Microcrystalline Cellulose (MCC) from Oil Palm Empty Fruit Bunch (EFB) Fiber via Simultaneous Ultrasonic and Alkali Treatment

In this study, microcrystalline cellulose (MCC) was extracted from oil palm empty fruit bunch (EFB) cellulose which was earlier isolated from oil palm EFB fibre. In order to isolate the cellulose, the chlorination method was carried out. Then, the MCC was prepared by simultaneous ultrasonic and alkali treatment from the isolated α-cellulose. Based on mass balance calculation, the yields for MCC obtained from EFB was 44%. For fiber characterization, it is observed that the chemical composition of the hemicellulose and lignin for all samples decreased while composition for cellulose increased. The structural property of the MCC was studied by X-ray diffraction (XRD) method and the result shows that the MCC produced is a cellulose-I polymorph, with 73% crystallinity

Micro structure and Fractography of Multiwalled Carbon Nanotube Reinforced Unsaturated Polyester Nanocomposites

In this study unsaturated polyester resin (UPR) was reinforced with different concentration of predispersed multiwalled carbon nanotube (MWCNT). The rheology, structural analysis, fracture behavior, morphology, and thermal analysis of nanocomposites were carried out as a function of MWCNT content. Shear thinning behavior exhibited distinguishable dispersion quality of 0.3 wt% MWCNT in UPR matrix. Structural analysis reveals that MWCNT enhanced the nucleation of nanocomposites. The crystallinity of nanocomposites was increased by 71% after incorporation of 0.3 wt% MWCNT. Bending strength (BS) and bending modulus (BM) of nanocomposites were increased as well as 0.3 wt% MWCNT exhibited crack shielding in nanocomposites.The glass transition (Tg) and melting transition (Tm) of nanocomposites was increased by 68C and 108C respectively as compare to neat UPR. Additionally thermal stability of 0.3 wt% MWCNT incorporated nanocomposites was significantly improved as compare to UPR and nanocomposites which contained 0.1 and 0.5 wt% MWCN

PREPARATION AND CHARACTERIZATION OF LOW MOLECULAR WEIGHT CHITOSAN WITH DIFFERENT DEGREES OF DEACETYLATION BY THE ACID HYDROLYSIS METHOD

Objective: The objective of this research is to prepare Low Molecular Weight Chitosan (LMWC) by the acid hydrolysis method, using dilute hydrochloric acid (2M). LMWC has superior properties compared to the High Molecular Weight Chitosan (HMWC), especially in terms of water solubility, antibacterial and antifungal properties. These could open new potential applications for LMWC in sectors such as the cosmetics, food, and pharmaceutical industries. Methods: In this work, the acid hydrolysis method was used to produce LMWC with different molecular weights starting from 500 kDa and 93% degree of deacetylations (DDA). The molecular weights of the produced grades were determined by applying Mark-Houwink equation while the %DDA was determined and verified by the use of the 1st derivative UV method and 1HNMR method, respectively. The depolymerization reactions were carried out with different time intervals to produce totally deacetylated LMWC of 30 kDa, 15 kDa, and 7.5 kDa. The LMWC was characterized by FTIR, XRD, and DSC to evaluate the functionality, microstructure and thermal properties. Results: The FTIR spectra revealed that there is no significant difference in the main skeletal structure of the LMWC and HMWC. On the other hand, the XRD and DSC results showed that the LMWC of different molecular weights and degrees of deacetylation are of semi-crystalline structure, similar to the HMWC. Conclusion: The obtained results showed that the used acid hydrolysis procedure can produce LMWC grades of desired specifications, yields, and quality which are suitable for use in different applications

Impact Modified Oil Palm Empty Fruit Bunch Fiber/Poly(Lactic) Acid Composite

In this study, composites were fabricated from oil palm empty fruit bunch fiber and poly(lactic) acid by extrusionn followed by injection moulding. Surface of the fiber was pre-treated by ultrasound in an alkali medium and treatment efficiency was investigated by scanning electron microscopy (SEM) analysis and Fourier transforms infrared spectrometer (FTIR). Effect of fiber treatment on composite was characterized by tensile strength (TS), tensile modulus (TM) and impact strength (IS). Furthermore, biostrong impact modifier was incorporated into the treated fiber composite to improve its impact properties. Mechanical testing showed an improvement of up to 23.5% and 33.6% respectively for TS and TM of treated fiber composite above untreated fiber composite. On the other hand incorporation of impact modifier led to enhancement of about 20% above the initial IS of the treated fiber composite

Lattice Discretization in Quantum Scattering

The utility of lattice discretization technique is demonstrated for solving nonrelativistic quantum scattering problems and specially for the treatment of ultraviolet divergences in these problems with some potentials singular at the origin in two and three space dimensions. This shows that lattice discretization technique could be a useful tool for the numerical solution of scattering problems in general. The approach is illustrated in the case of the Dirac delta function potential.Comment: 9 page

Producing different grades of chitosan oligomers

Chitosan, the second most abundant natural polymer used in the world after cellulose, it has attracted attention long time since it is a polycationic polymer and could be utilized in different applications especially in food, medical, and pharmaceutical fields. The major disadvantage of chitosan is its insolubility in water, while it is soluble in dilute acidic solutions such as hydrochloric acid and acetic acid. Low Molecular Weight Chitosan (LMWC) has superior properties compared to the High Molecular Weight Chitosan (HMWC), especially its water solubility in addition to the antibacterial and antifungal properties which will open new horizons for LMWC to different applications especially in the cosmetics, food, and pharmaceutical industries. LMWC could be produced from the native HMWC using different hydrolysis method such as acid hydrolysis, enzymatic hydrolysis, and oxidative hydrolysis using nitrous acid and hydrogen peroxide. In addition to the mechanical methods such as ultra-sonication and radiation. For the industrial scale depolymerization, the acid hydrolusis using diluted hydrochloric acid is preferred because it is considered simple and practical method and resulted in a very good yield up to approximately 85%, also the concentration of hydrochloric acid (2M) is considered less corrosive and aggressive effects compared with other methods. The produced LMWT grades were characterized by FTIR, NMR, and X-Ray Powder Diffraction. Also the molecular weight of each prepared grade was determined using the intrinsic method in addition to the lazer diffraction method, and the % degree of deacetylation was determined by the acid hydrolysis method. The obtained results of molecular weight determination showed that the prepared grades using 2M Hydrochloric acid depolymeraization are considered of narrow range of polydispersity, then by this method the major problem of the commercial chitosan, the polydispersity could be solved. On the other hand the obtained LMWC grades were fully deacetylated. In order to get grades with specific %DDA’s an acetylation reaction could be carried out using different amounts of acetic anhydride. In this work LMWC in three molecular weight ranges were prepared ( Mwt< 5000, 10000 < Mwt < 20000, and 20000 < Mwt < 50000) and for each range we prepared three different degrees of deacetylation (100%DDA, 80%DDA, & 60%DDA)

Peristaltic Transport of a Couple Stress Fluid: Some Applications to Hemodynamics

The present paper deals with a theoretical investigation of the peristaltic transport of a couple stress fluid in a porous channel. The study is motivated towards the physiological flow of blood in the micro-circulatory system, by taking account of the particle size effect. The velocity, pressure gradient, stream function and frictional force of blood are investigated, when the Reynolds number is small and the wavelength is large, by using appropriate analytical and numerical methods. Effects of different physical parameters reflecting porosity, Darcy number, couple stress parameter as well as amplitude ratio on velocity profiles, pumping action and frictional force, streamlines pattern and trapping of blood are studied with particular emphasis. The computational results are presented in graphical form. The results are found to be in good agreement with those of Shapiro et. al \cite{r25} that was carried out for a non-porous channel in the absence of couple stress effect. The present study puts forward an important observation that for peristaltic transport of a couple stress fluid during free pumping when the couple stress effect of the fluid/Darcy permeability of the medium, flow reversal can be controlled to a considerable extent. Also by reducing the permeability it is possible to avoid the occurrence of trapping phenomenon

Characterization of microcrystalline cellulose isolated through mechanochemical method

Mechanochemical process, which involves simultaneous ultrasound and alkali treatment, has been used to isolatemicrocrystalline cellulose (MCC) from raw oil palm empty fruit bunch (REFB) fibre. Three steps have been used to preparethe MCC, namely removal of lignin, removal of hemicellulose and finally production of MCC. The crystallinity index inMCC is found to be 81% which is 54% higher than that of REFB and 45% higher than that of cellulose. Besidescrystallinity, the crystal size (28.03Å) of MCC is also enhanced noticeably by 53% as compared to the REFB and 28% ascompared to cellulose. The degradation temperature, and the residue content reveal the excellent thermal stability of MCCextracted through this mechanochemical technique

Fermion Doubling and a Natural Solution of the Strong CP Problem

We suggest the fermion doubling for all quarks and leptons. It is a generalization of the neutrino doubling of the seesaw mechanism. The new quarks and leptons are $SU(2)$ singlets and carry the electromagnetic charges of their lighter counterparts. An $SU(3)$ {\it anomaly free global symmetry} or a discrete symmetry can be introduced to restrict the Yukawa couplings. The form of mass matrix is belonging to that of Nelson and Barr even though our model does not belong to Barr's criterion. The weak CP violation of the Kobayashi-Maskawa form is obtained through the spontaneous breaking of CP symmetry at high energy scale. The strong CP solution is through a specific form of the mass matrix. At low energy, the particle content is the same as in the standard model. For a model with a global symmetry, in addition there exists a massless majoron.Comment: SNUTP 93-68, 19 pages 1 TeX figure, ReVTeX 3.

Preparation and characterization of low molecular weight chitosan with different degrees of deacetylation by the acid hydrolysis method

Objective: The objective of this research is to prepare Low Molecular Weight Chitosan (LMWC) by the acid hydrolysis method, using dilute hydrochloric acid (2M). LMWC has superior properties compared to the High Molecular Weight Chitosan (HMWC), especially in terms of water solubility, antibacterial and antifungal properties. These could open new potential applications for LMWC in sectors such as the cosmetics, food, and pharmaceutical industries. Methods: In this work, the acid hydrolysis method was used to produce LMWC with different molecular weights starting from 500 kDa and 93% degree of deacetylations (DDA). The molecular weights of the produced grades were determined by applying Mark-Houwink equation while the %DDA was determined and verified by the use of the 1st derivative UV method and1HNMR method, respectively. The depolymerization reactions were carried out with different time intervals to produce totally deacetylated LMWC of 30 kDa, 15 kDa, and 7.5 kDa. The LMWC was characterized by FTIR, XRD, and DSC to evaluate the functionality, microstructure and thermal properties. Results: The FTIR spectra revealed that there is no significant difference in the main skeletal structure of the LMWC and HMWC. On the other hand, the XRD and DSC results showed that the LMWC of different molecular weights and degrees of deacetylation are of semi-crystalline structure, similar to the HMWC. Conclusion: The obtained results showed that the used acid hydrolysis procedure can produce LMWC grades of desired specifications, yields, and quality which are suitable for use in different applications