Neutron Detector

The  CdTe  and  GaN  detector  with  a  Gd  converter  have  been developed  and  investigated  as  a  neutron  detector  for neutron  imaging.  The  fabricated  Gd/CdTe  detector  with  the  25  mm  thick  Gd  was  designed  on  the  basis  of  simulation results  of  thermal  neutron  detection  efficiency  and  spatial  resolution.  The  Gd/CdTe  detector  shows  the  detection  of neutron  capture  gamma  ray  emission  in  the  155Gd(n,  g)156Gd,  157Gd(n,  g)158Gd  and  113Cd(n,  g)114Cd  reactions  and characteristic X-ray emissions due to conversion-electrons generated inside the Gd film. The observed efficient thermal neutron detection with the Gd/CdTe detector shows its promise in neutron radiography application. Moreover, a BGaN detector has also investigated to separate neutron signal from gamma-ray clearly. Keywords: detector, neutron, semiconductor, therma

The Effect Zeolite Addition in Natural Rubber Polypropylene Composite on Mechanical, Structure, and Thermal Characteristics

This  study  was  conducted  to  determine  the  effect  of  zeolite  as  filler  on  mechanical  properties,  and  thermal  structure  blends  of  natural  rubber  and  polypropylene  (NR/PP).  In  this  study, NR/PP/PP-g-MA  blends  was  filled  uncalcined zeolite and calcined zeolite at different weight percent of the 2, 4, and 6%. Samples were characterized to determine the tensile  strength,  fracture  elongation  and  Young's  modulus.  Structure  of  the  samples  was  investigated  using  XRD method and thermal characteristics were analyzed using DTA/TGA technique. The results obtained for tensile strength showed  a  significant  influence  with  the  addition  zeolite  of  the  NR/PP  blends  at  2%  by  weight  of  the  composition  (8 MPa) and decreased with increasing zeolite composition uncalcined zeolite or calcined zeolite. At 2% to 6% by weight of an increase in Young's modulus, for which uncalcined zeolite function more effectively than the calcined zeolite. On the  other  hand,  the  addition  of  uncalcined  zeolite  and  calcined  zeolite  did  not  result  in  decreased  fracture  elongation. The  XRD  analysis  zeolite  indicate  the  existence  of  amorphous  phase  and  crystalline  mineral  type  mordenite (CaAl2Si10O24.7  H2O).  In  general,  cristality  of  samples  filled  with  calcined  zeolite  slightly  higher  than  the  uncalcined zeolite  at  the  same  amount and  intercalation  occurs  between  the  zeolite  matrix  NR/PP.  Thermal  analysis  showed  that the samples are filled with calcined zeolite has a thermal resistance higher than the uncalcined zeolite, the melting point NR/PP 165.0 °C with the addition of 6 wt% zeolite melting point to 186.7 °CKeywords: mechanical, natural rubber, structure, thermal, zeolit

Synthesis of Tungsten Oxide Nanowires onto ITO Glass Using T-CVD

Tungsten oxide is an n-type semiconductor with interesting physical and chemical properties that make it suitable for various technological applications. Tungsten oxide nanowires were synthesized not only at low temperature but also without the use of any catalysts. The tungsten oxide nanowires were synthesized at 550 °C with tungsten layers onto the ITO glass using thermal chemical vapor deposition (T-CVD). The SEM image shows that the tungsten oxide nanowires are effectively grown with the 200 nm tungsten film. The Raman spectra shoulder at ~690 cm-1 proves the synthesized of tungsten oxide nanowires.Keywords: ITO glass, thermal chemical vapor deposition, Tungsten oxide nanowire

Recycling Roof Tile Waste Material for Wall Cover Tiles

Prior research on roof tile waste treatment has attempted to find the appropriate technology to reuse old roof tile waste by  create  wall  cladding  materials  from  it.  Through  exploration  and  experimentation,  a  treatment  method  has  been discovered  to  transform  the  tile  fragments  into  artificial  stone  that  resembles  the  shape  of  coral.  This  baked  clay artificial stone material is then processed as a decorative element for vertical surfaces that are not load-bearing, such as on the interior and exterior walls of a building. Before applying the fragments as wall tiles, several steps must be taken: 1)  Blunting,  which  changes  the  look  of  tile  fragments  using  a  machine  created  specifically  to  blunt  the  roof-tile fragment  edges,  2)  Closing  the  pores  of  the  blunted  fragments  as  a  finishing  step  that  can  be  done  with  a  transparent coat or a solid color of paint, 3) Planting the transformed roof-tile fragments on a prepared tile body made of concrete. In this study, the second phase is done using the method of ceramics glazing at a temperature of 700 °C. The finishing step is the strength of this product because it produces a rich color artificial pebble.Keywords: artificial coral, blunting, recycling, roof-tile waste, wall claddin

THE EFFECT OF RUBBER MIXING PROCESS ON THE CURING CHARACTERISTICS OF NATURAL RUBBER

This research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were  simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously added but using different type of fillers. In the fourth method, rubber was masticated for 3 minutes and then rubber chemicals and carbon black were subsequently added. The additions of rubber chemicals and carbon blacks to the masticated rubber were distinguished by the sequence and time allocated for each mixing process. The carbon blacks were added in two stages by which 10 phr was added first and the remaining 40 phr was added later along with oil. In another method, ratios of the carbon blacks addition (as done in the first  and the second stages) were 20:30, 30:20, and 40:10. The examination results showed that rubber mixing process gave an impact on the changes of curing characteristics. They were much affected by the method of carbon black addition. The mixing temperature also had an effect on both curing time and curing rate in which the higher the mixing temperature, the lower the curing time and curing rate. Vulcanization temperature also affected the curing time and curing rate in which the higher the vulcanization temperature, the lower the curing time and the higher the curing rate. Lastly, particle size of carbon black also gave an impact on the curing time and curing rate in which the smaller the particle size, the lower the curing time and the higher the curing rate.Keywords: curing characteristics, natural rubber, rubber mixing proces

DEVELOPMENT OF LOCAL-ECONOMIC-DEVELOPMENT SMALL AND MEDIUM INDUSTRIES (LED-SME) IN EAST JAVA

This paper presents the effects of Indonesian government’s developmental efforts of assistance and training performed on the growth of LED-SME business units and business performance. Both parameters of the government’s assistance and training were used to analyze the impact to the  growth and performance of business unit. To achieve a comprehensive result, samples acquired in this research were about 190 entrepreneurs and managers of LED-SME from East Java. Based on the parameters above, there are five hypotheses made to prove the relationship of the assistance and training to the growth and performance of business units. The structural equation modeling (SEM) was carried out to test the hypotheses. The results have shown that the government’s developmental efforts through both assistance and training for the LED-SME were capable on increasing growth and performance of business units. On the other hand, government’s developmental efforts through only trainings were incapable of directly affecting growth of LED-SME business units and performance. To improve the business unit and performance, the government needs to implement developmental principles of LED-SME with the basis of utilizing local natural resources and also the communities of LED-SME as main suppliers for their local markets. In addition, preservation and development of local cultural and traditional arts also need to be the government’s main concern. Keywords: government’s assistance and training, growth and performance of business uni