Mm In Samples Research Articles

Study of the influence of hybrid filler on the strain sensitivity of nanocomposite material

The reflector of spacecraft is in operation in an open and folded position, so an urgent task is to develop strain gauges that determine the position of the reflector. The paper presents a study of the influence of a hybrid filler on the value of the strain resistance coefficient of a flexible strain-resistive element made of a nanocomposite material and describes the technological process of its manufacture using the vacuum infusion method. As a hybrid filler, a composition was used containing an electrically conductive component (carbon nanotubes) and a solid component (silicon carbide), which promotes uniform distribution of the filler in the polymer matrix. Using the rotational rheometer, the content of carbon nanotubes (CNTs) was determined at which the limiting level of viscosity for impregnation of glass fiber with a binder is achieved. The distribution features of the filler in the nanocomposite material were studied using a scanning electron microscope at the Krasnoyarsk Regional Center for Collective Use of the Federal Research Center KSC SB RAS. In the course of the work, the influence of the content of the hybrid filler on the tensoresistive properties of the nanocomposite material was determined. The maximum values of the tensor resistance coefficient were observed at the initial stage of the study (stretching 0.05 %): with a stretch of 0.1 mm with a total length of 200 mm for samples of nanocomposite material with a SiC hybrid filler of 1, 5 and 10 % and is 38, 40 and 40 The tensoresistance coefficient of nanocomposite material samples containing 1, 5 and 10 % SiC hybrid filler at maximum stretch (1 %) is about 19, 21 and 22, respectively.

Non-Destructive Testing of a Fiber-Web-Reinforced Polymethacrylimide Foam Sandwich Panel with Terahertz Time-Domain Spectroscopy.

Terahertz (THz) non-destructive testing can detect internal defects in dielectric materials. However, this technology is mainly used for detecting thin and simple structures at present, lacking validations for the detection effectiveness of internal defects in thicker and more complex structures, such as fiber-web-reinforced composite sandwich panels. In this study, samples of fiber-web-reinforced polymethacrylimide foam sandwich panels, which are, respectively, 20 mm and 30 mm thick, were made to detect the internal debonding, inclusion, pore, and crack defects by the THz time-domain spectroscopy system (THz-TDS). The peak-to-peak-imaging algorithm, maximum-amplitude-imaging algorithm, minimum-amplitude-imaging algorithm, pulse-width-imaging algorithm, and time-of-flight-imaging algorithm were used to process and image the collected THz signals. The results showed that the peak-to-peak-imaging algorithm had the best performance. To address the low imaging resolution of THz-TDS, a block-based super-resolution reconstruction method-SSSRGAN-is proposed, which can improve image resolution while maintaining the clear edge contours of defects. The defect-detection results of the samples showed that THz-TDS could detect all pore, debonding, and crack defects, with a minimum size of 3 mm for pores and debonding and a minimum thickness of 1 mm for cracks. The method showed poor detection performance for inclusions with a thickness of 0.053 mm, but could still extract the defect features. Based on the THz-TDS reflection mode measurement principle, the thickness information of the panel, foam core, and web of the samples was calculated: the measurement error was no more than 0.870 mm for Sample #1 and no more than 0.270 mm for Sample #2, demonstrating the accuracy of THz-TDS in measuring the dimensions of sandwich panel structures. In general, THz technology shows potential for detecting internal defects and performing dimensional measurements in complex structures. With the advancement of portable devices and enhancements in detection speed, real-time on-site detection is anticipated in the future.

Advances in analysis of microplastics in drinking water treatment plants. Fluorescence techniques using iDye Pink

Recently, the increasing amount of plastic waste has raised concerns about microplastics in aquatic environments. In this study, microplastics between 0.1 and 5 mm in samples from different points of three Drinking Water Treatment Plants (DWTP) were separated, quantified, and identified. Staining methods were used in combination with microscopic and spectroscopic techniques. On the one hand, the Rose Bengal dye was used to discriminate between natural and synthetic particles. On the other hand, Nile Red and iDye Pink reagents have been evaluated for staining microplastics, providing them with fluorescence. The nature of the particles is determined by comparison with a series of patterns by means of an epifluorescence microscope. In addition, "Micro Fourier Transform Spectrophotometer " and "Raman Spectroscopy" were used to identify the nature of the particles more accurately. Concerning the results, polyester was the most common material by fluorescence identification, and it was confirmed with Raman spectroscopy. Since most of the particles observed were microfibres, Raman proved to be a better identification technique than μ-FTIR, which could only identify large fragments. In addition, the global elimination of microplastics (MPs) resulted notable in the three DWTPs, being 81.47% for A, 88.98% for B, and 82.27% for C, thus guaranteeing a higher quality of drinking water.

Imaging optimisation process of human lung tissue using synchrotron radiation microcomputed tomography in PLS‐II

AbstractSynchrotron radiation microcomputed tomography (SR‐μCT) can provide non‐destructive three‐dimensional investigation for soft tissue with high resolution. The aim of this study is to evaluate technical improvements in microcomputed tomographic imaging of human lung tissue using a synchrotron radiation source at the 6C biomedical beamline. SR‐μCT images of excised human lung tissue (6 mm vertically and 10 mm horizontally sized) were explored at the 6C biomedical beamline in the Pohang accelerator laboratory (Pohang, Republic of Korea) using phase retrieval methods with a modified Bronnikov algorithm. Experimental data collection was performed with changes in the following conditions: the presence of a graphite attenuator, sample to detector distance, the presence of different scintillators and increasing pixel sizes. We identified that the resolution of lung tissue images was sufficiently enhanced when the graphite attenuator was not applied, 550 mm of sample to detector distance, with Cadmium tungsten (CdWO4) scintillator and twice binning of the pixel data and could be comparable with images from pathologic examination. Refinement of SR‐μCT techniques for soft tissue originating from the human body would advance the potential clinical application of synchrotron radiation in the near future.

Utilization and Conversion of Discarded Lobster Shells into Valuable Biopolymers - A Pilot Study

Chitin is one of the most abundant polysaccharides and can be made by combining shells of crabs, shrimp, lobsters, and fish. This study used discarded lobster shells as a raw material to produce a biopolymer. As part of the process, TiO2 was incorporated into the film in order to increase tensile strength. As compared to the control sample without TiO2 (3.34 MPa), the experimental sample with TiO2 showed improved tensile strength (3.96 MPa). Bio composites containing chitin and chitosan have been shown to produce thin, labile, textured films with good apparent textures. Upon tensile testing, it was determined that the material produced was sturdy enough for use as packaging and medical equipment. The prepared samples were analyzed in a variety of ways to understand their properties. In the FTIR analysis, it is evident that certain functional components are present that are responsible for the plasticity of the material. A study conducted on pathogenic Escherichia coli and Staphylococcus aureus indicated that the film had antimicrobial properties, as indicated by the zone of inhibition between 13 mm and 11 mm in samples with TiO2, respectively, and 11 mm and 10 mm in samples without TiO2. According to the physical degradation test, the produced biopolymer was 100% degraded when compared to a synthetic plastic (12%), which makes it the best choice for creating a multipurpose material. In addition to its biodegradability, biocompatibility, and anti-microbial properties, this material is suitable for use as biomedical interfaces and packaging materials.

Evaluation of the Performance of Two Australian Waste-Plastic-Modified Hot Mix Asphalts

The construction of hundreds of kilometres of roads around the world every year results in the consumption of large amounts of raw materials and the depletion of natural resources. In addition, technologically advanced countries such as Australia are currently facing a major issue regarding the waste materials produced daily by their citizens. The disposal of these waste materials is a critical issue faced by municipalities in modern cities. Currently, using waste materials in civil and construction engineering is of great interest to researchers and industry. This study investigates the impact of using waste polyethylene terephthalate to modify asphalt mixtures following Australian design guidelines and criteria. Different types of asphalt are used to investigate and determine the mechanical properties of modified asphalt mixtures. The Marshall stability, Marshall flow, Marshall quotient, and wheel-tracking tests were tested. The Marshall stability, Marshall flow, and MQ of the Marshall test results exhibited significant improvements when using PET in modified SMA and AC mixtures. It can be seen that the 8% PET produced a mixture with the highest stability of 19.78 kN. The lowest rut depth was about 2.08 mm for samples modified with 8% PET.

Laparoscopic Probe for Sentinel Lymph Node Harvesting Using Magnetic Nanoparticles.

Sentinel lymph node harvesting is an essential step in the surgical treatment of a growing number of malignancies. Various techniques are available to facilitate this purpose. The present study reports a new laparoscopic technique for lymph node harvesting using magnetic nanoparticles containing a superparamagnetic iron-oxide core and dextran coating. This study assesses the clinical relevance of the prototype and provides input for further technological development on the way to clinical implementation. A laparoscopic differential magnetometer prototype was built, utilizing a nonlinear detection principle (differential magnetometry) for magnetic identification of lymph nodes. The iron content sensitivity, depth & spatial sensitivity, and angular sensitivity were analyzed to investigate clinical options. The minimum detectable amount of iron was 9.8 μg at a distance of 1 mm. The detection depth was 5, 8, and 10 mm for samples containing 126, 252, and 504 μg iron, respectively. The maximum lateral detection distance was 5, 7, and 8 mm for samples containing 126, 252, and 504 μg iron, respectively. A sample containing 504 μg iron was detectable at all angulations assessed (0°, 30°, 60° and 90°). The laparoscopic differential magnetometer demonstrates promising results for further investigation and development towards laparoscopic lymph node harvesting using magnetic nanoparticles. The laparoscopic differential magnetometer facilitates a novel method for sentinel lymph node harvesting, which helps to determine prognosis and treatment of cancer patients.

Контроль дефектов в прошедшем через металл импульсном магнитном поле

Experimental dependences U (t) of electric voltage on time t, taken from an induction magnetic head (MG), moving relative to a magnetic carrier (MG) with records of the magnetic fields of defects of an aluminum object, are presented. Contact access to the surface of a metal object, above which there is a layer of air and solid dielectric in an arbitrary proportion and with a total thickness of more than 5 mm, is completely excluded. There is also no access to the rear side of the object, since it is a massive dielectric. The object with MN was exposed to a complex magnetic field pulse with a duration from 1 μs to 200 μs. The studies were carried out in a field that passed through the metal. Raster images of hidden holes with a diameter of 3 mm and 6 mm in layers of aluminum with a thickness of 0.67 mm of samples made up of layers of aluminum of different thickness and separated by layers of dielectric (air) were obtained. The thickness of the metal layers of the samples was 1.96 mm and 2.96 mm. The measurements were carried out in hard-to-reach places of the samples. The algorithm of the developed method was drawn up. The method allows to significantly increase the sensitivity and accuracy of the control of the parameters of defects and to carry out their control of areas of objects where control by other methods is impossible.

Remarkable microwave absorption of GO-SiO2/Fe3O4 via an effective design and optimized composition

We present the design, synthesis, and characterization of the graphene oxide (GO)-SiO2/Fe3O4 nanocomposite as well as its applications for microwave absorption. The GO-SiO2/Fe3O4 nanocomposites were synthesized with three different compositions having mass ratios (1:1), (1:2), and (1:3). Graphene oxide was synthesized by the modified Hummers’ method, while GO-SiO2 was hydrothermally synthesized, and GO-SiO2/Fe3O4 nanocomposites were obtained in a single pot process using different ratios of the mass of magnetite. Various characterization techniques were used to examine carefully the samples. SEM and TEM images show the creation of SiO2 and Fe3O4 nanoparticles on GO layers, which are confirmed by XRD. Next, we studied in detail the microwave absorption properties of all GO-SiO2/Fe3O4 composites. We have verified that GO-SiO2/Fe3O4 (1:3) with a high magnetic saturation of ∼70.5 emu g−1 and a corresponding layer thickness of 2 mm has excellent microwave absorption with a minimum reflection loss of −72.79 dB at 15.87 GHz and an effective absorption bandwidth (less than −10 dB) equal to 2.43 GHz (14.49–16.92 GHz). Besides, the maximum effective bandwidth reaches 7.54 GHz (10.46–18.0 GHz) and 7.39 GHz (10.61–18.0) for thicknesses of 3.2 mm and 3.6 mm in samples (1:2) and (1:1), respectively.

Oil Palm Wastes as Sustainable Sound Absorbing Particleboard

One method to absorb noise is by using acoustic absorber. Empty fruit bunch fibres (EFB) and mesocarp fibres (MF) are waste materials generated from palm oil mills. This research aimed to fabricate sustainable acoustic absorbing particleboard using EFB and MF to replace conventional materials currently used. Two parameters that were investigated are the mix ratio of the EFB and MF and the addition of binder (urea formaldehyde, UF) into the fibres. Sample thickness was maintained at 20 mm and 30 mm for samples with and without binder. The sound absorption coefficient (SAC) of the samples were tested using an impedance tube according to ISO 10534 – 2 standards. Samples produced using 50% EFB and 50% MF with and without binder shown the best SAC of 0.699 and 0.982 at 1200 Hz respectively. This is equal or better than conventional materials such as mineral wool with SAC values of 0.875 at 1000 Hz. Swelling test however shown that all samples do not meet the criteria by JIS A 5908 for particleboard. Future studies could include the use of green binder and different percentages of EFB, MF and binder.

Electrospun wound dressing as a promising tool for the therapeutic delivery of ascorbic acid and caffeine.

Aim: The aim of this work is to formulate a wound dressing for the delivery of ascorbic acid and caffeine. Method: A wound dressing was developed from electrospun nanofiber containing ascorbic acid and caffeine. In vitro drug release was performed at 25°C and 32°C. Wound healing activity of the nanofiber mats wastested in vivo using rat model with skin excision. Antifungal activity of the dressing was tested on Candida albicans using the disc diffusion method. Results & conclusion: Zone of inhibition was 6.7mm for caffeine dressing; however, inhibition zone increased to 16.7mm for samples containing both caffeine and ascorbic acid. Animals treated with ascorbic acid showed collagen deposition and very few fibroblast cells. Blood vessels and fibroblasts were increased in caffeine-loaded dressings compared with the ascorbic acid group. The findings of the present work suggest the benefits of topical ascorbic acid and caffeine for its high wound healing effects.

Association pattern between dimensions of fish and otolith to expedite morphometric variations of three geographically isolated stocks of Tenualosa ilisha (Hamilton, 1822) from diverse ecosystems

An attempt was made to establish association pattern between dimension of fish and otolith to expedite morphometric variations of geographically isolated stocks of Tenualosa ilisha (Hamilton, 1822), from three diverse ecosystems; viz., an estuarine (brackish water), a riverine (freshwater) and a lacustrine (freshwater) ecosystem. Sampling was carried out during the period from September 2017 to February 2019 and a total of 196 otoliths were sampled from Narmada Estuary (n=69), Brahmaputra River (n=75) and Ukai Reservoir (n=52) of India. Mean otolith length recorded was 3.55±0.14 mm, 5.18±0.09 mm and 3.85±0.07 mm for samples collected from Narmada Estuary, Brahmaputra River and Ukai Reservoir respectively. Otolith length-weight relationship (OLWR) from three ecosystems showed negative allometric b values ranging from 1.9046-2.5048, with significant difference between Narmada Estuary and Brahmaputra River (p<0.05). Power regression analysis of otolith dimensions (length and width) to total length of fish (TL) and otolith length (OL) to total weight of fish (TW) showed that data fitted well to the model as evident from R2 values (>0.6); except for relationship between otolith width (OB) and TL in samples from Brahmaputra River (R2=0.459). Present study provides first-hand information on association pattern of dimension of fish body and otolith of T. ilisha which can be used in geographical mapping of stock profile of the species.

Vibration Analysis of Uniform and Tapered Composite Beams with Embedded Shape Memory Alloy

In this study, laminated composite materials were hybridized with E-glass fiber and Nitinol (Nickel-Titanium) wires. Hand lay-up technique was used to prepare the samples, epoxy resin type (Sikadur 52 N) was used as matrix reinforced by one fiber from E-glass fiber woven roving with embedded nitinol wires with a diameter 0.5 mm for samples and number of wires such as 0, 1, 3, 5 and 9 to find the effect of the number of wires on the natural frequency. The samples were fixed as a cantilever beam. The effects of increasing the number of nitinol wires, the diameter of nitinol wires, the length of the cantilever beam and the thickness of beam on the natural frequencies of the beam were studied. Also, the effects of the tapered in width side and thickness side on the natural frequencies of cantilever beam were studied. The results showed that the increasing in the number of nitinol wires and the diameter of nitinol wires lead to decrease the natural frequency in martensite phase and increase the natural frequency in austenite phase. Also, the increasing in thickness of beam and width ratio of the beam lead to increase the natural frequency. As well as, the increasing in the thickness ratio leads to increase the first natural frequency and decrease the second and third ones. In addition, the increasing in the length of the beam decreases the natural frequency.

Comparison of bond strength of two porcelains and two base metal alloys in metal-ceramic restorations

The purpose of this study was to evaluate the bond strength between two porcelains (VITA VMK Master and VITA VM13) and two types of base metal alloys (Ceramill Sintron and Verabond). In an experimental study, 20 rectangular strips (25 mm × 4 mm × 0.5 mm) of each base metal alloy (Ceramill Sintron and Verabond) were fabricated according to the manufacturer's instructions. After sandblasting and polishing, the samples were placed in an ultrasonic device to remove surface contaminants. A surface of 8 mm × 4 mm × 1 mm of samples was veneered with Vita VM13 and VITA VMK Master. The samples were divided into four groups (n = 10 each group; VM13/Ceramill, VMK Master/Ceramill, VM13/Verabond, and VMK Master/Verabond), and bond strength was evaluated by three-point bending test with a universal testing machine. Two-way ANOVA was used for comparison in each group, post hoc Scheffe's test was used for analyzing data between groups, and the Kolmogorov-Smirnov test was used for the normality (P < 0.05). The maximum bond strength was related to Verabond/VM13 (44.35 ± 7.9 MPa) and then the Ceramill Sintron/VM13 (39.33 ± 4.43 MPa), and the lowest was related to the Ceramill Sintron/VMK Master (29.75 ± 3.2 MPa). There was no significant difference between bond strength of VM13 with the two alloy groups (P > 0.05), and bond strength of VMK Master to Ceramill Sintron CAD/CAM alloy was less than the conventional Verabond alloy (P < 0.05); however, bond strength of all the groups was above the standard threshold (25 MPa). Based on the results of this study, the bond strength of the porcelain to Verabond was better, but the bond strength of the porcelain to Ceramill Sintron also was not less than the standard threshold; thus, this new CAD/CAM alloy can be an alternative to the conventional base metal alloys in the metal-ceramic restorations.

MICROSTRUCTURAL AND MECHANICAL PROPERTIES AL 6061 PROCESSED BY COLD ROLLING AND AGING

An Alumunium alloy 6061was produced by cold rolling and subsequently aging. Cold rolling is used for reducing grain size and aging is used for producing second-phase, thus improving hardness, strength and wear resistance. In the present paper, a process through cold rolling with reduction of 50%, 60% and 70% in thickness then aged at 200 0 C for 1.800, 3.600, 5.400, 7.200 and 10.800 sec. Microstructural analysis shows that the grain morphology consists of equaxied grain for as-received samples and elongated grain for sample after cold roll and aging. X-Ray Diffraction (XRD) analysis showed peaks phases in Al 6061 after cold rolled and aging. Hardness measurements showed that combination between small grain size and presence of second-phase led to a significant increase in the hardness. Maximum hardness of 121 HBN is achieve for sample after cold roll 70% and aged for 5400 second. The wear resistance testing showed that lost particles of 6,209951 x 10 -6 mm 3 /mm for received sample and 4,775436 x 10 -6 mm 3 /mm for sample after aging process. It is showed that high hardness related to increase the wear resistance. It is reasonable that the presence of second phases are function as obstacle for dislocation movement.

Selective Distance-Based K+ Quantification on Paper-Based Microfluidics.

In this study, paper-based microfluidic devices (μPADs) capable of K+ quantification in aqueous samples, as well as in human serum, using both colorimetric and distance-based methods are described. A lipophilic phase containing potassium ionophore I (valinomycin) was utilized to achieve highly selective quantification of K+ in the presence of Na+, Li+, and Mg2+ ions. Successful addition of a suspended lipophilic phase to a wax printed paper-based device is described and offers a solution to current approaches that rely on organic solvents, which damage wax barriers. The approach provides an avenue for future alkali/alkaline quantification utilizing μPADs. Colorimetric spot tests allowed for K+ quantification from 0.1-5.0 mM using only 3.00 μL of sample solution. Selective distance-based quantification required small sample volumes (6.00 μL) and gave responses sensitive enough to distinguish between 1.0 and 2.5 mM of sample K+. μPADs using distance-based methods were also capable of differentiating between 4.3 and 6.9 mM K+ in human serum samples. Distance-based methods required no digital analysis, electronic hardware, or pumps; any steps required for quantification could be carried out using the naked eye.

Electrochemical, continuous-flow determination of p-benzoquinone on a gold nanoparticles poly(propylene-co-imidazole) modified gold electrode

ABSTRACTA novel continuous flow biosensor based on gold nanoparticles and poly(propylene-co-imidazole) was developed for the online determination of p-benzoquinone. The amperometric response was measured as a function of p-benzoquinone concentration at an applied potential of −50 mV. The hydrogen peroxide concentration was optimized and fixed at 1 mM in samples. The mass transfer resistance of the copolymer film was minimized, and the flow cell was regenerated quickly at 1 mL/min. The resulting device provided good analytical performance based on a linear dynamic range from 5–100 µM, a short response time of 3 s, a detection limit of 3.3 µM, excellent repeatability with a relative standard deviation of 0.82%, long-term stability of 95% after four weeks, and an accuracy of 105%. The gold nanoparticles enhanced the electron transfer rate on the electrode. The apparent Michaelis-Menten constant was 4 mM, showing that the enzyme retained catalytic specificity and provided high activity for p-benzoquinone.

Hand drawing of pencil electrodes on paper platforms for contactless conductivity detection of inorganic cations in human tear samples using electrophoresis chips.

This paper describes for the first time the fabrication of pencil drawn electrodes (PDE) on paper platforms for capacitively coupled contactless conductivity detection (C(4) D) on electrophoresis microchips. PDE-C(4) D devices were attached on PMMA electrophoresis chips and used for detection of K(+) and Na(+) in human tear samples. PDE-C(4) D devices were produced on office paper and chromatographic paper platforms and their performance were thoroughly investigated using a model mixture containing K(+) , Na(+) , and Li(+) . In comparison with chromatographic paper, PDE-C(4) D fabricated on office paper has exhibited better performance due to its higher electrical conductivity. Furthermore, the detector response was similar to that recorded with electrodes prepared with copper adhesive tape. The fabrication of PDE-C(4) D on office paper has offered great advantages including extremely low cost (< $ 0.004 per unit), reduced fabrication time (< 5 min), and minimal instrumentation (pencil and paper). The proposed electrodes demonstrated excellent analytical performance with good reproducibility. For an inter-PDE comparison (n = 7), the RSD values for migration time, peak area, and separation efficiency were lower than 2.5, 10.5, and 14%, respectively. The LOD's achieved for K(+) , Na(+) , and Li(+) were 4.9, 6.8, and 9.0 μM, respectively. The clinical feasibility of the proposed approach was successfully demonstrated with the quantitative analysis of K(+) and Na(+) in tear samples. The concentration levels found for K(+) and Na(+) were, respectively, 20.8 ± 0.1 mM and 101.2 ± 0.1 mM for sample #1, and 20.4 ± 0.1 mM and 111.4 ± 0.1 mM for sample #2.

Content of zinc in plants depending on its fractional composition in soil and properties of soil

Metals in soils occur in different forms, which are more or less mobile, which means bioavailable. The aim of this study was to assess the content of zinc in cultivated plants, depending on soil properties but also its content in soil and fractions in typical and unpolluted region, which is the Podlasie Province. The research material consisted of samples taken from arable soil in 81 points of Podlasie Province. Basic physicochemical properties and content of soil fraction < 0.02 mm in samples were determined. Pseudo-total content of zinc and its fractional composition in soil as well as zinc content in plants was evaluated. Correlation coefficients between the content of zinc in plants and physicochemical properties of soil were calculated. It was found that examined soil contained natural amount of zinc, characteristic for uncontaminated soils. The most of zinc was associated with the organic matter fraction and the least with residual fraction. Among the analysed plants from light soils, the most of zinc was found in rye. Plants from medium-heavy soils contained similar amount of zinc, with the exception of maize. Correlation coefficients do not confirm the significant relationship between soil properties and zinc in plants. Significant relationship was stated between bioaccumulation factors and the content of zinc in plants.

Oxalic acid pretreatment, fungal enzymatic saccharification and fermentation of maize residues to ethanol

Dilute oxalic acid pretreatment was investigated as a feasible method for conversion of maize residues into sugars and subsequent production of bioethanol. Oxalic acid concentration of 200 mM for samples treated at 160°C for 10 min was found to be the best pretreatment conditions. Cellulases, mainly cellobiohydrolases from Trichoderma reesei , recorded activities of up to 116 U/ml during saccharification of the cellulosic substrates. The optimum saccharification conditions using 0.2% (v/v) enzyme concentrate were the incubation temperature of 45°C for 48 h. Up to 46% (w/w) glucose and 28% (w/w) xylose were obtained from the pretreated maize residues (stalk, leaf, husk and cobs). Furthermore, a native Saccharomyces cerevisiae (strain KB) was able to convert 78% (w/w) of glucose (and other fermentable sugars) to ethanol after 60 h of incubation at 32°C, under stationary culture conditions. The challenges encountered in chemical and biological conversions included incomplete hydrolysis and fermentation due to substrate recalcitrance and the inability of the yeast cells to utilize 5-carbon sugars such as xylose. This study therefore provided baseline research data and information that could be used for more elaborate and scaled-up studies for possible industrial-scale conversion of the readily available crop residues into bioenergy. Key words : Bioethanol, cellulases, fermentation, hydrolysates, maize residues, oxalic acid, pretreatment, saccharification.