Bulk Density Tests Research Articles

Enhancing flowability of fine cohesive active pharmaceutical ingredients

Objective The effectiveness of pharmaceutical excipients and hydrophobic nano-silica as flow aid/regulator was studied and two active pharmaceutical ingredients, i.e. paracetamol and ibuprofen were used to gauge the effectiveness. Avicel PH-101 and Avicel PH-102 were chosen as pharmaceutical excipients and Aerosil R972 Pharma was used as hydrophobic nano-silica, the API’s and the excipients were micro-sized. Significance Fine powders lead to many operational difficulties in the pharmaceutical industry which need to be alleviated. The reliability and repeatability of the Powder Flow Tester need to be established. Methods Flow function, wall friction, and bulk density tests to gauge the said effect were conducted on Brookfield Powder Flow Tester. The samples for testing were prepared by blending (rigorous mixing) to ascertain the capability of inexpensive mixing in comparison to expensive blenders and machines. Results The study undertook shows that blending (rigorous mixing) was sufficient in improving the flow of active pharmaceutical ingredient powders. Blending with excipients Avicel PH-101 and Avicel PH-102 improved the flow substantially but the maximum improvement was seen in the nano blended samples. Conclusions The study conducted underlined the efficacy of the blending process by showing significant improvement in flow properties. The Powder Flow Tester confirmed the anticipated results of the powder blends indicative of its reliability. Moreover, repeatable results were obtained which established the repeatability of the instrument.

Engineering Properties of Paving stones made with Bamboo ash as a Partial Replacement for Cement

Agricultural and industrial wastes are recently being considered for recycling and reuse as likely replacements for cement in the production of concrete and paving stone. Bamboo ash was evaluated as a partial replacement for cement for the production of paving stones with the intent of reducing the carbon-di-oxide emission from cement; and also to enhance environment friendliness. Paving stone is used worldwide for road paving, external works of buildings and ancillary works of embankments and drains. This study investigated the effects of replacing 5, 10 and 15% cement with bamboo ash on the compressive strength of paving stone in a mix proportion of 1:1.38:2.73 and water-cement ratio of 0.4 while the paving stones were cured for 3, 7 and 28 days, respectively. Chemical composition, setting time and standard consistency tests were done on cement; specific gravity, moisture content and sieve analysis tests were performed on aggregates while slump, bulk density and compressive strength tests were conducted on the paving stone samples. Cement recorded a 25% standard consistency; with initial setting time of 23 minutes and final setting time of 276 minutes. Cement had 61.8% Calcium Oxide (CaO) and 21.2% Silicon Dioxide (SiO2) as its major oxide constituents while bamboo ash had 52.49% Silicon Dioxide (SiO2), 14.91% Calcium Oxide (CaO) and 12.71% Aluminium Oxide (Al2O3) as its major oxide constituents. The sand had specific gravity (SG) of 2.55 while the granite had SG of 2.73. The marginal reduction of the compressive strength of the modified bamboo ash paving stones from those of the plain paving stones at 5 % substitution of cement with bamboo ash was achieved.

Kajian pemalsuan bekatul dan tepung ikan di Wilayah Jawa Tengah

<p class="MDPI17abstract"><strong>Objective: </strong>The research aimed examine the quality adulteration of bran and fish meal in the Central Java region.</p><p class="MDPI17abstract"><strong>Methods: </strong>The materials used are rice bran and fish meal originating from 17 regions in Central Java which include Rembang, Jepara, Batang, Solo, Boyolali, Pekalongan, Kendal, Temanggung, Magelang, Ungaran, Pati, Purwodadi, Demak, Salatiga, Kudus, Klaten and Semarang. The research method uses descriptive method. Sampling was carried out by purposive random sample to represent the area of the area used as the research site (10 shops in 1 region with different districts and / or villages). Measurement of the parameters of adulteration on bran used Phloroglucinol test, buoyancy test and specific gravity test, while fish meal used urea test.<strong></strong></p><p class="MDPI17abstract"><strong>Results: </strong>The results showed that the bran which was tested for Phloroglucinol and positive buoyancy was faked by adding husks, and was found in the Pati and Demak areas. Density test describes rice bran with non-standard density in Purwodadi, Kendal, Temanggung, Demak and Semarang. Fish meal adulteration occurred in the Boyolali and Pati regions with positive urea content.<strong></strong></p><p><strong>Conclusions: </strong>The conclusion of this research is that good quality of rice bran based on phloroglucinol test, husk floating test and bulk density test were found in Rembang, Jepara, Solo, Boyolali, Magelang, Ungaran, Salatiga and Kudus areas, the quality of fish meal indicated for adulteration based on the urea test was Pekalongan and Purwodadi areas.</p>

Az őrlési idő fröccsöntött Al2O3-üveg kerámiatermékek tulajdonságaira gyakorolt hatásának vizsgálata

A kutatásban az őrlési idő fröccsöntött kerámiatermékek tulajdonságaira gyakorolt hatását vizsgáltuk, mivel a kerámiaiparban az egyik legfontosabb technológiai lépés az alapanyagok megfelelő szemcseméret-eloszlásának beállítása. Kísérleteink során különböző ideig (1 és 2 óra) őrölt korund-fritt keverékeket vizsgáltunk. Referencia anyagként kiinduló állapotban levő (őrlés nélküli) keveréket használtuk. A fröccsmasszát paraffin és olajsav felhasználásával készítettük el. A termékek minősítéséhez morfológiai, szemcseméret-eloszlás, testsűrűség, vízfelvétel, porozitás, valamint nyomó- szilárdság vizsgálatokat hajtottunk végre.

Study and characterisation of ancient terracotta ring well from pattaraiperumbudur, Tamil Nadu, India

This investigation is on the terracotta sample taken from the terracotta ring well expected to be built during the early historic period, excavates at Pattaraiperumbudur, Tamil Nadu, India. The study included heritage, architectural as well the civil aspects of the well. The sample was examined using Optical microscopy, Field Emission-Scanning Electron Microscopy with the aid of Energy dispersive X-Ray analysis, X-Ray Powder Diffraction, X-Ray Fluorescence, Fourier-transform infrared spectroscopy and Thermogravimetry / Differential Thermal Analysis to find the mineralogical composition, morphology and the temperature of firing of the sample. From X-Ray Powder Diffraction results it was clear that quartz and feldspar were in higher percentage in the sample, the images captured from the optical microscope also agrees with this. The firing temperature during the time of manufacture was found to be between 600 and 900 °C using the Field Emission-Scanning Electron Microscopy. The Thermogravimetry & Differential Thermal Analysis and Fourier-transform infrared spectroscopy results agrees with this. The physical properties of the sample were studied using water absorption, porosity and bulk density test which gave an idea about the less porous structure and thus lower burning temperature. From the X-Ray Fluorescence data it was found that the terracotta sample is non calcareous low refractory type. From the combined results it was clear that quartz and feldspar were in higher percentage in the sample and firing temperature during the time of manufacture was detected to be 600–900 °C. The 3-Dimentional drawing of the terracotta ring well was prepared for the accurate dimensions of the well. Exact age of the well the sample was determined to be approximately 2100 years by Optically Stimulated Luminescence test.

Inner defects elimination and significant reinforcement of rice straw/high‐density polyethylene composites by extractives removal process

AbstractThe effects on the internal defects of the rice straw (RS)/high‐density polyethylene (HDPE) composites are investigated by removing the extractives with cold water (CW), hot water (HW), and 1% alkaline (AL) solution. The characteristics of the RSs are measured by chemical composition, Fourier transform infrared, X‐ray diffractometry, scanning electron microscopy, thermogravimetric analysis, and bulk density testing. The three extractive removal methods change the surface features of the RS and increase the interphase adhesion between the RS and the HDPE matrix. As a result, the inner defects of the RS/HDPE composites are eradicated and the die swell phenomenon disappear. The flexural modulus, flexural strength, and impact strength of the final composites increase by 95.59, 83.29, and 154.79% in the HW extraction method. The CW and the AL extraction also significantly improve the static mechanical properties of the obtained RS/HDPE composites.

Properties of Sandcrete Block Produced with Coconut Husk as Partial Replacement of Sand

Sandcrete block is the most popular building material in construction industry. However, with the high and increasing cost of building materials experienced nowadays, it has been difficult to achieve affordable housing especially in developing countries. Also, significant dredging of sand for block production and the large amount of coconut husk thrown away as waste have increased the level of concern due to their adverse effect on environment. This work, therefore, sought to produce solid core sandcrete blocks in which sand component is partially replaced with coconut husk and investigate the suitability of using such blocks for building designs. The block samples produced using untreated and also treated coconut husks at various levels of sand replacement were subjected to bulk density, water absorption and compressive strength tests at 7 days and 28 days of curing. It was found that sand replacement with 20% of untreated coconut husk or 30% of treated coconut husk could yield a solid core sandcrete block suitable for non-load bearing walls of satisfactory performance. Since coconut husk is cheaply available, sustainable, and recyclable, utilising such promising material in this case can enhance production of cost-effective and optimally performing sandcrete blocks for building purposes. This will in turn help to boost the development of housing, minimise loss of agricultural lands, and reduce environmental pollution level, and so on.

Valorization of faecal and sewage sludge via pyrolysis for application as crop organic fertilizer

In developing countries, faecal sludge treatment facilities are non-existent in most cities and small towns resulting in untreated and improper disposal of sludge. In Ghana 85 % of faecal sludge produced each day is discharged into the earth with no effective treatment. Converting sewage and faecal sludge to biochar addresses the stigma of fertilizer obtained from human excreta, since the pyrolysis process guarantees a 100 % pathogen elimination, and enrich nutrients in faecal sludge biochar. The interest to convert sludge waste into biochar is that it ensures a pathogen free fertilizer. Sewage sludge and faecal sludge with sawdust were pyrolysed at different temperatures in this study. Sewage sludge (SSB1−300 °C, SSB2−450 °C and SSB3−600 °C) as well as faecal sludge with sawdust (CTB1−300 °C, CTB2−450 °C and CTB3−600 °C) were both converted to biochar at 300 °C, 450 °C and 600 °C, respectively using an electric kiln. Physicochemical parameters such as Total Nitrogen (TN), Total Potassium (TK), Total Phosphorous (TP), Calcium (Ca), Magnesium (Mg), Organic Carbon (OC), Organic Matter (OM), Cadmium (Cd), Arsenic (As), Ash content, pH, Electrical Conductivity (EC), Moisture content, Porosity and Bulk Density and germination test were performed. It was found that at 300 °C nitrogen content, organic matter, bulk density, biochar yield and moisture content were high, and longer root lengths were observed as well. Biochars produced at 450 °C produced the longest shoot lengths. Also, biochars produced at 600 °C had high phosphorous, potassium, calcium and magnesium levels, high porosity, pH and high heavy metal concentration as well. The outcomes demonstrate that biochars produced at higher temperatures are high in heavy metal concentration, but were within acceptable limits for application in agriculture. Biochar produced at moderately lower temperature is favourable for agriculture purposes. SSB1−300 °C, SSB2−450 °C, CTB1−300 °C and CTB2−450 °C had moderate pH and ash levels and so are less toxic to the growth of plants. Faecal sludge biochar produced at the three temperatures were suitable for use as fertilizer. The conversion of sludge waste into biochar will help improve faecal sludge management.

Determination of material and interaction properties of maize and wheat kernels for DEM simulation

The discrete element method (DEM) has become popular for modelling the behaviour of grain kernels during agricultural production, processing, and transportation. DEM simulations provide both qualitative and quantitative information on particle flow, which helps improve the understanding, design, and optimisation of grain handling equipment. The accuracy of the DEM models is greatly affected by the model input parameter values, such as the grain kernel material and interaction properties. However, precisely and properly quantifying these properties remains a challenging task due to the irregular shapes of kernels and the heterogeneity of these biological materials. In this study, the DEM simulation material and interaction properties of maize and wheat kernels were determined with a combination of direct measurements and calibration tests and validated against bulk material tests. The characterisation tests include X-ray micro-CT scanning for acquiring kernel size and shape information, the use of a reciprocating pin tribometer for coefficients of friction, and an inclined surface drop test for calibrating the coefficients of restitution. The measured model parameter values were used in DEM simulations of two common bulk material tests: the poured bulk density test and an angle of repose test. The percentage error of the bulk density test was 4.0% for maize and 8.4% for wheat, and the error in the angle of repose test was 0.4% for maize and 1.3% for wheat. DEM simulations of bulk density and angle of repose tests using the parameters measured with the characterisation tests are able to accurately predict the experimental measurements. • Material and interaction properties of maize and wheat were determined. • Glued-sphere particles were generated based on 3D scanned models. • A calibration test was developed to determine the coefficient of restitution. • Tribometer test provided measurements of the grain kernel friction coefficients. • Image analysis was used to quantitatively compare angles of repose.

Identification of channel diversion and bank protection techniques for toorsa river

This project aims for desigining of flood embankment structures to accommodate both normal flows as well as the highest designed flood for the return period of 100 years form flood frequency analysis. The new channel dimensions are being determined and embankment protection works for the floods are being designed and recommended. Having found steel sheet pile more advantages and safety, the same is recommended for the river training works. The focus of the project was confined to the channel diversion along with proper embankment works. The methodology included the usage of several approaches such as ARC –GIS to obtain catchment area and cross section of the river,and hydraulics analysis was done using HEC-RAS and the slope/W analysis check was done for the stability of the embankment works. The laboratory test such as sieve analysis, bulk density test, specific gravity test was done to determine the classification of the soil, compaction of the soil, to use different parameter for the desigini g works.

Assessment of molybdenum mine tailings as filler in cement mortar

The present study investigates the mechanical properties and durability of cement mortar incorporating molybdenum mine tailings as a filler material in an effort to report any suitable recycling potential. Molybdenum mine tailings are a type of mineral waste obtained from the mining industry. The proper disposal of mine tailings is an important challenge for sustainable mining practices. These fine-sized mine tailings (<300 μm) can be incorporated into building materials. Cement mortar specimens were fabricated with additions of 0% to 20% of molybdenum mine tailings. The mechanical behavior was observed by compressive strength, flexural strength, ultrasonic pulse velocity, dynamic modulus of elasticity, and bulk and apparent density tests. The durability behavior was tested by assessing the water absorption by immersion, total voids, water absorption by the capillary rise, and resistance to chemical (sulfate and acid) attacks. The addition of molybdenum mine tailings was found to be able to improve the performance of cement mortar according to all parameters examined here. The incorporation of 20% mine tailings resulted in 16% increase for 28 days mechanical performance while 10% mine tailings led to a 20% reduction in total voids in cement mortar. Furthermore, the mine tailings act as a buffer shield to resist aggressive chemical attacks. Based on the outcomes of the present study, the production of cement mortar containing molybdenum mine tailings is a viable solution for the recycling of these materials. Up to 10% molybdenum mine tailings can be used to produce masonry mortar with properties similar to that of conventional mortar.

Compressive Strength and Thermal Conductivity of Porous Mullite Ceramics

Porous ceramics are a form of ceramic material with widespread applications, such as filters, isolators, and acoustics. This research aimed to investigate the compressive strength and thermal conductivity of porous mullite ceramics (3Al2O3.2SiO2 or Si2Al6O13) produced using dry yeast powder as a PFA (pore-forming agent). Kaolin powder (Al2O3.2SiO4.2H2O or Al2Si2O5(OH)4) was used as a raw material for producing mullite ceramics. Kaolin powder and dry yeast powder were mixed at a variety of dry yeast powder weight fractions: 0%, 5%, 10%, 15%, 20%, and 25%. The composition was mixed using Turbula Mixer for 1 hour. The cylindrical green body (diameters of 12 mm, 15 mm, and 30 mm) of every constituent was formed by the uniaxial pressing method at 10 MPa. Monolithic kaolin was sintered at variable temperatures (1,100 oC, 1,200 oC, 1,300 oC, 1,400 oC, 1,450 oC) for 2 hours then subjected to several tests for its density. From the bulk density tests, it was found that the optimum temperature for 2-hour sintering was 1,450 oC. This temperature was then used for the sintering process of the kaolin specimens which contained dry yeast powder. Testing was performed on the microstructure, bulk density, burning waste in mass and volume, compressive strength, and thermal conductivity. According to the literature, kaolin will transform into mullite (3Al2O3.2SiO2 or Si2Al6O13) and cristobalite (SiO2) at 1,450 oC. It was found that with the increase in the content of dry yeast powder as PFA in the mixture with kaolin, the bulk density decreased (from 2.44 gr/cm3 to 1.521 gr/cm3), the porosity increased (from 23.77% to 52.48%), the compressive strength decreased (from 38.04 MPa to 4.51 MPa), and the thermal conductivity decreased (from 3.76 W/moC to1.34 W/moC), each from yeast powder content 0% to 25%.

Mechanical Characteristics of Asphalt Mixture Modified by Polypropylene Waste

Plastics are durable and inexpensive, making the levels of their production high in relation to other materials. Further, the plastics have a slow degradation process under normal conditions, and as a result they have a long life-time. These two factors have led to increasing the plastic waste, affecting, adversely, inhabitants and environment. Re-using plastic waste as additives can be viewed as one of the promising approaches to tackle this issue and, equally, can be considered a cheap way of improving many engineering materials. In the current paper, the effect of adding polypropylene (PP) waste to asphalt mixture (asphalt and aggregate) was explored. The exploration was made first by determining the best asphalt content (without polypropylene) and then investigating the effect of different percentages of PP waste on the performance of this optimal mix. The results showed that 5.5% (by mass) gives a good balance among the properties (flow value, stability and bulk density). Further, the results indicated that the PP waste has improved most asphalt mixture characteristics where bulk density and flow values tests pointed that 9% of PP is the best concentration.

A Sustainable Autoclaved Material Made of Glass Sand

Far-reaching technological progress, manufacturing, and rapidly advancing globalization dictate new conditions for the development and changes in the construction industry. Valorization of by-products and the use of secondary materials in the production of building materials have attracted a lot of attention. Silicate materials were assessed on the basis of their compressive property. An orthogonal compositional plan type 3k (with k = 2), that is, a full two-factor experiment was applied in order to carry out the compressive strength and bulk density tests. Glass sand was added to the silicate mass as a modification. The results show that the compressive strength was higher than that of traditional bricks. Scanning electron microscopy coupled with energy dispersive spectrometry SEM/EDS was used to study the microstructure, whereas the XRD analysis was applied to examine the structures. Laboratory tests were performed on samples with dimensions of 50 × 50 × 50 mm. The results show the bulk density increase to the value of 1.75 kg/dm3, which increases the acoustic performance of the new products. The results of the modifications also indicate changes in the structure of the new bricks. The reference sample contained α-quartz, zeolite, tobermorite 9A, and calcium aluminum silicate (Ca2Al4Si12O32), whereas the samples modified with glass sand, the presence of phases such as α-cristobalite, natrolite, tobermorite 11A, gyrolite, and analcite was recorded.

Manufacturing of polymer/metal composites by fused deposition modeling process with polyethylene

ABSTRACTIn this study, production of metal/polymer composites using polyethylene as the matrix with various contents of metal powder was investigated. Fused deposition modeling (FDM) process is one of the most popular and conventional additive manufacturing methods to produce three‐dimensional (3D) specimens from computer‐aided design data with complex geometry and lower prices in comparison with the alternative methods. Given the advantages of this process, it seems inevitable for the development of new materials. Utilizing semicrystalline plastics impose challenges for producing parts due to printing issues such as distortion and warpage. In this experimental work, a compounding production line was implemented to produce composite filaments with 25, 50, and 75 wt % of copper powder suitable for the FDM process. After dealing with printing issues, flexural, electrical conductivity, and bulk density tests were done. The micrographs of the specimens were examined via scanning electron microscopy to reveal the distribution of the copper particles. It is believed that the metal/polymer filament could be used to print new 3D parts. The material could be utilized in electromagnetic structures for some specific applications, such as shielding, with new properties. Also, by solving printing problems for a semicrystalline polymer, it can be encouraging to examine printing process for other rarely used thermoplastics. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48717.

Production of geopolymer composites by using different alkaline solution/material ratio

This study reports an experimental program to optimize mix design parameters of fly ash-based geopolymer engineering composites. Fly ash (FA) supplied from Çatalağzı Thermal Power Plant (Zonguldak, Turkey) and Rilem Cembureau Standard Sand were used together with a constant ratio of 0.50 for producing geopolymer. In the first step, two different alkaline solution/material ratio (FA+standard sand) (L/M) were determined as 0.20 and 0.40, respectively. After that, sodium silicate ((Na2SiO3) and 12M sodium hydroxide (NaOH) were utilized at a ratio of 1, 2, and 3, respectively. 6 mixtures obtained by using different design parameters were cured at 70 °C for 24 hours, respectively, and then they were stored at room temperature until testing age. While the physical properties of the samples were measured by the bulk density and water absorption tests at 28 days, mechanical properties were tested via the compressive and flexural strength tests at 90 days, respectively.The results indicated that the highest compressive strength for geopolymer materials was found as 36.5 MPa in the mixture produced with the ratios of L/M=0.2 and Na2SiO3/NaOH=2 (by weight). However, less alkali reaction caused by using excessive activator solutions decreased the strength characteristics of geopolymer.

Distribution of bulk unit weight of residual soils from the Northern Malaysia

A total of 284 bulk unit weight data were obtained from soil samples collected from 29 failed slopes and 10 stable slopes in Penang Island and Baling, Kedah. Both study areas are located in the Northern Malaysia. Field bulk density tests were performed at all the locations where disturbed soil samples were also collected to determine the other basic important properties of the residual soils. The highly variable values of bulk unit weight are due to the high complexity and variable formation of the residual soils. The objective of this research is to determine the best-fit distribution of the highly variable values of bulk unit weight of the soil taken from the stable slopes and failed slope especially in Northern Malaysia. This research also aims to determine the mean value of bulk unit weight of residual soils. The bulk unit weight data was tested based on Kolmogorov-Smirnov method using SPSS software, to check the normality of the data distribution. The best-fit distribution for the variation of bulk unit weight of the residual soils taken in the Northern Malaysia was normal distribution. The mean value was found to be 17.30 kN/m3. The range of bulk unit weight found here is within the range that was found by the earlier researchers.

Experimental investigation of modified bentonite clay-crumb rubber concrete

This study was carried out to investigate the effects of jointly replacing cement and sand with bentonite clay and crumb rubber on the engineering properties of 25 MPa concrete. The materials used for the study were cement, bentonite clay, sand, crumb rubber, stone and water. Microstructural formation, elemental compositions and crystalline phases of cement, bentonite clay, sand, crumb rubber and stone were determined by using Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS) and X-ray Diffraction (XRD) experiments respectively. Geotechnical properties of fine aggregates (sand and crumb rubber) and coarse aggregate (stone) were determined from sieve analysis, fineness modulus, moisture content, apparent relative density and bulk density experiments. Water samples were evaluated with pH and conductivity tests. Mechanical properties of the modified bentonite clay-crumb rubber concrete were evaluated with slump, bulk density, compressive strength and tensile splitting strength tests. The microstructural formation and elemental composition of the concrete were also evaluated with the aid of SEM and EDS respectively. The results revealed that the constituent materials possessed adequate engineering requirements for the production of concrete. The modified bentonite clay-crumb rubber concrete showed comparable mechanical and microstructural properties to that of plain concrete and can be suitable for the construction of driveways, floors and walkways.

The Bioenergetic Potential of Four Oak Species from Northeastern Mexico

Lack of knowledge regarding the fuel quality of diverse tree species prevents their use. Furthermore, the potential use of wood with the bark of different tree species for pellet production is still relatively unexplored in the scientific literature. In Mexico, the sawdust of Quercus genus (oak) is underutilized, despite it being an important forest resource, due to some anatomical and technological characteristics. The sawdust of Quercus with bark is also considered to have a low economic value. The objective of this study was to analyze the energy characteristics of barked and debarked Quercus sideroxyla, Q. rugosa, Q. laeta, and Q. conzattii in order to evaluate their potential for pellet production. Granulometric distribution, bulk density, proximal analysis, and calorific value tests were carried out. The sawdust of the four tree species studied was in accordance with the limits established by the standard EN 14961-2. Sawdust with a particle size of 0.425 mm had the highest percentage of retained mass (30.33%) (p &lt; 0.05) in the granulometry test. There were no statistical differences in granulometry (p &gt; 0.05) between barked and debarked sawdust for all Quercus species. Barked sawdust presented higher bulk density (p &lt; 0.05) than debarked sawdust (246 and 224 kg/m3, respectively). The moisture content did not show statistical differences (p &gt; 0.05) between barked and debarked sawdust. The volatile material was higher (p &lt; 0.05) in debarked sawdust (88.7%) than in barked sawdust (85.0%). The ash content was below 0.5%. The fixed carbon was higher (p &lt; 0.05) in barked sawdust (14.6%). The calorific value was higher (p &lt; 0.05) in barked sawdust and for the Q. rugosa species (19.5 MJ/kg). The results suggest that the oak species analyzed, both barked and debarked, showed good potential for pellet production. Future studies should quantify fuel quality for a variety of diameter distributions, and analyze pellet mechanical properties and ash slagging risk.

Combined Effect of Silica Fume, and Glass and Ceramic Waste on Properties of High Strength Mortar Reinforced with Hybrid Fibers

This study aims to investigate the effect of ternary combination of silica fume, and glass and ceramic waste as a partial replacement of cement on selected properties of mortar in the presence of steel-polypropylene hybrid fibers. Thirteen mixtures have been made: one control mix and twelve mixes in which the cement has been replaced by constant proportion (30% of cement weight) of ternary combination of silica fume, and glass and ceramic waste. The steel fibers have been added in the proportion of 1% while polypropylene fibers have been applied in the percentages of 0.25%, 0.5% and 1% (by volume for both fibers types). The flow rate, the compressive and the flexure strength and the bulk density tests have been examined. The hardened tests have been carried out at age of 28 days. Results have showed that the flow rate values have been reduced after replacing cement with the combination of silica fume, and glass and ceramic waste. Moreover, it has been found out that the compressive and flexure strength values for all combination mixtures have been higher than that for control mixture. The enhancement ranges have been 31% to 62% for compressive strength and 3% to 25% for flexure strength. In addition, results have demonstrated that there has been no significant change in bulk density values for cement replacement mixtures related to the one for control specimens.