A modified six sigma approach to improving the quality of hardwood flooring

Total quality or continuous improvement is a consensus theme used by many industries for improving product quality and service. In the last decade a newer quality philosophy known as Six Sigma has become well established in many companies, e.g., Motorola, General Electric, Ford, Honda, Sony, Hitachi, Texas Instruments, American Express, etc. Some have suggested that the Six Sigma quality improvement philosophy is not only impacting the global business sector, but will also re-shape the discipline of statistics. The Six Sigma philosophy for improving product and service quality is based upon existing principles established by other well-recognized quality experts, e.g., Deming, Juran, and Ishikawa. The significant departure of the Six Sigma philosophy from existing quality philosophies is that it promotes a stronger emphasis on monitoring production yield and manufacturing costs associated with any quality improvement effort. The other significant contribution that Six Sigma makes to the quality movement is the detailed structure for continuous improvement and the step-by-step statistical methodology. The goal of any Six Sigma improvement effort is to obtain a long-term defect rate of only 3.4 defective parts-per-million manufactured. The problem definition of the thesis was to determine if a modified Six Sigma philosophy for continuous improvement would improve the quality of hardwood flooring. The study was conducted over a six-month time period at a hardwood-flooring manufacturer located in Tennessee. There were six research objectives: 1) Define the current-state of product variability for hardwood flooring-veneer and the specific attributes of finished blank length, width, and veneer-slat thickness; 2) Determine the capability of the product attributes defined in objective one relative to specification limits; 3) Determine the current production yield and manufacturing costs associated with the manufacture of veneer-slats; 4) Define the sources of variability that influence the product attributes finished blank length, width, and thickness, and veneer-slat thickness (This involved a detailed understanding of the relationships that existed between key process variables that influenced finished blank length, width, and thickness and veneer-slat thickness); 5) Recommend to senior management the improvements necessary to enhance the overall quality of veneer-slats; 6) If any of the recommendations are adopted from objective five, the first four objectives would be repeated to determine if quality has improved. There were four major findings resulting from this work. First, there was statistical evidence (at α = 0.05) that top (p-value = 0.0007) and bottom (p-value = 0.0167) veneer-slat thickness increased as finished blank thickness increased. There was no significant statistical evidence (p-value = 0.3904) that indicated the thickness of the three middle veneer slats was affected by finished blank thickness. Second, 20% of rejected veneer-slats were good and 10% were down-gradable. Third, there was statistical evidence (p-value = 0.1126) that indicated rip-saw width was in control and the natural tolerance was 0.428 mm, which was within engineering tolerance. Target sizes of rip-saw width should be reduced to improve yield. Fourth, drying stresses and honeycomb were present in dried lumber. Drying schedules and proper conditioning of kiln loads were not appropriately executed. There was statistical evidence (p-value = 0.0001) that indicated top and bottom veneer-slat width was greater than the middle veneer-slats given the drying stresses. Four recommendations made to senior management were: 1) If finished blank thickness variation could be reduced by improving blank molder setup there would be a cost savings of $520,000 dollars per year; 2) A conservative estimate of the cost savings associated with the recovery of the 20$500,000 dollars per year; 3) Analysis of the rip-saw indicated an 8% yield increase if rip-saw target sizes and saw kerf were reduced and; 4) Appropriate drying and conditioning schedules should be followed to reduce veneer-slat width stresses and moisture content variation (eliminating top and bottom veneer-slat width variation would result in cost savings of $10,000 dollars per year). None of the previously mentioned recommendations would require capital investment by the company

Adjunctive interferon-γ immunotherapy for the treatment of HIV-associated cryptococcal meningitis: a randomized controlled trial.

BACKGROUND: Interferon-gamma (IFNγ) is of key importance in the immune response to Cryptococcus neoformans. Mortality related to cryptococcal meningitis remains high, and novel treatment strategies are needed. We performed a randomized controlled trial to determine whether addition of IFNγ to standard therapy increased the rate of clearance of cryptococcal infection in HIV-associated cryptococcal meningitis. METHODS: Patients were randomized to amphotericin B 1 mg/kg per day and 5FC 100 mg/kg per day for 2 weeks (standard therapy), standard therapy and IFNγ1b 100 μg days 1 and 3 (IFNγ two doses), or standard therapy and IFNγ1b 100 μg days 1, 3, 5, 8, 10 and 12 (IFNγ six doses). Primary outcome was rate of clearance of cryptococcus from the cerebrospinal fluid (CSF) (early fungicidal activity, EFA) calculated from serial quantitative cultures, previously shown to be independently associated with survival. RESULTS: Rate of fungal clearance was significantly faster in IFNγ containing groups than with standard treatment. Mean EFA [log colony forming unit (CFU)/ml per day] was -0.49 with standard treatment, -0.64 with IFNγ two doses, and -0.64 with IFNγ six doses. Difference in EFA was -0.15 [confidence interval (95% CI) -0.02 to -0.27, P=0.02] between standard treatment and IFNγ two doses, and -0.15 (95% CI -0.05 to -0.26, P=0.006) between standard treatment and IFNγ six doses. Mortality was 16% (14/88) at 2 weeks and 31% (27/87) at 10 weeks, with no significant difference between groups. All treatments were well tolerated. CONCLUSION: Addition of short-course IFNγ to standard treatment significantly increased the rate of clearance of cryptococcal infection from the CSF, and was not associated with any increase in adverse events. Two doses of IFNγ are as effective as six doses

Fundamental results from microgravity cell experiments with possible commericial applications

Some of the major milestones are presented for studies in cell biology that were conducted by the Soviet Union and the United States in the upper layers of the atmosphere and in outer space for more than thirty-five years. The goals have changed as new knowledge is acquired and the priorities for the use of microgravity have shifted toward basic research and commercial applications. Certain details concerning the impact of microgravity on cell systems is presented. However, it needs to be emphasized that in planning and conducting microgravity experiments, there are some important prerequisites not normally taken into account. Apart from the required background knowledge of previous microgravity and ground-based experiments, the investigator should have the understanding of the hardware as a physical unit, the complete knowledge of its operation, the range of its capabilities and the anticipation of problems that may occur. Moreover, if the production of commercial products in space is to be manifested, data obtained from previous microgravity experiments must be used to optimize the design of flight hardware

Ha-ras restriction fragment length polymorphisms in colorectal cancer.

The possibility of an association between restriction fragment length polymorphisms (RFLPs) at the Ha-ras gene locus and susceptibility to develop colorectal cancer has been investigated. Leucocyte DNA from 46 carcinoma patients and 49 controls was analysed by Southern blotting to determine the size distribution of restriction fragments containing the variable tandem repeat 3' to the Ha-ras gene. Four predominant allelic fragments were found in both groups (in AvaII digests having sizes of 1.55, 2.0, 2.65 and 3.15 kilobases [kb]), together with a variety of 'rare' alleles (with individual frequencies less than 5%). The overall prevalence of rare alleles was not significantly different between cancer and control groups. The distribution of the common alleles, however, differed significantly. The combined frequency of the two larger alleles (a3 and a4) was approximately twice as high in the cancer group (34%) as in controls (18%) (P less than 0.025), which was reflected in a highly significant increase in the proportion of individuals carrying an a3 or a4 allele

Prevalence of Inherited Hemoglobin Disorders and Relationships with Anemia and Micronutrient Status among Children in Yaoundé and Douala, Cameroon.

Information on the etiology of anemia is necessary to design effective anemia control programs. Our objective was to measure the prevalence of inherited hemoglobin disorders (IHD) in a representative sample of children in urban Cameroon, and examine the relationships between IHD and anemia. In a cluster survey of children 12-59 months of age (n = 291) in Yaoundé and Douala, we assessed hemoglobin (Hb), malaria infection, and plasma indicators of inflammation and micronutrient status. Hb S was detected by HPLC, and α⁺thalassemia (3.7 kb deletions) by PCR. Anemia (Hb < 110 g/L), inflammation, and malaria were present in 45%, 46%, and 8% of children. A total of 13.7% of children had HbAS, 1.6% had HbSS, and 30.6% and 3.1% had heterozygous and homozygous α⁺thalassemia. The prevalence of anemia was greater among HbAS compared to HbAA children (60.3 vs. 42.0%, p = 0.038), although mean Hb concentrations did not differ, p = 0.38). Hb and anemia prevalence did not differ among children with or without single gene deletion α⁺thalassemia. In multi-variable models, anemia was independently predicted by HbAS, HbSS, malaria, iron deficiency (ID; inflammation-adjusted ferritin <12 µg/L), higher C-reactive protein, lower plasma folate, and younger age. Elevated soluble transferrin receptor concentration (>8.3 mg/L) was associated with younger age, malaria, greater mean reticulocyte counts, inflammation, HbSS genotype, and ID. IHD are prevalent but contribute modestly to anemia among children in urban Cameroon

Neutron stars and strange stars in the chiral SU(3) quark mean field model

We investigate the equations of state for pure neutron matter and strange hadronic matter in $\beta$-equilibrium, including $\Lambda$, $\Sigma$ and $\Xi$ hyperons. The masses and radii of pure neutron stars and strange hadronic stars are obtained. For a pure neutron star, the maximum mass is about $1.8 M_{\mathrm{sun}}$, while for a strange hadronic star, the maximum mass is around $1.45 M_{\mathrm{sun}}$. The typical radii of pure neutron stars and strange hadronic stars are about 11.0-12.3 km and 10.7-11.7 km, respectively.Comment: 18 pages, 7 figure

Rotavirus genetic diversity, disease association, and temporal change in hospitalized rural Kenyan children

Background. The effectiveness of rotavirus vaccines will be dependent on the immunity conferred against prevalent and emergent variants causing severe diarrheal disease. Longitudinal surveillance of disease-causing strains is a prerequisite to intervention. Methods. Molecular characterization was conducted on rotavirus-positive stool samples from children admitted with diarrhea to a rural district hospital during 2002-2004. Extracted viral RNA was separated by polyacrylamide gel electrophoresis, and rotavirus VP4 (P types) and VP7 (G types) specificities were determined. Results. Among 558 investigated cases, the predominant genotype was P[8]G1 (42%), followed by P[8]G9 (15%), P[4]G8 (7%), P[6]G8 (6%), and P[8]G8 (4%), with 10% mixed strains. Overall, there were 6 different P types and 7 G types. No association was identified between genotype and child age, sex, or severity of diarrhea. The P and G genotypes and polyacrylamide gel electropherotypes showed significant temporal variation in frequency: P[8]G1 decreased from 51% (95% confidence interval [CI], 43%-58%) in 2002 to 30% (95% CI, 24%-37%) in 2004, and P[4]G8 increased from 2% (95% CI, 0%-5%) in 2002 to 13% (95% CI, 9%-19%). Quarterly data revealed seasonally endemic and emergence and/or decay patterns. Conclusions. Our study of rotavirus strains causing severe diarrhea in rural Kenyan children showed a predominance of P[8]G1 and confirms the importance of G8 and G9 strains in sub-Saharan Africa. Considerable genetic diversity of rotavirus strains was observed, including substantial mixed and unusual types, coupled with significant temporal strain variation and emergence. These results warn of variable vaccine efficacy and the need for long-term surveillance of circulating rotavirus genotypes